The Arcal House

The Arcal house is a form of system-built, non-traditional housing constructed in the UK between 1964 and 1970. Approximately 700 units were produced, primarily by Gee Walker & Slater Ltd, with designs attributed to G80 Developments Ltd. These properties form part of the wider post-war housing programme and are most commonly found within suburban estates.

An Arcal house showing typical rendered elevations and gable roof construction associated with this system-built type.

Arcal houses were built in a range of configurations, including two-storey detached, semi-detached and terraced dwellings. Roofs are of medium pitch with gable ends and are finished with interlocking concrete tiles laid over bituminous felt.

Front and rear elevations are generally rendered up to first floor level, with glazed asbestos cement sheet cladding above. Gable walls are typically rendered throughout. Detached houses often present a front-facing gable with a centrally positioned entrance, while terraced examples frequently include single-storey porch projections.

The most significant concern in early detached and semi-detached Arcal houses is corrosion to the bases of RSJ stanchions. This was evident during inspection of similar properties and can be severe where moisture has been present over long periods. In terraced houses, corrosion is more commonly superficial.

Rain penetration is frequently reported at panel-to-window junctions, with resulting internal water damage. Rot to plywood sheathing and timber studs, together with disintegration of plasterboard linings, is also a common issue and can affect both structural reliability and internal finishes.

Additional concerns include poorly constructed separating walls within roof spaces, roof leaks at chimney gutter flashings, missing or poorly fixed asbestos cement cladding, inadequate fire protection at first floor and eaves level, and cracking or spalling of external render.

Arcal houses require a clear understanding of non-traditional construction and a willingness to investigate concealed structural components. Particular attention should be paid to evidence of past water ingress, corrosion and material degradation.

• Confirm the condition of steel stanchions and protective coatings
• Assess the extent of timber decay and panel deterioration
• Identify the presence and condition of asbestos-containing materials

Arcal houses are not designated as defective under the Defective Premises Act. However, mortgage acceptance is influenced by condition, repair history and the quality of professional reporting. Clear evidence of maintenance and the absence of unresolved structural concerns are often decisive factors.

A building survey provides an informed assessment of the visible condition and construction of an Arcal house. Inspections are non-intrusive and limited to areas that are accessible at the time of inspection.

• Identify visible corrosion to steel stanchions and fixings
• Assess signs of dampness, moisture ingress, and condensation risk
• Comment on roof coverings, drainage details, and external envelope condition
• Review the general condition of accessible floors, ceilings, and structural elements
• Highlight defects that may require repair, monitoring, or further investigation

However, there are limitations to what a survey can determine without intrusive investigation.

• Confirm the condition of concealed steelwork within wall panels
• Assess hidden timber elements behind finishes or linings
• Determine the full extent of corrosion or decay within enclosed areas
• Inspect areas that are inaccessible or covered at the time of inspection

Where higher-risk indicators are identified, further specialist or intrusive investigation may be recommended.

For a thorough building survey in Greater London, an instant quotation can be obtained through the online survey calculator.