3. NBA Appraisal Certificates Issued to Sponsors of Low Rise Housing Systems in England and Wales

1.1 The Association’s first publication on this subject "Defects in Housing - Part I: Non-Traditional Dwellings of the 1940s and 1950s" was published in July 1983. That publication described the growth and subsequent decline of 'non-traditional' housebuilding and the enormous problem of defects now faced by local authorities. This publication traces the rise and fall of industrialised building in the 1960s and 1970s and finds a similar pattern of failure, on an equally large scale.

1.2 About 500,000 non-traditional dwellings were built but the programme had largely given way altogether to the traditional methods of the past by about 1955. Indeed, the immediate post war housing programme as a whole quickly declined and priorities changed. There was no longer the imperative to expand beyond the constraints of the traditional building industry. Indeed local authority completions rapidly fell to one-half of the peak 1953 level by 1960. But the decline in housing activity between 1955 and 1963 meant that once again a backlog of housing needs was accumulating and a new ‘non-traditional’ building phase was already being perceived as the inevitable answer.

1.3 A new period of high activity began in the mid-Sixties and this included the production of up to 1 million industrialised and system built dwellings. There were many similarities to the non-traditional’ programme - Government sponsorship and encouragement, a favourable subsidy system, technical advice and guidance and collaboration with the construction industry by central Government and its agencies. There were also some notable differences - in the 1960s the shortage of land, the demands of the building industry, and the apparent design freedom led to new forms of development which not only had an impact upon city skylines, but also the new development forms had a profound effect upon community life. Many social considerations have therefore compounded the problems of physical defects.

1.4 This assessment of past experience is relevant today - with such low levels of new housebuilding currently in the public sector and the mounting disrepair and unfitness in the existing stock, both public and private - we feel that it is inevitable that a sudden growth in housing expenditure will be inescapable in a few years’ time. It is to be hoped that in order to cope with any new boom we do not again attempt to supplement tried and tested design and techniques with new methods. Nevertheless, the temptation will be there - the traditional building industry will not have the capacity and skilled labour and traditional materials will not be available in the capacity required. We must learn the lesson of the past - sudden expansion of the building programme to meet political objectives and deal with new housing crises - have provided short term ‘solutions with devastating effects in the longer term. Slump and boom in housing programmes must be avoided and higher levels of investment are now necessary with a long-term (say 10 years) strategy which allows for the gradual expansion of the construction industry.

1.5 We are naturally most concerned now with our financial position and, since the publication of our first report, the Government have recognised that substantial problems exist with the ‘non-traditional’ dwelling stock and have made provision for the private owners of these dwellings. Thus, the central role played by Government in the development of these dwellings has been acknowledged. The development of industrialised dwellings also depended upon Government, and we believe that for both these and the earlier types there is a strong case for some measure of compensation to be made available to the local authority owners concerned. The present discrimination cannot be justified.

1.6 Unfortunately, the problems of both 'non-traditional' and system built dwellings are emerging now, at the very time when housing investment is being substantially reduced. The Government also proposes that Housing Investment Programmes (HIPs) are further reduced, in real terms, in 1984/85 and 1985/86 (72). Capital receipts, from council house sales and sales of other assets, have not restored the level of housing investment. In fact, as capital receipts have risen HIP allocations have fallen with ‘gross provision’ declining in real terms very substantially. Local authorities are having great difficulty in funding the cost of remedial works programmes within their HIP provision. Inevitably the demands of existing tenants in existing housing will take priority in most programmes and therefore the proportion of HIP expenditure spent on renovation of the public stock has increased - but at the expense of other programmes, notably new housebuilding.

1.7 Revenue costs are also significant. There are both the effects of maintaining a loan debt for the remaining 40 or 50 years on dwellings demolished, and the annual repayments and interest on new loans for remedial works. In addition, the physical defects and social problems often have to be tackled together and this leads to extra manpower and other revenue charges.

1.8 In our earlier publication (30) we referred to the difficulty in collating details of the types of 'non-traditional’ dwellings, and qualifying their associated defects. Whilst the 1960s and 1970s dwellings are 20 years younger the same difficulties apply. There are few publications which attempt to identify the types, and official statistics are limited. There has been virtually no attempt to record the associated defects in any systematic way and we have therefore had to rely upon research from member authorities and limited published material.

1.9 Our information cannot ever be fully comprehensive, but does represent the experience of metropolitan districts at least. Even so, difficulties in identification of the many systems and the recording of defects associated with each type means that it is no easy task for authorities to be entirely clear about the exact nature of their own problems. We would hope, however, that the information presented here is taken as a broad expression of the size and nature of the problem and is probably the best estimate yet available. We must, however, reiterate our view from our previous work that a fuller investigation is needed, and that this can only be undertaken by central Government.

1.10 The concept of traditional building changes over time. In the strictest sense it implies the use of certain materials, such as bricks and blocks, which are established in the building industry; and an organisation of the building works itself with the components or materials being brought to the site and erected in a recognised order.

1.11 Traditional building has, however, become increasingly industrialised. Firstly, prefabricated components such as roof trusses, lintels, and staircases are now common place, and secondly the building process has become far more mechanised. The industrialisation of the building process aims to reproduce the conditions of the factory, by prefabricating components off site in the factory, (or by on 'on-site' factory production), with a mechanised system of assembly. An 'industrial method' would therefore include in-situ casting.

1.12 Traditional building can therefore be industrialised to virtually any degree. The point at which a building becomes 'industrialised' is not clear cut. However, it is usually taken to mean the point at which most of the main structural elements are prefabricated (or cast in situ) and assembled on site as an unskilled or semi-skilled operation employing a high degree of mechanisation.

1.13 Non-traditional building is a narrower concept than industrialised building', and implies the use of unfamiliar building materials (notably for the external walls) which were often prefabricated, or cast in-situ. Whilst some increased mechanisation was often associated with the construction of non-traditional dwellings, it did not attempt (unlike industrialisation) to rationalise the whole design and construction process.

1.14 System building is what we are most concerned with here. In the 1960s and 1970s there was a tremendous growth in industrial methods generally, but the 'system' took this a stage further by producing a combination of materials and methods for a design and construction package. Heavy reliance was usually placed on industrialised methods. The system may have been derived from earlier design concepts or built around one component that a firm had on offer and wished to promote an entire system which took advantage of that product. Systems were either proprietary or non-proprietary, although the majority were associated with one particular builder or developer.

2.1 As with the 1940s and 1950s non-traditional expansion, and indeed that of the 1920s, it was the backlog of housing problems which were again growing to crisis proportions which led to a rapid expansion of the housing programme and necessitated the use of new methods in housebuilding.

2.2 The immediate post-war period concentrated upon the production of new homes and the repair of war-damaged and other houses in disrepair. By 1954 the Government had achieved a new record level of completions of over 300,000 homes and the worst effects of shortages were beginning to come to an end. But this programme growth was not sustained (see Table I), and public sector activity rapidly declined. Housing need did not, however, decline and difficulties with the deteriorating older housing stock, in particular, became increasingly more evident.

2.3 In 1953 the Government attempted to estimate (1) the number of unfit dwellings. 140,000 slums remained to be dealt with from pre-war programmes. More dwellings had deteriorated since the war and whilst "assessments vary.... the number certainly runs into hundreds of thousands." The problem was indeed large - "of the 7¼ million houses owned by private landlords over 2¼ million are 100 years old or more; a further 1¾ million are more than 75 years old; a further ¾ million are over 65 years old"(1)

There were also some problems of unfitness in the 3¾ million owner occupied dwellings and the 2½ million rented in the public sector.

2.4 Unfortunately the Government's white Paper 'Houses the Next Step' (1) recognised the problem of older housing that lay ahead, but paid scant regard to the need to continue with a high level of public sector housing output, and as our earlier work has shown (30) and Table I illustrates the housing programme was allowed to decline.

2.5 Turning its attention to the older housing stock the Government introduced the Housing Repairs and Rents Act in 1954. This amended the law relating to clearance and compulsory purchase and local authorities were required to estimate the number of slums within their area against a new standard of fitness which was laid down for the first time. New impetus was also given to house improvement. The local authority estimate of the total unfitness problem was a staggering 847,000 dwellings (32). This compared with a clearance programme of about 30,000 a year, and whilst rising (see Table 2) was clearly unlikely to have much of an impact on the problem.

HIGH RISE BUILDING, PUBLIC SECTOR, 1953 TO 1963, ENGLAND AND WALES

No. built by Bison Concrete 50,000 (UK)

(Note: This latter figure has been confirmed by Bison Concrete Ltd, and includes 20,000 low rise dwellings which were not listed in Government Statistics at all.)

Further, a comparison of official statistics from other publications (65), (67) shows that a considerable number of systems which were used in this country were not included in Government statistics, and some that had been built in much greater numbers than officially recorded.

3.7 Appraisal certificates under Circular 76/65 (17) were issued for 89 low-rise systems (37). These are set out in Appendix 3. These were issued as follows:

However, of the 89 issued, 29 did not figure in later Housing Statistics for industrialised building activity. This may be due partly to the inadequacy of the statistics, but also to a decision by the sponsor not to go beyond the design and prototype stage.

3.8 Whilst in terms of absolute numbers there is some considerable reason to doubt the accuracy of official 'industrialised building' statistics, the distribution over the years shown in Table 5 is probably fairly accurate, apart from the first two years of statistics collection when under-reporting was likely to occur. The industrialised building activity did indeed reach its peak in 1970 and overshot the target of 40% (see para 2.53). However, with Ronan Point and the growing expression of doubts there was an immediate decline, with a gradual falling from favour thereafter. Many of the contracts let in the late 1960's would have taken 3 years to come to fruition and explain why industrialised building continued at a high level (i.e. a quarter) until 1974. The final demise came when volume building plunged in the late 1970's.

3.9 In Section 2 the origins of the growth in industrialised building has been analysed. High rise building was established first:

"developments such as Harlow, where the first tall point block was used in a scheme of 1950. Probably the most influential and widely acclaimed mixed development scheme of this period was the LCC's Alton Estate at Roehampton (begun 1951) where a balanced group of eleven-storey point blocks and other types were built" (32).

Not all high rise, however, was industrialised but, as Table 6 demonstrates, the foothold of high rise was being established in the early 1950's. ' The nature of high developments, with repeated floor plans, lent itself to industrialisation - as did the building operation itself. Also, the Continental experience, which had concerned itself less with non-traditional and low rise development, was available for transfer to Britain during the later 1950's.

3.10 In May 1965, Mr P Lederer, the newly appointed adviser to the Minister on industrialised methods (16), produced his first report (18). By this time Mr Lederer felt that high rise industrialised methods were 'already more economic than traditional methods' and were 'proved systems'. For medium rise, and low rise, it was quite another matter however, and Table 7 illustrates the limited success of industrialised methods for the different forms of development.

3.11 Mr Lederer's report (18), in essence, said that local authorities needed little convincing about the value of industrialised methods for high rise dwellings. However, he felt there was resistance to industrialisation of low and medium rise dwellings because of maintenance and durability considerations. Whilst the NBA's role was:

"To confirm that systems subjected to their examination have a 60 year life, subject to reasonable maintenance work being carried out. I have found that some councillors and officials view such opinions with reserve based on unhappy technical advice given by Government agencies in the past."

Mr Lederer recommended the 'appraisal certificate' system, and this was one of the major means of creating confidence in low and medium rise industrialised methods. (See paras 2.58 and 3.13 and Appendices 1 and 3 for further details.)

3.12 It is interesting to note here that high rise systems were subjected to examination by the NBA (8) though no appraisal certificate was issued (see also para 2.50). The Minister subsequently announced that they would be given for high rise systems (17), but this subsequently proved not to be the case (37). The drive towards industrialising low and medium rise was successful as Table 5 demonstrates by increase in the proportion of industrialised dwellings above the proportion that were in high rise form. Indeed, it had to be successful if industrialised building targets were to be met, given that the proportion of high rise flats had gone about as high as it would ever go. (It, in fact, reached a peak in 1966 when 25.7% of all dwellings in the public sector were 5 storey and above.)

3.13 The basis on which appraisal certificates were issued was set out in an appendix to Circular 76/65 (17). This appendix is included in Appendix 1 to this report. Appendix 3 lists the appraisal certificates given for 89 low rise systems up to 1969. A typical appraisal certificate gave the following information:

In addition, an assessment was made of the following features on the system with the options deleted as appropriate:

Clearly, local authorities will have been very much influenced by these assessments. However, as pointed out in Section 2, the direct role of central government agencies in organising housebuilding programmes at this time was also very strong, as informal comment and the constraints of what was available may have been the overriding factors. Local authorities are now, no doubt, considering the assessments made by the NBA in the light of actual experience with these systems.

3.14 Local authorities were encouraged to form consortia to further standardisation of design and production. Systems could be developed exclusively where the number of authorities could pool their work to ensure sufficient demand collectively. In local authority housing, probably the Yorkshire Development Group and the Midlands Group were the best known. Consortia also existed for schools, where some 15% of school buildings used "advanced systems of construction" by 1963 (28). These included CLASP (Consortium of Local Authority Schools Programmes) and SCOLA (Second Consortium of Local Authorities).

3.15 The gas explosion in Ronan Point in May 1968 marked the turning point in the fortunes of industrialised housebuilding. High rise building, however and some medium rise had already declined to some extent (see Table 5) and had by then already been criticised, and as the initial 'shine' wore off, the tenant reaction grew stronger. The success of the low rise industrialised programme, which was proving cheaper for the Government (after taking account of subsidies) and the price per unit was reducing.

3.17 Housing Standards, Costs and Subsidies MHLG Circular 36/67 (17) announced the introduction of new cost yardsticks for housing schemes. Schemes would not receive loan sanction if their costs exceeded the yardstick by more than a tolerance of 10%. The yardstick level was set so that local authorities would be able to achieve Parker Morris standards without exceeding them. The Circular said: "The Minister therefore considers that housing authorities should only build to these (very high) densities in exceptional circumstances" and then only "in the most congested urban areas where existing densities are even higher and where there is an acute shortage of building land e.g. only in the central parts of conurbations and particularly in inner London". The Circular went on to explain "how wasteful it can be in money terms to build to densities higher than are really necessary". It also states that at high densities, dwellings in high blocks cost some 25% more than those in blocks of 3 to 4 storeys, or 50% more than equivalent houses. It refers to Planning Bulletin No 2 "Residential Areas Higher Densities" (18), first published in 1962 (see para 2.16) which shows that land savings diminish at higher densities, once density is increased beyond about 20 dwellings per acre development above 2 storeys becomes increasingly necessary and building costs begin to rise sharply.

3.18 The Housing Act 1967 abolished the special extra subsidy for flats for each storey above 6 storeys. Subsidies for dwellings in flats over 4 storeys were set out as follows (Section 4): (c.f. 1965 white Paper (15) - see para 2.55).

Arrangements for expensive sites were, however, retained and this helped the transfer from high rise to low rise systems that utilised fairly high density layouts.

3.19 The cost of industrialised methods was probably never much below that for traditional building, and mostly it was higher. In 1965, for example, Mr Lederer reported (18) that the cost of the average high rise industrialised dwelling was £3,047 compared with the traditional cost of £3,152, but other types were less competitive. Costs for industrialised methods were generally acknowledged to be higher except in the most favourable circumstances of volume and standardisation (see, for example, para 2.53).

3.21 This section is based largely on a paper by A W Cleeve Barr to the AMC Conference in September 1963 (29). The systems referred to are not necessarily defective - some have performed well as far as we are aware, although equally, some have proved exceptionally problematic.

These systems were developed first in France, Scandinavia and the USSR for multi-storey housing. They consist largely of pre-cast concrete walls, floors, and other elements, made in large panels in specialist factories, delivered to building sites by special transporters and lifted into position by cranes. They were mainly systems of rationalising the erection of the structure of multi-storey buildings. Some firms went a good deal further than others in incorporating service pipes, electric’s, and fixings for equipment, in the concrete panels. The units weigh from, say, two to five tons for transport to a radius of 40 or 50 miles from the factory. Some systems used a factory on the building site, for which a large contract was obviously required, and cast units up to ten or twelve tons in weight. Such a unit would be the entire party wall between two flats, one storey height and the full depth of the block from back to front -alternatively, the floor of a flat from wall to wall, and back to front of the block.

In these systems windows and doors are cast in the wall panels in the factory, and may be glazed and painted in the factory as well. The floor finishes and the heating may also be cast in. Plastering was eliminated, and walls, which were brought to a degree of accuracy in the factory, that permitted finishing on the site with wallpaper or plastic paint on to the concrete.

By the use of these systems construction times for multi-storey flats were said to be reduced to under six months for blocks which formerly would have taken two years or more. Productivity in terms of man hours was increased by 40 per cent. Many British contractors took out licences to develop systems on these lines in this country, either by extending existing factories or laying down new ones. They included: -

Wates (A firm which had a factory-based system for houses and flats early after the War, and which now has a new technique of on-site pre-casting).

Lightweight concrete is produced either by using a lightweight aggregate (e.g. clay expanded under great heat) in lieu of gravel, or by generating a gas through a mixture of cement and sand, so that the resulting material consists largely of tiny disconnected hollow bubbles bound together by cement. According to the purpose intended the material can be made very light, a fraction of the weight of ordinary concrete, in which case it has little structural strength but high insulation value, or it can be made, say, one-third or to one-half the weight of ordinary concrete in which case it has both useful strength and useful insulation values. A number of firms produced it in ordinary block sizes, say, 20 in. long by 8 in. panels for storey-height walls or large roof spans requires elaborate steam-curing kilns. Storey-height panels were produced in Britain by Durox Limited, by Costain’s and by John Laing -who also acquired patent rights for Scandinavian systems respectively known as Ytong and Siporex (based on materials of the same name).

The material was adequate for the structural walls of two-storey houses, but only for the non-structural walls of blocks of flats. A storey-height panel could be lifted by two men. It took nails or screws direct for fixings. It could be cut with a saw. It could be wallpapered or painted direct. Sound insulation values for party walls was said to be initially a problem, and insulation values were described as good.

This type involved a high degree of site mechanisation, combined with the factory production, not of finished building products, but of the formwork within which the concrete was poured on site. In brief, these systems made maximum use of concrete for all the possible building elements - walls, floors, partitions, roofs - for which concrete in various firms was suitable. The concrete was centrally mixed on site, and either pumped through hoses or lifted by crane to where it is needed. The formwork was made of steel or timber, its facing depending on the degree of precision wanted in the finished face of the work.

The SSHA were amongst the earliest developers of this system and were responsible for much of the early development work.

Firms who used this kind of system included the following. A few notes are necessary because of the variety of techniques within this general classification:-

A system using "no-fines" concrete, that is, concrete with no sand. A "no-fines" concrete does not flow, like water, and therefore builds up less pressure in the formwork, and could be cast more economically. It also contains air gaps and has a small insulating value. The firm developed a dry-lining instead of plaster.

A similar system, developed jointly with the LCC, using an Austrian method of making the formwork. It used a different aggregate in the concrete to improve the insulation values.

A rapid system for tall blocks using dense structural concrete, with highly standardised factory-made formwork, incorporating heating pipes for quick curing of the concrete on site.

A system for the structure of tall blocks using dense concrete, poured into formwork, which incorporated hydraulic jacks, and which rose continuously as the concrete was poured.

A system for two-storey houses using lightweight insulating concrete, which could be wallpapered direct. Traditional external finishes.

A completely flexible system permitting any detailed planning arrangements to the client's requirements developed by the Ministry's Development Group in collaboration with the Yorkshire Group of authorities. Light steel columns, but all other components timber-framed. Various external walling materials (5M = 5 modules, or five times 4 in., the basic module of the system). This system had an interesting factory-made party wall, consisting of two leaves of thick laminations of plasterboard with a cavity and a lead sheet in between them. (See references 14 and 21 for further details.)

A technically advanced system using a light pre-stressed pre-cast concrete post and beam frame with timber infill panels. External claddings of concrete tiles and timber boarding.

A system, developed initially in association with a City Architect's Department, as clients. It consisted basically of a rigid-jointed light steel frame, with pre-cut timber floors and roof, leaving the party walls, cladding and so on, to be carried out in traditional or pre-fabricated components. This was developed later from a timber core and metal web 'beam' unit into all steel units.

Standard steel sections assembled to form a frame infilled with timber and faced with a variety of claddings.

A pressed steel frame at close centres, used for low and medium rise construction.

A system developed by Messrs Hallam in collaboration with a local authority City Architect. It used factory-made two-storey height timber wall units, floor and roof units, with brick party walls and certain external facing walls in brick. Finishes were described as excellent by Cleeve Barr (28).

A system developed by Messrs Spooner in collaboration with a local authority City Architect. Large factory-made timber components. Some external facings in brick. Party walls in poured concrete.

A timber framed system developed in collaboration with a Midlands Borough Architect. It has two-storey height factory-made wall units with party walls in blocks.

A system devised by the Timber Research and Development Association. It used load-bearing timber panel walls, with intermediate post and beam frames, where needed in wider spans. Timber external walls, with concrete party walls similar to Spooner.

4.1 The following defects have been identified by member authorities in their industrialised housing stock, and also drawn from published material. It must be emphasised that not all the defects referred to are a function of industrialised building. They are defects commonly found in dwellings of this age and type. Nevertheless, in general, the defects referred to are more prevalent in industrialised building than in traditional forms, and may sometimes be attributable to the built form - which was determined by the possibilities created (and limits imposed) by the industrialisation process. Furthermore, industrialised building relied heavily upon the use of certain materials and components, such as asbestos - necessary in the lightweight structures (largely a function of prefabrication, transportation and crane handling) for insulation and fire protection.

4.2 Many of the defects cited by members were related to particular systems, but in view of the consistency of complaints across systems, and relevant to types of construction, and particularly high rise dwellings, the defects have been grouped under the following headings:

4.3 Reference has also been made to the problems of built form associated with industrialised types, and high rise in particular. It has not been our intention to catalogue these problems in a comprehensive and systematic way and the main focus of our work has been on defects problems. Nevertheless, the two problems cannot be viewed separately and we have therefore attempted to explain the relationship between the two.

4.4 We must reiterate the view expressed in our First Report (30) that a more thoroughgoing and comprehensive study of this problem is now necessary. Once again, we have been struck by the difficulty in identifying the systems used, and the adequacy of records and statistics which would have helped us to quantify the scale of the problem involved. We have also been struck by the lack of central advice and guidance to identify defects and devise schemes of remedial works. Local authorities are having to solve problems virtually unaided.

4.5 No mention has been made of the specific problem highlighted by the collapse of Ronan Point in 1968 which, it is assumed, has long since been completed. It was found (25) that blocks of this type could be liable to progressive collapse in the event of an explosion, or fire, or other forms of accidental damage, including wind damage.

Appraisal was required of all blocks over 6 storeys "in height built of large pre-cast concrete panels to form load bearing walls or floors, or both" (26). Existing buildings were subsequently strengthened by making joints more continuous and tougher, and so disposing the load bearing walls that alternative paths are provided in the event of local failure. The new standards also applied to new buildings of this type. Grants were paid for this work, and this extended to tenants' expenses and loss of rental income (27). Geoff Scott (46) estimated the total cost of this work at £l00m.

A number of defects seem common to high rise (and indeed to some medium rise) Systems, but built by a variety of industrialised methods. Whilst the 'system' designs have suffered heavily from defects, they were built in greater numbers than 'individual' or 'local' designs. However, the 'one-off' industrialised dwelling may not have fared any better, and they are well represented in the listed defects.

Rain penetration has been a major problem. This has occurred through parapet walls, through brickwork panels, around and through other claddings, and particularly through panel joints, and at the junction of the frame with cladding. It is also prevalent around window frames, and has occurred in unusual spots such as through lift motor rooms.

Naturally, rain penetration has contributed to the discomfort of tenants, but has also contributed fundamentally to the deterioration of the structure of the building itself.

The exposure conditions in the upper floors of high rise dwellings was not generally appreciated and accounted for in the design. This is clear from the Ronan Point investigations (25) which emphasised the stress created by strong winds at those heights. Similarly, standards of water-tightness applied previously to low rise dwellings were not adequate for multi-storey blocks. Any hairline crack could permit rain into the cavity and wind pressure was such that it could be blown across to the inner leaf, or driven into unprotected areas of window frames, behind claddings, decorative facings and so on. Cavity trays which were slightly defective (and would give rise to no problems in a low rise application) would not perform their task adequately.

The cracking of decorative panels, delamination of finishes, rotting window frames have all become major problems.

The problem of watertightness has been made worse by the use of different materials together, for which no adequate allowance has been made for differential movement. A serious example, of which many authorities have complained, is the differential movement between a concrete frame and brickwork infill panels, and other cladding materials. In the case of brickwork, cracking of the bricks or concrete frame, or both, has resulted with spalling and possible structural failure.

Differential movement has also occurred on parapet walls, and between cladding panels and window frames. Another example is between in-situ concrete and pre-cast units which have a different composition. A significant problem has also been the dislodging and cracking of cavity trays.

Condensation has been a major difficulty too, with the structure being exposed to very much colder conditions at higher levels. Coupled with rain penetration problems, and cold bridging at floor and ceiling junctions of external walls, condensation has proved difficult for tenants to control. Authorities have attempted to improve insulation by dry lining techniques, externally applied insulation, and by cavity filling. However, these are expensive and usually imply some additional structural work and not generally simple to introduce.

Condensation has also been reported as a cause of electrical failure, and deterioration of insulation boards and surface finishes.

Roofs - flat and low pitched roofs are more often to be found in industrialised and system built dwellings. This is because they could more easily be prefabricated, and because weight could be kept to a minimum. (Reducing the weight of the structure, largely for handling, was a major objective of the industrialised building programme - see Cleeve Barr, Chief Architect MHLG (28)).

Flat and low pitched roofs have (typically) performed badly. Water penetration is a common complaint, and poor insulation values added to condensation problems. Performance has, however, been worse than for traditional construction due to the high exposure conditions, and their inability to cope with differential movement, settlement, and thermal expansion and contraction.

Replacement with conventional roofs has in some cases been prevented by the difficulty that the existing structure would have in coping with the extra weight imposed.

Sound insulation has been a noticeable problem, though perhaps particular to some dwellings. It has been a special problem where deck access ways have been positioned above dwellings.

Noise has been transmitted through gaps between dwellings and there have been several examples of the isolation of dwelling units being far from complete. This, of course, gives rise to other problems, such as smell and smoke (in the case of fire) transference and a through route for vermin.

Spalling concrete has been evident from a wide range of systems, and generally caused by the presence of chlorides or the lack of cover to steel reinforcement. Again, the process of deterioration is accelerated in higher exposure conditions.

Concrete which is exposed, (floor slabs, parapets. balconies etc) has been most affected. The lack of cover to reinforcing and the porosity of the concrete has provided inadequate protection for the reinforcement. A separate, but related problem has been the use of calcium chloride which was widely used to accelerate concrete setting times up to the mid 1970s. Deterioration is precipitated by the weather. Both problems result in thereduction of alkalinity of the concrete and weaken weather resistance. However spalling concrete due to lack of cover to reinforcement and concrete porosity may be localised (although often widespread in any structure) whereas the use of calcium chloride produces a chemical change throughout the exposed concrete areas. This is difficult, if not impossible, to arrest.

Localised damage is itself expensive and difficult to treat; calcium chloride problems threaten the whole structure, and a far more difficult and complex. It is also clear that some of the problems are yet to manifest themselves due to the comparatively recent completion of buildings using these materials.

Calcium chloride was also used on a pre-cast units, particularly panels, and ‘patch’ repairs might be undertaken initially but are unlikely to be appropriate in the longer term.

Asbestos products are not confined to industrialised building systems. Nevertheless they are for more prevalent. This is largely due to the use of prefabricated components and the emphasis placed on light weight structures. Asbestos was used to give fire protection to structural components such as metal beams, and to prevent fire spread from heating ducts and flues. It was also used in claddings, and with other materials in external and internal panels.

The Association has found that most of the problems of asbestos in housing which members now face are indeed concentrated on the post-war non-traditional and industrialised stock.

High alumina cement has featured in public campaigns in the past, and many difficulties have been dealt with. However, deterioration is progressive, and it is not always easy to identify. It is therefore anticipated that this will continue to manifest itself as a problem in various situations.

External staircases, walls, and link bridges have also suffered from a combination of thermal and differential movement and weather damage, including spalling of concrete. Asphalt coverings have also had to be replaced to walkways as a result.

One frequent complaint has been deterioration to balconies, and particularly balustrades guard rails, and asphalt surfaces. Again, it seems that the weather and higher exposure conditions have caused rapid deterioration, together with poor workmanship and inadequate detailing.

Drainage problems have also occurred and proved particularly difficult to remedy. Drainage runs may have been cast within the structure, and the source of leaks difficult to establish, and rodding eyes inaccessible or not provided.

Insufficient ties between inner and outer leaves of external walls (panels), resulting in movement and, in some cases, falling out of panels.

Bowing of pre-cast concrete panels causing cracks between floors and the external wall - permitting noise, smell, and smoke (in the case of fire) transferred between flats.

Inadequate fixing of stud partitions and exacerbated by doors fixed to partitions which are too flimsy - or where it is difficult to obtain adequate fixing.

Inadequate mechanical connection between load bearing wall and floor panels, and lack of restraints between buttress walls (and spandrel panels) and load bearing walls.

Pre-cast panels spalling or chipping with corners proving particularly vulnerable. Largely due to presence of chloride or inadequate cover to reinforcement.

Condensation: A widespread and general problem associated with poured concrete and no-fines construction. Particularly exacerbated by cracking and spalling of render cover, and rain cooling the structure from the external face.

Spalling of Concrete: Again, fairly widespread, from exposed areas, associated with the corrosion of reinforcement due to the presence of chlorides or inadequate cover.

Numerous problems have arisen, but these are difficult to categorise because of the variations and unusual nature of the systems.

Rain penetration has been a problem between the junction of the house frame and various claddings, and particularly around doors and windows. Door and window frames have had to be renewed after only 10 years.

Claddings have also provided problematic and not only failed to keep out the elements but have deteriorated due to lack of watertightness. This has resulted in bowing and corrosion of cladding and delamination of the external finishes.

Roofs have been a special problem, with several authorities replacing corrugated metal sheet roofings. Low pitched roofs have been especially difficult and condensation in the roof space hard to avoid. The fixing of roofs to house frames has also been inadequate in some cases, with one authority reporting 16 house roofs blowing completely off in one night of gales. To re-roof in a traditional form, however, adds considerable weight, and the existing structure may not be capable of supporting this.

Differential movement has also proved a major problem with the house frame, cladding, and components expanding and contracting at different rates. In some cases, this has caused severe structural problems.

With the emphasis on lightweight materials, the rigidity and robustness of the structure has been in doubt with, for example, flexing of entire pre-fabricated floor units, and constant movement cracking surface finishes.

The linking of traditional heating appliances to prefabricated flues has also created problems, and the flues in particular proving to be insufficiently durable and inadequately protected against the possibility of fire spread.

Asbestos has also been used in some of the systems using composite pre-fabricated panels for external walls, and also to line flues, in lieu of brickwork, and for heating ducts, etc.

Upgrading thermal insulation has also proved difficult, and in some cases impossible in roof spaces with limited space.

Fire barriers in the cavity of external walls have been omitted. This has permitted fire spread in houses via the cavity, and also between dwellings where cavity barriers have also been found to be inadequate or omitted altogether.

Roofs have proved to be a particular problem, with extensive roof leaks, especially to flat roofs, being reported, condensation in the roof space, and roof coverings being susceptible to differential and thermal movement. In one case, there has also been differential movement between the roof and rainwater stacks, allowing rain to stand in pools.

Differential movement between the cladding and the frame has led to cracking of the structure, gaps around window and door frames, and cracking and rotting of those frames resulting. Rotting structural timbers have also been evident. Some problems have been found where the timber frame (and windows) have shrunk downwards causing the external timber cills to force down the back of tiled cills so that joints are broken and back fall created allowing water penetration.

In the external walls, insulation has been found to be missing or insufficient, and vapour barriers have not been continuous in some cases. Cold bridging at ground floor panel level has also been found.

Asbestos has also been used in the external walls of some systems, and also for ducting and protection to heating appliances.

4.11 Industrialised building dictated the built form and estate layout. Initially, at least, industrialised building was only available in high rise forms and in 1964 twice as many units were still built in high rise forms compared with low rise (see Table 7). Industrialised building found it difficult to compete with traditional forms in low rise development whereas high rise and, to a large extent, medium rise could rely on repetition of standard units vertically and with higher densities were able to bring down unit costs.

4.12 Repetition of standard units imposed considerable constraints upon the built form - point blocks, large slab blocks, deck access terraces, etc. However, their position on site and proximity to each other could also be determined by other physical factors such as crainage. Barry Russell (63), for example, shows how for one LCC development blocks were located in such a way so that they could be served by one crane.

"The community is socially more closely integrated the decks are protected from the weather and provide a convenient route for household deliveries, and are a natural meeting place for young and old alike.".

4.14 Little was known, however, about how the occupiers would react to their new environments and there was little design knowledge which would ensure that the schemes actually worked in practice. The fundamental problems, especially for families, of having play space and drying areas many floors below were foreseen to some extent and views varied as to whether families should be housed only on lower floors etc. However, more detailed points, and especially, coming to terms with the concept of 'defensible space' were not well understood. Vandalism, insecurity, cyclists on walkways - and a host of problems not experienced in traditional layouts were simply not catered for.

4.15 It is not our intention to discuss in detail all the problems which have arisen from the layout and built form of industrialised building. Much good work has already been done on this aspect elsewhere and we would draw attention to the Government's own work on 'Priority Estates' and similar projects (53), (54), (55), (56), (57), (58), (60), and the recent publication by the Institute of Housing "Trends in High Places" (52). New entryphone systems, floodlighting, redesigned communal areas, extra security staff/caretakers/resident managers, blocking off secondary accessways and perimeter fences are now fairly commonplace in an attempt to deal with the unforeseen problems that arose from the new layout arrangement and built forms.

4.16 Certainly, the Department of the Environment now recognise these problems and there is an appreciation of the relationship between physical defects and built form:-

"Many authorities began their programmes short of land and assuming a continued growth in population. Hence, metropolitan authorities particularly resorted to high density, multi-storey schemes on both redeveloped and peripheral overspill sites. An adjunct to this approach was the use of industrialised building systems. Although central government never set out a clear policy advocating high rise or development at high densities, its subsidies at least facilitated these practices; it also promoted industrialised building systems as a means to speed housing production and overcome labour shortages.

The results in some instances have all too clearly been developments which are inhuman in scale, uniform and repetitive in appearance and inadequately provided with social and community facilities. An industrialised building system had been employed on 16 of the sample estates and many of these had massive concrete facades of overwhelming severity which sophisticated and generous landscaping (if provided in the first place and if it survived) could do little to mitigate.

In addition to their often unattractive appearance, technical problems such as water penetration were not uncommon with the system built schemes we looked at.

Some of the systems had evidently been adopted before being sufficiently tried and tested, or else they had been crudely adapted to specific site conditions or density requirements.". (53)

Now, with the benefit of hindsight, the Government is prepared to recognise at least some of our difficulties and the above quotation by the Department of the Environment represents a complete change of direction to that advocated by their predecessors only 15 years ago.

5.1 The Association is disappointed with the recognition that Government has been prepared to give to the problem of defective dwellings generally. The cost of remedying defects is escalating all the time as faults are becoming manifest, and local authorities are having to devise programmes to safeguard the structure, protect the tenant, or both. However, Housing Investment Programme allocations have been reduced in real terms by around 50% since 1979. An increasing proportion of HIP allocations is also being found by the local authorities themselves by way of capital receipts. In addition, pressure to tackle the increasing unfitness and disrepair in the private sector has meant a much greater proportion of HIP allocations have had to be devoted to this activity. New housebuilding has suffered most, but even the dramatic reductions here have not allowed local authorities' expenditure on repair and renovation of their own stock to keep pace with, and certainly not rise to, the level required.

5.2 In the current round of HIP negotiations for 1984/85, the Department of the Environment did show some willingness to redistribute resources between authorities and to direct them to those authorities with the greatest defects problems. Consequently, regional officers' discretion was increased from 40% to 50% outside London, but our preliminary analysis of HIP allocations indicate that authorities with known large defects problems actually received a decrease in allocations. This may also be affected by other factors, but it is clear that whatever the final explanation, the measures have had no meaningful effect, and are quite inadequate, and will have no impact on the problem at all. The Department of the Environment have shown a willingness to find an indicator within the General Needs Index which can take account of defects in a mechanical way. The Association remains sceptical about this proposal, and continues to argue for more resources, outside the existing framework and to fully reflect the magnitude of the problem.

5.3 The Government firstly accepted that some provision should be made for Airey dwellings, and repair grants were made available to private owners (50). The vast majority of these dwellings remain in public ownership, and no additional finance has been forthcoming for remedial works, nor seemingly, to reflect the additional capital to meet the repair grants given to private owners.

5.4 The scale of the problem has begun to dawn gradually upon the Government and the Association has recently been consulted on some new proposals to assist private owners of other types of prefabricated reinforced concrete (PRC) dwellings. In the response to these proposals, the Association drew attention to the unsatisfactory piecemeal approach: -

"Local authorities are being asked to tackle, firstly, the problems of Airey dwellings; secondly, six more PRC dwelling types; thirdly, the Smith houses (arrangements to be announced); and fourthly, six more types of PRC houses are being studied. Individually, the problems are large enough, but the cumulative effect is far more serious, and if presented together, would undoubtedly have affected the local authority response. Moreover, the Association has identified many further types of non-traditional houses, which are not of the PRC type, which the Government have yet to agree to examine.".

We then went on to outline the likely result of this report and the fact that there were already known to be many defective types of industrialised dwellings from this period.

5.5 The Government proposals to safeguard the position of private owners is discriminatory and unsatisfactory in many respects. We do, of course₁ wish to see sufficient resources devoted to disrepair in the private sector as the long term consequences of under-investment in this area would in any case fall upon local authorities. However, the imposition of statutory rights to a repair grant, or repurchase of defective dwellings by local authorities in some cases, merely pre-empts resources from other areas which may be every bit as needy; and adjacent public sector dwellings receive nothing at all.

5.6 The 'proposals for assistance' in respect of PRC dwellings do, at least, represent Government recognition that defective types do exist (something that was resisted apart from Airey dwellings for a long time). As yet, we have been unable to persuade the Government to take comprehensive research into defective types of 'non-traditional' and industrialised dwellings. There are certainly known defects in many non-PRC 'non-traditional' dwellings, and many defective types of industrialised dwellings apart from Bison which the Government have now acted upon.

5.7 The DOE wrote in October 1983 (51) to advise local authorities which own flats and houses built in the Bison Wall Frame system that they should take steps to satisfy themselves, if they have not done so already, that these buildings do not have certain specific defects which may present a safety risk. The letter had been sent as a result of the recent public concern about the safety of these buildings. In the letter, the DOE state that in the light of this concern, and as a precautionary measure, they are collating and reviewing reports of failures in flats and houses of this type.

5.8 The DOE's work "suggests that certain defects, although they may be infrequent, could lead to failures which, in exceptional circumstances, could present a safety risk.... Such failures could occur, in particular, where, because of shortcomings in the original specification, or the manner in which it was executed in manufacture or on site:

(a) no effective mechanical connection is made between load bearing wall and floor panels, and/or the bearing of floor and bedding of wall panels is inadequate, and/or the load bearing walls are not effectively restrained by buttress walls or spandrel panels;

(c) ties between the inner and outer leaves of external wall panels are lacking altogether, are insufficient in number per panel, or are of unsuitable material;

(d) inadequate cover or the presence of chloride has led to corrosion of the reinforcement and consequent spalling of pieces of concrete, in particular from external wall panels;

(e) pieces of exposed aggregate, used as a wall finish, are not adequately secure.

5.9 The DOE have asked local authorities to let them have details of appraisals of Bison dwellings which they have undertaken or have in mind, and details of any steps taken or proposed to eliminate safety risks. The DOE have also requested local authorities to make available the results of any appraisals to those who have bought, or may consider buying, from them flats or houses of the Bison design; and, where practical, to include their properties in any appraisal made by the authority. The DOE have also suggested to local authorities that they might find it useful to consult with other authorities that own buildings of this type so that information on methods of inspection and repair can be exchanged, and have offered to assist in the exchange of this information.

5.10 It is not yet clear what action might be proposed by the DOE in respect of Bison dwellings, nor if any assistance will be given to owners. Nevertheless, the DOE letter puts the onus for assessment largely upon the local authorities themselves and indicates, once again, a special concern for any private owners.

6.1 The cost of remedial works is extremely difficult to quantify. The variety of systems and associated problems means that it is very difficult to give more than a few 'pointers' to the type of work being undertaken and the costs involved with that work. For our First Report (30) we were better able to construct an average unit cost as whilst there were a similar number of systems, problems were more uniform, and being all low rise housing were not complicated by high and medium rise built forms.

6.2 There have been attempts to aggregate costs for one or two aspects of the problem. In 'Roof' (61), Roger Critchley, apparently drawing on experience from the National Association of Bison Tenants (NABT), estimated the cost of dealing with Bison flats at "over £1.4 billion". However, we feel, in the short or medium term, that this estimate is too high. Certainly, there are examples of refurbishment costing up to £20,000, and in some cases the cost of demolition and replacement (where the decision has taken other factors into account) is much higher. However, some authorities have managed to carry out a series of minor repair works, some of which are financed by revenue budgets, and more difficult to quantify.

6.3 The cost of asbestos removal from dwellings (mainly) and other industrialised building has been put at £1 billion by Building Design (62). This gave details of expenditure on asbestos of over £100m by just four London boroughs. Member authorities have also confirmed to us that the cost of dealing with this problem alone is running into hundreds of millions of pounds and it is fairly common to find the cost of tackling one scheme alone exceeding £1million. One London Borough which has carried out the most extensive surveys has found asbestos in 10,728 dwellings in half of its housing stock. The average cost of removal has been £1000 per dwelling. The likely cost for this London Borough so far is therefore £10m, and if the total dwellings affected rises to 20,000, as might be expected when the survey is complete, the cost could rise to £20m.

6.4 Perhaps the easiest identifiable single element is the cost of demolition and replacement. We estimate that there are already 10,000 units of accommodation demolished or scheduled for demolition. Assuming an average cost for this work, and attendant costs of 'home loss' and other payments of £30,000 per unit, this alone produces a sum of £300 million.

6.5 Remedial costs for the various works are more difficult to estimate, but it is possible to construct some average or typical costs based on responses from member authorities:

A number of other costs, such as re-asphalting walkways, repairs to external staircases and walls following differential movement, settlement to floor slabs, roof slab shrinkage, concrete lintel failure, are more difficult to average.

Some of these costs, such as repointing of sealant around window frames, which has to be redone at intervals, due to the action of the weather and differential movement, is seen as a revenue cost and not separately budgeted.

Again, some items are difficult poses. These include, stiffening the structure, or elements of it like the floors; improving roof fixings to the framed structure; roof wind bracing; and dealing with premature rotting of timbers due to water ingress over a period of time. Indeed, one member reported a cost of £2,000 per house for treatment and renewal of structural timbers, but there is a wide range of problems affecting window frames, door frames, porches, and spandrel panels, largely due to poor detailing and lack of watertightness due to differential movement.

6.6 In many cases a high or low rise system suffers from more than one of the above problems, though not necessarily at the same time. It therefore seems reasonable to assume an average cost of around £5,000 per unit, bearing in mind that for some types the cost of replacement will be much higher, whereas there are others as yet performing quite well. Assuming 750,000 to 1,000,000 industrialised dwellings (see para 3.5), it is possible that the total cost of repair and replacement in the medium term will be £3,750 to £5,000 million. In the longer term, the potential life expectancy must still be in doubt and further works, perhaps more drastic, may yet be needed.

6.7 Revenue costs are even more difficult to estimate and generalise about. However, consideration of several factors leads us to believe that the assumption of an average cost of £5,000 per unit is not unreasonable, and may even be an underestimate when revenue costs are added, bearing in mind that they are continuous.

6.8 Revenue costs associated with demolition are very high indeed. Firstly, the debt has to be repaid long after the dwellings are demolished and rent income has ceased. An example illustrates the point.

However, the cost must then be added of building new dwellings to rehouse those displaced. A further substantial loss is then incurred as the income from rent is (for, say, at least the first 10 years) much lower than the cost of repaying the loan on rebuilding costs.

6.9 It must be borne in mind that about 80% of housing authorities no longer receive any form of subsidy towards existing or new loan repayments.

6.10 A further (unsubsidised) revenue burden is the higher maintenance cost associated with industrialised dwellings and high rise developments in particular. However, even greater costs flow from the social consequences of these forms of development, and these will include additional management costs, lighting and security measures, clearing and refuse disposal.

6.11 The Association therefore believes that the Government should accept more responsibility for the schemes which it helped to appraise and design, and to promote and impose upon local authorities.

- increase HIP allocations to enable housing authorities to finance remedial and replacement schemes, and not at the expense of other necessary housing activity

- provide an adequate subsidy to offset the burden of loan charges on the capital costs of remedial works; demolition costs; compensation costs

7.1 Industrialised methods were developed to supplement the traditional building industry to meet new and higher levels of demand. This phase was similar to the late 1940's when non-traditional’ housing was developed to meet the post-war needs. That led to record completions and especially high output in the public sector (see earlier report "Defects in Housing Part 1 - Non-Traditional Dwellings of the 1940's and 1950's"). The housing progress was not sustained, however, and a new backlog of housing problems, particularly unfitness and disrepair in the older housing stock which necessitated large scale slum clearance activity, was beginning to emerge.

7.2 In the early 1960's, the scale of the new housing problems became all too apparent and Government launched housing programmes with exceptionally high housebuilding targets. The public sector was seen as the main vehicle for this drive and would provide the rehousing for the occupiers of houses in slum clearance programmes. Industrialised methods were therefore promoted by Government to rapidly expand the housebuilding industry and meet targets of up to 500,000 new homes a year. The public sector, which would be meeting basic housing needs, often with large scale redevelopment and high density schemes, would be especially suited to use of the new methods.

7.3 The 1956 Housing Subsidies Act provided the financial framework for the development of high rise and high-density schemes. The 1961 Housing Act continued with this subsidy system and local authorities were encouraged to design schemes with financial advantage in mind. This continued until 1967 when a new Subsidies Act abolished extra subsidy for high rise developments.

7.4 The Government gradually increased pressure upon local authorities to adopt industrialised methods. This was done in a number of ways:-

(iv) the system of local bye laws was replaced by a national scheme removing 'irritating impediments' being put in the way of schemes by some 'over zealous' authorities. Local authorities were urged not to make changes to standard plans and layout arrangements;

(v) the Government set up the National Building Agency and established MHLG regional offices to provide a series of local authority advisers to promote industrialised methods and provide help and guidance in the choice of sites, system, dwelling type, contract organisation and procedures;

(vi) local authorities were advised not to appraise the systems and methods they used, but to rely upon the Ministry and NBA, who later introduced formal appraisal mechanisms.

7.5 Government influence in housebuilding, through its departments and agencies, was direct and pervasive. Programmes were agreed, not only in terms of the numbers to be built, but the methods to be employed, the type of scheme adopted, and contractors lined up with agreed prices. Authorities 'co-operating’ received higher allocations and were given priority. Essentially, if local authorities wanted a substantial housing programme, they had to accept what was determined for them and relied on the judgement of Ministry and NBA officials. Local authorities were, of course, not blameless and were generally compliant partners and, in some cases, enthusiastic pioneers of new methods.

7.6 Appraisal certificates were issued in respect of 89 systems, although all systems in general use were also appraised by the NBA. The issuing of a certificate, however, whilst intended as a guarantee that the system was "sound and suitable for a 60 year loan sanction", has now been found to be deficient and some 'appraised' schemes are now known to be very defective. This raises very important questions as to the liability, not only of the NBA (now wound up), but the Government itself.

7.7 The building industry had to use industrialised methods to extend output beyond the limitations of traditional building. New materials could be used and both on-site and off-site prefabrication enabled greater use of unskilled labour. Mechanisation was developing coincidentally and the new schemes were also well suited to new architectural conceptions.

7.8 The Government departments also collaborated with builders and manufacturers, encouraging them to produce systems and components, and suggesting alterations etc. Developers were also able to agree levels of output and be put in touch with authorities requiring schemes of the type offered. National and regional prices were also negotiated.

7.10 Industrialised building was generally not cheaper than traditional construction except in the most favourable circumstances of high levels of output with a continuous programme. Decline of industrialised building was inevitable when the housebuilding programme was reduced by Government and special subsidies removed. By the later 1960's, disaffection was already growing, especially with high rise forms and the disaster at Ronan Point sealed the fate.

7.11 The defects problem is very widespread and has affected low, medium, and high rise forms of construction. The defects described in section 4 are not necessarily a function of industrialised methods but are certainly more prevalent in this type of construction and may also be attributable to the built form - which is determined by the method employed.

7.12 Dealing with virtually all of the problems has been very expensive, but their nature is varied. Cutting new expansion joints, or dealing with spalling concrete are obviously major structural problems, whereas, replacing mastic sealants may be necessary as a continuous maintenance operation. In our assessment, we have largely ignored the continuing maintenance burden, which is generally accepted as being much higher for this form of construction and concentrated on remedial works schemes, which are generally capitalised. Nevertheless₁ in deciding the future of schemes, local authorities will obviously have regard to longer term maintenance costs as well as other problems which determine whether the schemes are acceptable places to live, including associated management costs.

7.13 This study is of necessity limited and cannot hope to be fully comprehensive. We therefore believe that a more thoroughgoing study is necessary which cannot only quantify the problem of defects in greater depth and detail, but can also assist local authorities to determine appropriate schemes of remedial works. Bearing in mind Government involvement with these schemes in the first place, we believe they now have a responsibility to assist in this way. It is quite possible that remedial works schemes, which are often costing more than the original building works, may themselves prove defective in years to come unless a co-ordinated programme of evaluation is set up.

7.14 It is quite apparent that the initial appraisal was inadequate, prepared in haste to avoid slowing down the progress of political initiatives, and with no follow up assessment in use. Indeed, records of the various types, including construction details are extremely difficult to obtain and there was evidently no intention of any post-assessment. Experimentation was therefore boundless, with no attempt to control, monitor, and learn from that experience.

7.15 The cost of dealing with the defects problem is obviously difficult to quantify. Nevertheless, judging from the regularity of which certain items appear for different types and systems, it seems that the average unit cost will be around £5,000. This allows for the fact that some schemes are, as yet, performing well whereas others have been the subject of most extreme and drastic action. The total cost could therefore be up to £5,000m. Bearing in mind that 10,000 dwellings have already been demolished at a cost of £300 million, and the number of authorities with current remedial works programmes of between £10 million and £50 million, our estimate is thought to be fairly sound.

7.16 Capital expenditure must obviously be accommodated within housing capital allocations (HIPs), but these have been substantially reduced by Government in real terms since 1979. Further reductions are also planned for 1984/85 and 1985/86 (72). It seems to us, however, that expenditure should be geared to enable the deterioration of the public stock to be effectively dealt with and to prevent further, and more costly, decline. It should be borne in mind that the older private housing stock condition which also has to be accommodated within HIPs is also in need of increased provision and the provision of new public sector housing is at an extremely low level.

7.17 The cost of industrialised building problems is also high in revenue terms. Increased management and maintenance costs are very significant, but considerable extra costs are increased in loan charges on the cost of remedial works, demolition costs, and compensation payments. Where houses are demolished, loan charges will, in general, continue to be met for a further 45 years or so without the benefit of rent income. It should be borne in mind that around 80% of authorities no longer receive an Exchequer Subsidy to their Housing Revenue Account.

7.18 The Association welcomes the fact that provision is to be made for private owners of non-traditional dwellings, but believes the Government should recognise its responsibility for all dwellings which are now defective, and were produced as a direct result of previous Governments' actions, and compensate public owners accordingly. Local authorities should not be expected, nor can they afford, to meet the additional capital and revenue expenditure within existing resources.

7.19 The Association is concerned that the possibility of successful legal action to secure redress in respect of design errors and bad workmanship has, if anything, become more limited recently. It is hoped that the present review of the law in this area will lead to an improvement of the client's position.

7.20 Previous experience in both the 1940's/1950's period of 'non-traditional’ construction and the 'industrialised building' of the 1960's and 1970's has demonstrated the grave weaknesses of stop-go investment patterns in housing and construction. In both cases, a backlog of housing need has had to be catered for by new untried designs, materials and techniques. This was essential, as the traditional industry was constrained by limits on the availability of skilled manpower, traditional materials, and existing patterns of organisation. Expansion of this order can never hope to be successful, and can only hope to succeed where it is gradual and controlled and development monitored and evaluated, in use, over a substantial period of time. With the current decline in housing investment, and the emergence of new and growing housing needs, we again seem to be moving towards another period when the same choice will face us - sudden expansion of output with new untried methods and materials, or unacceptable housing conditions. That can only be avoided if our problems are recognised now.

7. Planning Bulletin No 2 "Residential Areas – Higher Densities" MHLG Circular 46/62 (1962) HMSO.

13. Report of Working Party on the Costing and Management of Local Authority Housing HMSO 1964.

25. Collapse of Flats at Ronan Point, Canning Town - Report of the Inquiry 1968 HMSO.

26. Flats Constructed with Pre-cast Concrete Panels - Appraisal and Strengthening of Existing High Blocks MHLG Circular 62/68 1968.

27. Appraisal and Strengthening of High Blocks Government Grant MHLG Circular 29/70 (1970).

28. "Industrialised Building". Paper by A W Cleeve Barr to AMA Conference September 1963.

30. Defects in Housing Part 1: "Non-traditional Dwellings of the 1940's and 1950's" published by the AMA 1983.

32. "A Social History of Housing 1815-1970", John Burnelt, University Paperback, 1980.

33. "High Flats in Local Authority Housing in England and Wales Since 1945", E W Cooney in "Multi-storey Living", Anthony Sutcliffe Ed., Croom Helm 1974.

34. The Politics of Mass Housing in Great Britain 1945-1975, Patrick Dunleavy, Clarendon Press 1981.

36. Industrial Building Development. Address by the Rt. Hon. Geoffrey Rippon MP, Minister of Public Building and Works to the AMC Council Meeting, July 25 1963.

37. Parliamentary Written Answer, Sir George Young MP, Hansard 7 November 1983.

41. Non-traditional and Systems Housing Bulletin, Scottish Local Authorities Special Housing Group.

42. The Comprehensive Industrialised Building Systems Annual 1965. House Publications Limited, London.

44. A Decade of British Housing 1963-73. Ed. David Crawford. Architectural Press Ltd, London 1975.

45. The Post-war Housing Experience - Housing in Britain, John R Short, Methuen 1982.

50. Circular 6/83, "Airey Dwellings", Department of the Environment. February 1983 HMSO.

51. DOE Letter to Local Authorities, "Bison Wall Frame Flats and Houses", 5 October 1983.

54. An Investigation into Difficult to Let Dwellings Vol 2 Case Studies of Post-war Estates. DOE Occasional Paper 4/80, HMSO 1980.

55 An Investigation into Difficult to Let Dwellings Vol 3 Case Studies of Pre-war Estates. DOE Occasional Paper 5/80 HMSO 1980.

56. Reducing Vandalism on Public Housing Estates, DOE HDD Occasional Paper 1/81. S Wilson, HMSO 1981.

58. Priority Estates Project 1981 - Improving Problem Council Estates DOE HDD, HMSO 1981.

59. Priority Estates Project 1981 - Improving Problem Council Estates : A Summary of Aims and Progress, DOE, HMSO, 1982.

63. Building Systems, Industrialisation and Architecture, Barry Russell, John Wiley & Sons.

64. GLC Housing Management Committee. Report of Special Sub-Committee on Major Technical Problems. Chairman Mr T Judge 1976.

69. Industrialised Building Vol II. RME Daimont. Architect and Building News 1965.

(a) choice of sites: consultation on the suitability of individual sites for industrialised building (Ministry/Agency);

(b) choice of system: advice will be offered on systems available and suitable for the authorities' requirements of density, range of family sizes, etc. (Agency);

(c) advice on dwelling-types, layouts etc.: the usual Ministry Regional Architect service to groups and individual local authorities will concentrate particularly on schemes in the drive; this will be done in consultation with the Agency so that choice of system, plan types and layout are effectively related (Ministry/Agency);

(d) organising phased programmes: the Ministry will be continuing and expanding their services to consortia, and will also be ensuring that schemes of individual authorities are grouped ad hoc into co-ordinated programmes (Ministry);

(e) the Ministry and the Agency will co-operate to secure a satisfactory flow of work for each successful system. In addition, specialist help will be forthcoming from the Agency’s project planning engineers, who will also be available to advise authorities on methods of programme control (critical path, network analysis etc.). They will provide a full or partial service on a fee basis where required (Ministry/Agency)

(f) statutory procedures: advice will be available on the choice of statutory procedures for land acquisition etc. Priority will be given to the Ministry's handling of schemes forming part of the drive. Stickers will be supplied to identify letters relating to these schemes (Ministry HQ);

(g) other procedures and consultations: the Ministry will help where appropriate on consultations with local planning authorities, statutory undertakings etc. (Ministry):

(h) in a number of cases where authorities are extremely short of staff or pending the recruitment of staff for working parties about to bc established by consortia, the Agency can provide full or partial architectural services, if required. Where these are provided on a scale beyond normal advisory services professional fees will be charged (Agency);

(i) in special cases the Ministry or the Agency will carry out demonstration or pilot projects (Ministry/Agency).

(a) they use the system in accordance with any conditions set out in the appraisal certificate;

(b) they make application for any necessary relaxations of Building Byelaws or Building Regulations (the appraisal certificate will specify these);

(c) they nominate a professional officer or adviser to take full responsibility for site supervision;

(d) in the case of buildings above four storeys, they check structural calculations as necessary under the Building Byelaws or Building Regulations.

(a) The local authority, on the advice of their own architect, or a consultant employed by them, prepare a design brief.*

(c) The architect studies a short list of systems on offer to ascertain how far each can meet the main points of the brief, and what the comparative costs are likely to be (on the basis of the agreed prices).

(a) the total number of dwellings, and the approximate proportion of dwellings of different sizes;

(b) the general form of development i.e. whether in flats, maisonettes, houses, or a mixture in certain proportions;

(c) the way in which the layout will fit in with the general road pattern and development form of the town ; and the method of providing for segregation of vehicles and pedestrians;

(g) any special requirements for multi-storey buildings, with regard to lifts, refuse chutes, plumbing, drying areas and similar matters;

(h) details of site conditions, including levels, nature of subsoil and liability of subsidence, site investigation report (in the case of multi-storey buildings), trees to be retained, services available, etc.;

(j) building byelaws or building regulations, relevant B.S.S.'s and C.P.'s to be complied with, etc.

(e) The sponsor collaborates with the local authority's architect on the application of his system to the particular scheme.