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 thick cast in lightweight concrete, rendered externally. Cavity wall types have an inner leaf of at least 100-125mm thick concrete. Orlit 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. 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. 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. Phoenix (THP) The Phoenix, designed by Laing and built by themselves as well as partners McAlpine and Henry Boot, 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. 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. Reema 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, both are difficult to obtain a mortgage on today. The Reema Hollow Panel is listed universally as defective