The SF1 System and the Elgin Estate

Anthony Walker

SF1 was a high-rise housing system designed by a group led by John Davidson in the London County Council (LCC) Architects' Department and was intended to bring industrial standards of fabrication to the housing market at a time when there was enormous pressure to provide more housing and to do it quickly.

Three estates were proposed as a first contract: the Watney Estate in Hackney; Tindal Street, Lambeth; and the Elgin Estate in Westminster. In the event only four blocks were built, two on the Watney Estate and two on the Elgin Estate. The LCC approved the purchase of the Walterton Estate, which includes the Elgin Estate, from the Church Commissioners on 16 December 1952. By 1963 the long leases of nearly 800 dwellings had expired and reverted to the Council's control as freeholder. These dwellings were let in about 2500 separate tenancies and occupied by at least 7000 people but most of them were in a very poor condition after years of neglect and had a probable life of about ten years.

The LCC Architects' Department had been interested in prefabricated cladding systems for some time. Figure 1 shows an extract from a handwritten document outlining some of the motivation which led to their development. Of the proposed blocks, those that were actually built had a floor layout based on four flats grouped round a central concrete core with a steelwork frame on a 13ft 4in (4.06m) grid but the system was intrinsically flexible and could apply to a wide variety of plan forms. The cladding units were designed to a 6ft 8in (2.03m) module either with or without a window, and corners were clad with separate asbestos cover units set at a 450 angle. The cladding panels were of a composite construction which it was thought would require minimal external maintenance for at least 20 years. They were assembled in three-storey units, fully glazed and with internal finishes ready for final fittings and decoration. An outer skin of 2.286 mm glass reinforced plastics material (GRP) was filled with lightweight concrete reinforced with weldmesh, and separated by a layer of foam to allow for movement. A vapour barrier was provided and the interior finished with plaster. The edges of the panels had were reinforced with hollow steel tubes welded to corner brackets and windows were of aluminium in a design based on car manufacturing techniques with radiused corners to allow the use of continuous neoprene gasket glazing beads. The cladding was to be produced commercially to designs by the LCC and for which a patent had been applied. One major problem to be overcome was the question of fire spread and the architect, John Davidson, proposed exclusive rights to a supplier for a limited period while a solution was sought, with the right to a break if this was not achieved within that period. In 1962 he confirmed that in order to test the panels properly it would be necessary to manufacture four or five at the LCCs Wandsworth depot and to erect them on a steel frame. The whole structure would then be taken to Borehamwood for fire testing (1). On 9 May it was resolved by the Housing Committee to spend £2000 from the maintenance account on the patenting , production and testing of these panels but by July there was some disappointment with the fire-retardant performance although Industrial Exchange Co. had written to say that it still believed that it would be possible ultimately to achieve the desired Class 1 certificate.

There were discussions with other organizations including Jablite Plastics, Castrol (Tensile Products) and British Industrial Plastics, but all except Mr Jablonsky of Jablite considered that the investment for development of the panel would be of the order of £75 000 - £150 000, a very substantial sum at that time. Nevertheless the plastics panels were thought to be essential in reducing the weight of the cladding and so reducing the cost of the frame and the foundations as well as speeding construction. It was proposed to continue discussions with Industrial Exchange but also to meet the Cape/Mickleover organization. Mickleover had already manufactured some British Rail relay cabins and gone on to develop a two-storey version using a steel frame for a telephone exchange which had been erected in the Bakelite works at Tyseley. The technology had also been used for laboratories in the Antarctic. The working party set up to carry out these investigations visited both companies and reported on 18 October 1962. The main difference between the two was in their approach to the inhibition of flame-spread which Industrial Exchange suggested could be achieved by using mechanically controlled processes for which fire tests at Fibreglass were reported as promising but details were not disclosed at that stage. Cape/Mickleover on the other hand was able to demonstrate its manufacturing processes at its plant at Colindale where a hand operated depositor was used together with manual rolling-out in the moulds. The conclusions drawn from subsequent fire tests carried out at Borehamwood were that the classification standard required could only be achieved by pressurized methods of manufacture (Industrial Exchange) which would give a denser and more uniform laminate. The working party proposed that an agreement be drawn up with Industrial Exchange to allow a full-scale fire test to be carried out. In April 1963 samples of the GRP panels were given by Industrial Exchange to the LCC Scientific Adviser who carried out tests including an assessment of their weathering and reported to the architect in July that year (2). Samples were also submitted to Yarsley Testing Laboratories who reported in July 1963 that the material could be classified as Class 1 - very low flame spread.

Industrial Exchange was busy marketing the system and arranged a conference in June 1963 in London for other city architects as well as members of the LCC. In July, William Fischbein, later to be managing director of Indulux, wrote to Kenneth Campbell, LCC's chief housing architect, reporting on progress and stating that the enquiries they had received as a result of the conference indicated that they might indeed recover the heavy investment they had made. From his letter in August
to John Davidson it was clear that considerable progress had been made with detailed designs being prepared by the LCC Architects' Department (3). In September 1963 Hubert Bennett, Architect to the LCC, confirmed in confidence to the chief engineer that a consortium was being formed to carry out the building work. Members were FG Minter, Redpath Brown and Industrial Exchange (soon to become Indulux) and that the former was calculating a price.

Promotion at the Building Exhibition
The SF1 system was promoted at the Building Exhibition with a press release suggesting that a normal seventy-week building contract could be reduced to 40 using this system. It also confirmed that Fibreglass Ltd and British Resin Products (associated with Indulux) were involved. The fire tests were conducted using a pressure-produced sample from Indulux and reports 2586/2995 were published in July 1964. The details of the panels tested differed substantially from those actually used. In particular a continuous neoprene tube joint which it was anticipated would be kept under compression was used in an early test. The actual installation had a simple polysulphide seal between the adjoining panels.

In October 1964 the LCC Housing Committee was informed that steel framed buildings were being investigated using lightweight cladding for maximum economy. Preliminary costings had been obtained from Minter and it was anticipated that formal approvals would be sought for sites at Watney Estate and Tindal Street before the end of the year. In the meantime approval was sought for the first two blocks, each of 22 storeys, which would be erected at Walterton Road, Paddington (the Elgin Estate). In a concurrent report (Hg 768) permission was sought to negotiate an offer from FG Minter for the construction of three estates: Walterton Road, Paddington; Watney Estate, Hackney; and Tindal Street, Lambeth before the end of the year. There would be about 700 dwellings in total and the large contract was necessary to justify the investment in plant which would be required. The proposals were approved and construction started on the Elgin Estate.

The first cladding panels were erected on 24 November 1966. Those for the first block were manufactured in America by the Molded Fiberglass Company under the supervision of Indulux since this was the only place where suitable experience of large machine-matched moulding techniques was available. By the time panels were required for the subsequent blocks production was underway at Indulux's works at Luton. By July 1967 Mr Chapman of the LCC was under pressure to submit an improved programme (5) and that autumn Horace Cutler, chairman of the Housing Committee, was able to say that the fabric of a second block would be complete by end-October with final completion being programmed to allow occupation by the spring of 1968.

Sadly, there was not to be a happy ending. The Elgin Estate buildings went through an unhappy period during which the two blocks named Hermes and Chantry suffered badly in a fire. It was reported that burnt-out flats were left unrepaired and undoubtedly little or no action was taken to deal with the known risks from disintegrating asbestos. In 1984 a report was commissioned by the Greater London Council (GLC), successor to the LCC, from Max Lock Easton Perlston & King on the condition of the Watney Estate including the two tower blocks. The use of asbestos was found to be widespread and it was noted from discussion with the GLC that the sprayed fireproofing had become very friable and would have to be removed. A similar situation prevailed at Elgin and eventually Walterton & E gin Community Homes purchased the whole estate with an allocation of money from Westminster to demolish the tower blocks as the only realistic means of dealing with the problems.
After this chequered history, the GRP panels were found to be generally sound and without cracks. There was evidence of repairs which it was assumed were carried out following a previous report by the GLC Scientific Branch Buildings Report in October 1975. The GRP skin had generally separated from the concrete filling allowing up to 6 mm flexing. The mastic between the panels was sound but had hardened on the surface and lost adhesion to the panels in many instances. It was understood that there had been few cases of water penetration. The fixings were opened up internally and the work was generally in accordance with the record drawings except where an asbestos separating board had been substituted with a tape to separate the RHS (rolled hollow section) framing and the panels. There were some signs of deterioration of the steelwork near the edges which might have been caused by water penetration or condensation.

It is apparent that the main impetus to developing the system was to counterbalance the shortage of building resources and professional manpower. Derek Caswell, a GRP consultant at the time, comments that even when Indulux had the system ready to use an interview with Harold Wilson, then a cabinet minister, was needed before orders were placed which implies that there were serious misgivings about the system which delayed its acceptance. The exterior certainly did not live up to the anticipated maintenance-free finish originally specified, but the real problem lay not with the cladding but in the amount of asbestos used internally and the possible long-term fixing problems, both of which would have necessitated the buildings being more or less taken to pieces in order to achieve an acceptable solution. Mike Webb,
however, writing in 1969 soon after the buildings were completed, considered that they offered a wholly new and potentially revolutionary form of construction (6). The use of GRP for the exterior panels undoubtedly played a major part, allowing cost savings to be made on the structural frame and the use of three-storey cladding units. Whether or not their loss is regretted for their architectural merit, they are certainly worthy of a place in history for their technical innovation. It was a brave concept which in other circumstances might have received accolades rather than censure.

References
(1) Memorandum, 8 February 1962.
(2) Memorandum from the LCC' s medical officer of health to the architect. Weathering was noted as causing some loss of gloss, rain-spotting and blistering, also reducing scratch resistance to about a third of its original value. It also caused appreciable yellowing. 17 July 1963.
(3) Letter, 15 August 1963.
(4) Report from the Architect to the Housing and Town Planning joint Committee, 1 October 1964.
(5) Notes of a discussion between the Housing, Architects' and Valuation Departments, 20 July 1967.
(6) Mike Webb, Country Life, 'Architecture in Britain Today', 94,1969.