Overview
The British Iron & Steel Federation (BISF) Type B house is a product of post-war reconstruction, developed to address the acute housing shortage following the Second World War. These properties were constructed using system-built methods and steel framing, creating a distinctive form of non-traditional housing that remains in use today.
BISF Type B houses were developed by the British Iron & Steel Federation and British Steel Homes Ltd, with architectural input from designers including Frederick Gibberd and Donovan Lee. Construction began in 1944, with approximately 2,000 units built across the UK.
Typical characteristics & construction
BISF Type B houses are two-storey, semi-detached dwellings constructed around a steel frame. The system was designed for speed of construction while maintaining structural robustness through standardised steel components.
External walls are formed using rendered grooved steel sheets up to first-floor level, with shiplap steel sheets above. Gable walls incorporate a cavity with a timber frame lined internally with fibreboard and plasterboard.
Roofs are shallow pitched and covered with profiled steel sheets backed with fibreboard. Windows are typically wide at both ground and first-floor levels, with pressed steel trims to openings and a sloping eaves soffit.
| Element | Typical construction | Inspection focus |
|---|---|---|
| Substructure | Concrete strip footings with brick under-building and perimeter thickened slab | Cracking, settlement, DPC continuity |
| Frame | Steel stanchions, perimeter ties, joists, and roof trusses | Corrosion, protective coating condition |
| External walls | Rendered and shiplap steel sheets, timber-framed gables | Corrosion, cracking, moisture ingress |
| Floors | Concrete ground floor, timber first floor with T&G boarding | Movement, dampness, deflection |
| Roof | Profiled steel sheets with fibreboard backing | Corrosion, fixings, weather-tightness |
Potential hazards & inspection priorities
The primary concern with BISF Type B houses is corrosion of the steel frame, particularly where moisture has been allowed to persist. Protective coatings deteriorate over time, increasing the risk of section loss if maintenance has been limited.
Thermal performance is modest by modern standards, and condensation can be an issue where insulation upgrades and ventilation have not been addressed. Asbestos-containing materials may also be present in elements such as linings and insulation.
Is this house right for you?
A BISF Type B house may be suitable for purchasers who understand non-traditional steel-framed construction and are prepared to base decisions on condition rather than age alone.
- Obtain a full building survey from a surveyor experienced with steel-framed housing
- Review evidence of corrosion protection and past maintenance
- Consider the implications of insulation upgrades and ongoing management
Mortgage & resale considerations
Mortgage acceptance for BISF Type B houses varies between lenders and is influenced by condition, maintenance history, and the clarity of professional reporting. Clear evidence of inspection and repair can be influential.
Resale prospects are generally stronger where corrosion risks have been addressed and documented.
What a survey can — and cannot — tell you
A building survey provides an informed assessment of the visible condition and construction of a BISF Type B house. Inspections are non-intrusive and limited to areas that are accessible at the time of inspection.
- Identify visible corrosion to steel framing and wall panels
- 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 steel elements within walls and floors
- Assess hidden structural connections behind finishes
- Determine the full extent of internal corrosion where components are enclosed
- 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.
Considering a BISF Type B house?
A detailed building survey can help clarify construction-specific risks before committing to a purchase.
Get your instant survey quoteDisclaimer: This article is provided for general educational purposes only and is based on industry research, professional knowledge, and experience. It does not relate to any specific property and should not be relied upon when making a purchasing decision. Prospective purchasers should always commission an independent RICS-qualified surveyor to conduct a full inspection and provide a report on the actual condition of any property of interest.
