The Orlit PRC House Construction
Construction Review of the Orlit PRC House
- Manufacturer: Orlit Ltd
- Czech Architect: Erwin Katona
- Number Built: 70,000
The type I & II Orlit PRC Houses were both built during the 1940s & 50s with a combined build count of around 17,000 properties in the UK.
The Orlit house is classified as Defective in England & Wales. (Repealed in Scotland).
The Orlit house is classified as Defective in England & Wales. (Repealed in Scotland).
The Orlit PRC House has a precast concrete frame structure, externally clad with 2 inch reinforced concrete hollow blocks. The individual sections of the frame were connected with high alumina cement joints. By the 1980s, it had been identified that this type of house was prone to structural weaknesses as a result of the degrading of the high alumina cement joints, often because of condensation. Accordingly, all over the country the houses were surveyed for structural safety, and usually demolished or subjected to extensive repairs & refurbishment.
Orlit PRC House
Orlit PRC Type I
The Orlit type I PRC Houses were built as bungalows & two storey semi-detached and terraced houses with a medium pitched hipped roof covered with tiles or a flat roof covered with asphalt or bituminous felt.
The external walls are constructed of PRC slabs throughout and this system was also used to construct flats.
Orlit PRC Type II
The Orlit PRC type II houses were also built as bungalows & two storey semi-detached and terraced houses with a medium pitched hipped roof covered with tiles or a flat roof covered with asphalt or bituminous felt. Hipped roof example was generally fitted with hanging tiles fitted to the gable apex.
The external walls are constructed of PRC slabs throughout and this system was also used to construct flats.
Orlit PRC House Construction Details
Orlit PRC Houses were generally built with a structural concrete frame which was clad in small precast reinforced
concrete panels. Orlit properties were constructed with both flat and pitched roofs.
The flat roof variant has a roof formed from solid concrete slab, whilst the pitched roof version requires no roof slab as was fitted with a traditional timber framed, supported on wall plates.
Secondary concrete beams used in the flat roof design however were still retained.
- Primary load bearing structure comprises of two bay, two storey precast reinforced concrete portal frames with cast in-situ joints in the beams and bolted connections in the precast columns.
- The floor and roof construction are carried by precast concrete secondary beams which span between the primary frames.
- The outer cladding and the inner blockwork of the external walls are connected with galvanised mild steel ties which span across the cavity.
- The external walls and internal cross walls provide overall lateral stability to the structure.
Click Here To View The Orlit House Image Gallery
Click Here To View Orlit Houses on Google Street View
Further information regarding the Orlit PRC House and including an in depth structural assessment can be obtained by purchasing report No 1983 from BRE Press bookshop.
The report provides a generic view of the main structural components with an in depth review of noted defects possible issues.
It should be noted that there are a wide number of build variations associated with this property type that are not mentioned here. However our aim is to hope provide a general insight into the structural composition of this property type.
Downloads
Structural assessment of Orlit properties Haringey
- Do you or have you ever lived in a Orlit property?
- Have you ever worked on or with this this type of construction?
- Please share your thoughts in the comments below.
Orlit Type I Frame 
Orlit Type II Frame
Responses