Prefabs in the United Kingdom

The first prototype to be unveiled was the motor industry contribution, a steel panelled experimental temporary bungalow called the Portal after the minister of works, Lord Portal. With a floor area of 616 square feet (57.2 m²), and an estimated cost of £600 constructed, and £675 fully furnished.[15] It included a prefabricated slot-in kitchen and bathroom capsule, that included a pre-installed refrigerator. The proposed rent was 10 shillings (50p) a week for a life of ten years.

Airey houses in Seacroft, Leeds

Developed by Leeds based construction magnate Sir Edwin Airey, it was easily recognisable by its precast concrete columns and walls of precast shiplap concrete panels.[16] Due to its variation of design, available with a flat or pitched roof, and with variations for rural or urban sites; it became one of the most prolific of the permanent designs.[17]

Developed and constructed by Taylor Woodrow, the Arcon was an asbestos-clad variant of the Portal, with the same prefabricated kitchen and bathroom capsule. It had a longer life, but also came with a higher cost of construction.[3] The later rolled top roofed Arcon Mk5 was developed by Edric Neel.[18] 38,859 were constructed through the programme.[6]

The two bedrooms were approximately the same fairly generous size with picture windows which included an opening window. The kitchen was fitted with steel cupboards, drawers and an integral sink unit. A side door entered directly into the kitchen. A gas copper, gas oven and hob, and a fitted-in gas fridge were incorporated into the inbuilt steel kitchen units. A drop-down wall-fitted table adjacent to a built-in larder was opposite the built-in units. The lounge had an open coal fire, the heat from which heated a back boiler, thus giving "free" hot water. The bathroom had a full-size bath and fitted steel cupboards. There was a separate toilet. The lounge and both bedrooms had steel built-in cupboards and drawers. Arcons were so well fitted (in Debden, Loughton, Essex) that the only furniture necessary were beds, kitchen chairs, lounge seating and floor coverings. Chain-link fencing, a gate and a coal shed built with corrugated steel from Anderson shelters and brick front and rear walls was also provided. Gardens were of sufficient size to grow vegetables, and many early residents quickly erected a chicken run.

The AIROH (Aircraft Industries Research Organisation on Housing) house was a 675-square-foot (62.7 m²), ten tonne all-aluminium bungalow assembled from four sections, each to be delivered to the site on a lorry, fully furnished right down to the curtains. The proposed rate of production of complete houses was to be an incredible one every twelve minutes. This was possible because the completely equipped and furnished AIROH could be assembled from only 2,000 components, while the aircraft it would replace on the production line required 20,000. The parents of future Labour Party leader Neil Kinnock were allocated an AIROH, on which he commented:[3]

It had a fitted fridge a kitchen table that folded into the wall and a bathroom. Family and friends came visiting to view the wonders. It seemed like living in a spaceship.

Although impressive, the AIROH by 1947 was costing £1,610 each to produce, plus costs of the land and installation. However, as the design was so easy to produce, 54,500 AIROHs were constructed.[19]

Cornish houses in Barnsley, South Yorkshire.

Designed by A Er v.senthil and R Tonkin for the Central Cornwall Concrete & Artificial Stone Co., they are also known as Cornish Type and Selleck Nicholls & Williams houses. The houses came in type-1 and type-2 designs, incorporating variations of a bungalow, two storey semi-detached and terraced layout with a medium pitched Mansard hipped roof.

The first floor is PRC clad over a single-storey concrete frame, while the type-1 house has the Mansard roof over timber trusses. Internal walls are made of PC wall block or brick. So successful was the design, 30,000 Cornish Unit houses were eventually constructed.

However the roofs and wall insulation incorporated asbestos, while the wooden frame-based construction means that as the concrete decays the two parts tend to separate, resulting in large amounts of internal cracking. The major defects are:[20]

• Horizontal and vertical cracking of PRC columns
• High rates of carbonation and significant levels of chloride in PRC columns
• Cracking of first floor ring beams

Hawksley-built bungalows in Letchworth, 2014

A W Hawksley Ltd of Hucclecote were formed in 1940 by the Hawker Siddeley group owners of the Gloster Aircraft Company to build the Albemarle aircraft designed by Armstrong Whitworth. Post-Second World War, its parent company Hawker Siddeley kept it open to supply prefab houses and bungalows to the MoW. After their MoW work finished, they continued exporting their buildings to Australia, New Zealand and Uruguay into the 1960s.[21] Their designs included:[22]

• BL8: an aluminium-clad timber-framed bungalow.[16]
• C2/C3: either a three-bedroom bungalow, or convertible to a government building such as a post office or doctors' surgery
• Hawksley House: a semi-detached or terraced house with 2–4 bedrooms based on the principles of the Swiss architect G. Schindler
• Hawkesley Single Storey building: a general-purpose building suitable for schools, offices, hospitals and village halls

An estate of 60 Hawksley bungalows was constructed in Letchworth Garden City in 1950–51. There are also similar houses in the Canley and Tile Hill areas of Coventry, however many of these have been demolished in favour of modern buildings for Warwick University.[23] As of 2014, the buildings are still maintained and occupied.

The company later developed an aluminium house for the Margaret MacMillan Memorial Fund, for use in tropical overseas relief missions.

Another designed by Sir Frederick Gibberd, the steel-framed design was privately promoted by John Howard & Company. A more industrial aesthetic design, and more adventurous in its use of innovative technologies. Asbestos cement cladding panels are clearly expressed with metal flashings over a base course of foamed slag concrete panels, with windows and doors fitting within the module set up by the cladding. Unlike the BISF, this house proudly displays its lightweight prefab nature, but there are also technical advances that set the Howard House apart, for example the precast concrete perimeter plinth that supports a suspended steel ground floor. Only 1,500 Howard Houses were built.[24]

Designed by Laing and Co., as they are poured in-situ into moulds type designs developed from 1919 onwards, they do not suffer the problems of many steel framed buildings. The rare Mk1 version had 8 inches (20 cm) thick solid no-fines clinker concrete walls, built in the period 1919 to 1928. The more common Mk2 version from 1925 to 1945 had cast in situ cavity walls, 3 inches (7.6 cm) thick inner and outer leaves with 2 inches (5.1 cm) cavity, usually finished externally with stone dashed render coat. Post-1945, the Mk3 version, which makes up the majority of houses, was modified to specification, and hence had cast in situ concrete walls, inner and outer leaves of 3 inches (7.6 cm) thickness separated by a 2 inches (5.1 cm) cavity, and reinforcement in both skins located in four horizontal bands above and below window openings.[25][26]

Designed by J C Tilley and manufactured by W. & C. French Limited Lecaplan came in two types, Type A were 2-storey terraced houses. Characterised with shallow pitch gable roof covered with concrete tiles. They have external walls of concrete panels throughout, or front and rear walls infilled with timber shiplap boarding. Type B were a later variant of similar profile but with an added entrance porch and exclusively concrete walling throughout. Of each type some 1600 were constructed between 1966 and 1971.[27]

Like the Laing Easi-Form, a cast in situ concrete form of construction, first used in 1952 but mainly in the period 1962 to 1981. With a solid cavity wall, the poured concrete substitutes for the inner blockwork walls of traditional housing. Solid wall types 225 millimetres (8.9 in) thick cast in lightweight concrete, rendered externally. Cavity wall types have an inner leaf of at least 100-125mm thick concrete.[25]

Designed by Czech architect Erwin Katona, who left Czechoslovakia in 1938 to move to the UK, the design is a two-storey precast reinforced concrete design.[28] The design was produced in Scotland by the Orlit Company, resulting in most houses being located in Scotland and Ulster.

On-site construction was based on a foundation which supported storey-high precast concrete columns at fixed intervals, supporting concrete beams fixed to the columns, resulting in a virtually monolithic frame. Faced externally with large concrete slabs, and internally with interlocking foamslag blocks. Internal partitions are constructed of breeze blocks finished in plaster, as is the foamslag internal cladding. The floors are constructed of precast concrete flooring units, with timber flooring on timber runners.[29]

Due to both the speed of construction and the quality of production, over time the PRC deteriorates, particularly at construction joints and junctions between components, with a gradual reduction in structural effectiveness. This resulted in the Orlit being designated as defective under the Housing Defects Act 1984, and hence a majority of mortgage lenders will not give any form of mortgage on them.

Grade II listed Phoenix prefabs in Wake Green Road, Birmingham

The Phoenix, designed by Laing and built by themselves as well as partners McAlpine and Henry Boot,[2] looked much like an AIROH with a central front door. It was a two-bedroom in-situ preform design with steel frame, asbestos clad walls and an innovative roof of tubular steel poles with steel panels attached. Like all designs, it came pre-painted in magnolia, with green highlights on frames and skirting.[30] Phoenix prefabs cost £1,200 each constructed onsite, while the specially insulated version designed for use on the Isle of Lewis in the Hebrides cost £2,000.[2]

Reema houses were built from large-scale (nominally single-storey height) precast reinforced concrete panels, themselves made in factories, before construction was enabled onsite. Reema houses came in two forms:

• Reema Conclad
• Reema Hollow Panel

Due to structural degradation and the use of asbestos in the wall and roof insulation,[31] both are difficult to obtain a mortgage on today. The Reema Hollow Panel is listed universally as defective after a Government-sponsored investigation and the subsequent Housing Defects Act 1984, while the Reema Conclad is often mis-recognised as a Hollow Panel.[32]

Swedish Timber Framed House at Shorne, Kent

Between September 1945 and March 1946, Sweden exported 5,000 prefabricated houses to the UK and 2,100 to France. The design was adapted by the MoW from a standard Swedish kit, with the all-timber houses arriving in flat sections, and then stored at the docks for allocation. In England and Wales this was often in small numbers to rural areas in support of farm workers. The first of these houses were built at Abbots Langley, Hertfordshire, in January 1946.[33] There are two basic designs: semi-detached houses with a single storey utility extension and semi-detached dormer bungalows. A pair of the bungalows at Auckley near Doncaster (Grid Ref: SE651012) have been listed by Historic England (their ref: 1392257).

In Scotland a slightly different style of house (without the single-storey utility extension) was erected in large estates in Edinburgh, Glasgow, Inverness and elsewhere.

The Tarran was designed by building firm of Tarran Industries Ltd. of Hull. A wooden frame designed bungalow,[4] over clad with precast concrete panels. 19,014 Tarrans were erected under the Temporary Housing act, but one- and two-storey variants were built in some numbers afterwards.[34]

The Tarran was designed by building firm of Tarran Industries Ltd. of Hull. A wooden frame designed bungalow,[4] over clad with precast concrete panels. 19,014 Tarrans were erected under the Temporary Housing act, but one- and two-storey variants were built in some numbers afterwards.[34]

Excalibur estate in Lewisham in 2013

Produced by the London-based Selection Engineering Company Ltd, the three versions of the Uni-Seco were largely erected in London and the southeast. A two-bedroom flat-roofed bungalow, it had a resin-bonded plywood timber frame with asbestos wall sections,[35] it was based on a military wartime office design. With dimensions of 23 feet 6 inches (7.16 m) by 19 feet 7 inches (5.97 m),[7] the first two versions included the MoW standard kitchen/bathroom service unit, plus a lounge; Mark 3s had a central entrance over the original side door.[36]

In 1943, Uni-Seco had appointed the Czechoslovakian émigré George Fejer as an industrial designer, who on a part-time basis helped out with their kitchen design. Fejer later worked with Arthur Webb and George Nunn at Hygena to create the UK style of fitted kitchen, based on the principles of the Frankfurt kitchen.[37] Approximately 29,000 Uni-Seco units were constructed. The Excalibur Estate in Catford, Lewisham, is the UK's largest residual estate of prefabs, presently consisting of 187 Uni-Seco bungalows,[38] but the demolition of all but six was announced in 2011.[39]

Unity Structures prefab, preserved at the Chiltern Open Air Museum

Unity Structures were a construction company based in Rickmansworth. Using common storey-level precast reinforced concrete panels, they produced various updated versions of their bungalow and twin-storey house variations. Using metal bracing within the cavity and metal joists connected at column joints, the PRC columns act as mullions. Copper straps tie the inner panel to outer PRC panel on earlier variants, while later the copper strap fixed to column holding just outer PRC cladding panels.

Although the design incorporates significant steelwork resulting in fair current structural condition, the concrete used in casting is decaying, and resultantly leaks chlorides. This results in internal staining through panel joints, and corrosion of the metal reinforcing and straps.

A Unity Structures bungalow originally located in Amersham is preserved at the Chiltern Open Air Museum.[40]

George Wimpey & Co., being a house builder, focused on both design but also speed and ease of construction. Their method used "no-fines" concrete, the composition of which used no-fine aggregates. Using huge reusable moulds, they were held in place as the concrete for the entire outer structure was poured in one operation. The ground floor was also concrete, while the first floor was made of wooden floorboards. Interior walls were a mixture of conventional brick and blockwork construction. Wimpey's design was particularly successful, resulting in many thousands built, and still occupied today.[25][41]

There are:

Hamish prefabs (types 1 and 2)

Duplex Sheath prefab

Bricket Wood Special prefab

Blackburn Orlit prefab

and even a pre-fabricated gem known as the Foamed Slag.

AIROH prefab preserved at the Museum of Welsh Life

Bristol has one of the largest remaining populations of prefab housing stock, which also remains one of the most diverse. A wartime production centre for aircraft, engines and explosives, it was easy to reach for Luftwaffe bombing, and hence had a large post-war need for new housing stock. There remain around 700 examples of Uni-Seco, Phoenix, Tarron and roll-topped Arcon Mk Vs. The stock diversity has resulted in English Heritage selecting 16 prefabs for Grade II listed building status.[18]

The Excalibur estate in Catford, London Borough of Lewisham is the UK's largest remaining estate of post-WW2 prefab houses, with 187 Uni-Seco wooden frame bungalows plus a flat-roofed prefab church. While residents fought to save the entire 187-unit estate, English Heritage wanted to save 21 examples, and the council, which still owns 80% of the properties, wanted the ability to demolish the whole estate. In September 2009, the Department for Culture, Media and Sport agreed to Grade II list six of the least altered properties.[38] Similar debates have resulted in the listing of 16 Phoenix prefabs in Wake Green Road, Hall Green in Birmingham;[5] and two in Doncaster.[38]

Approximately six prefabs have been extracted from site for preservation, including one AIROH at the Museum of Welsh Life at St Fagans.[1] An Arcon Mark V from Yardley in Birmingham is now preserved at the Avoncroft Museum of Buildings.[5]

Media related to Prefabricated houses in the United Kingdom at Wikimedia Commons

• AW Haksley Prefabs for Northern Ireland from archive of British Pathé
• New Style Buildings 1962 in Bethnal Green, London, from archive of British Pathé
• Lorry leaving the factory of AW Hawksley with an export house
• Reconstruction process on a Unity Structures Mk1 house (slide show)