The British Iron & Steel Federation (BISF) Type B house stands as a testament to post-war ingenuity and the drive to provide affordable housing in the UK. These properties, constructed primarily in the mid-20th century, have unique characteristics and considerations that potential buyers and investors should be aware of. This article delves into the history, construction, typical defects, and inspection tips for BISF Type B houses, offering a thorough understanding for those interested in these distinctive homes.

Historical Context and Manufacturers

The BISF Type B house emerged in response to the urgent need for housing following World War II. The British government, facing a severe housing shortage, turned to innovative construction methods to quickly and efficiently build homes. The British Iron & Steel Federation, along with British Steel Homes Ltd, spearheaded the development of these properties. Notable designers such as Frederick Gibberd and Donovan Lee played pivotal roles in the architectural and structural design of these houses.

Period of Construction

The BISF Type B houses were primarily constructed starting in 1944. This period marked a significant shift towards system-built properties, leveraging steel as a primary material to expedite the building process. Approximately 2,000 of these homes were built, predominantly in urban and suburban areas across the UK.

Typical Locations

BISF Type B houses can be found in various regions throughout the UK, with a higher concentration in areas that experienced significant bomb damage during the war. Cities like London, Birmingham, and Manchester have notable clusters of these properties, reflecting the post-war reconstruction efforts.

Identification Characteristics

Recognizing a BISF Type B house involves noting several distinctive features. These two-storey semi-detached houses exhibit a shallow pitch gable roof covered with profiled steel sheets. The external walls are rendered up to the first-floor level, with shiplap steel sheets above. Wide ground and first-floor windows dominate the front elevation, framed by PS trims to windows, mullions, and doors. The sloping eaves soffit further distinguishes these homes.

Reference and Documentation

For those seeking detailed technical guidance, the PWBS No. 23 document provides comprehensive information. Additionally, the Building Research Establishment (BRE) offers valuable resources, including “Steel framed and steel clad houses: inspection and assessment (BR 113),” “Inspecting steel houses (IP 14/87),” and “Maintaining and improving steel houses (IP 15/87).”

Construction Details

Understanding the construction of BISF Type B houses is crucial for assessing their condition and potential issues. These homes feature a robust steel frame, concrete substructure, and distinctive wall and roof materials.

Substructure

The substructure consists of concrete strip footings and brick under-building, with a concrete slab thickened around the perimeter. A damp-proof course (DPC) is also present to prevent moisture ingress.

Frame

The frame is composed of 19 PSC stanchions, three single-storey tubular stanchions, and one double PSC forming an I-section floor support beam. Additional components include PSC perimeter ties, floor joists, ceiling joists, and roof trusses and purlins. The steel elements are protected with a metallic phosphate primer and black bituminous paint, while the steel sheets are galvanized and coated with red lead paint.

External Walls

The front and rear walls are constructed from rendered grooved steel sheets up to the first-floor level, with shiplap steel sheets above. The gable walls follow a similar pattern, with a cavity and timber frame lined with fibreboard and plasterboard.

Separating Wall

A block cavity wall serves as the separating wall, with a single leaf block in the roof space.

Partitions

Internal partitions are typically constructed from block materials.

Floors

The ground floor is made of concrete, while the first floor features tongue-and-groove boarding on timber battens.

Ceilings

Ceilings are generally plasterboard, providing a smooth finish.

Roof

The roof is covered with profiled steel sheets backed with fibreboard, offering durability and weather resistance.

Typical Defects and Hazards

While BISF Type B houses were innovative for their time, they are not without their challenges. Potential buyers and investors should be aware of common defects and hazards associated with these properties.

Corrosion

One of the primary concerns with BISF Type B houses is corrosion of the steel frame. Over time, exposure to moisture can lead to rust and structural weakening. Regular inspections and maintenance are essential to mitigate this risk.

Insulation and Thermal Performance

The original construction of BISF Type B houses did not prioritize thermal insulation. As a result, these homes can suffer from poor energy efficiency, leading to higher heating costs. Retrofitting insulation can significantly improve thermal performance.

Asbestos

Asbestos was commonly used in construction materials during the mid-20th century. BISF Type B houses may contain asbestos in insulation, ceiling tiles, and other components. Professional asbestos surveys and removal are crucial for ensuring safety.

Damp and Condensation

Due to the steel frame and concrete substructure, BISF Type B houses can be prone to damp and condensation issues. Proper ventilation and damp-proofing measures are necessary to prevent moisture-related problems.

Structural Movement

Over time, structural movement can occur, leading to cracks in walls and ceilings. Regular monitoring and addressing any signs of movement promptly can help maintain the integrity of the property.

Inspection Tips for BISF Type B Houses

Conducting a thorough inspection of a BISF Type B house requires attention to specific areas and potential issues. Here are some key tips for inspecting these properties:

Exterior Inspection

1. Roof: Check for signs of corrosion or damage to the profiled steel sheets. Ensure that the roof is properly sealed and free from leaks.
2. Walls: Inspect the rendered and shiplap steel sheets for any signs of rust, damage, or deterioration. Pay attention to the condition of the PS cover strips and trims.
3. Windows and Doors: Examine the wide ground and first-floor windows for any signs of wear, damage, or poor sealing. Ensure that the PS trims are intact and in good condition.
4. Eaves and Soffits: Check the sloping eaves soffit for any signs of damage or decay. Ensure that the eaves are properly ventilated to prevent moisture buildup.

Interior Inspection

1. Frame: Inspect the steel frame for any signs of corrosion or structural weakening. Pay particular attention to areas where moisture may have penetrated.
2. Walls and Partitions: Check for cracks, damp patches, or signs of structural movement. Ensure that the block partitions are in good condition.
3. Floors: Examine the concrete ground floor and timber first floor for any signs of damage, wear, or movement. Ensure that the tongue-and-groove boarding is secure.
4. Ceilings: Inspect the plasterboard ceilings for any signs of cracks, damp, or damage. Ensure that the ceilings are properly insulated and ventilated.

Additional Considerations

1. Insulation: Assess the thermal performance of the property and consider retrofitting insulation to improve energy efficiency.
2. Asbestos: Conduct a professional asbestos survey to identify and safely remove any asbestos-containing materials.
3. Damp and Condensation: Ensure that the property is properly ventilated and damp-proofed to prevent moisture-related issues.
4. Structural Movement: Monitor for any signs of structural movement and address any issues promptly to maintain the integrity of the property.

Defective Premises Act and BISF Type B Houses

The Defective Premises Act 1972 imposes a duty on builders, developers, and landlords to ensure that properties are constructed and maintained to a reasonable standard. While BISF Type B houses were innovative for their time, they may not meet modern building standards. Potential buyers and investors should be aware of their responsibilities under the Act and take steps to address any defects or hazards.

Legal Considerations

1. Duty of Care: Builders and developers have a duty of care to ensure that properties are constructed to a reasonable standard. This includes addressing any defects or hazards that may pose a risk to occupants.
2. Maintenance: Landlords and property owners have a responsibility to maintain properties in a safe and habitable condition. Regular inspections and maintenance are essential to meet this obligation.
3. Remediation: If defects or hazards are identified, property owners must take steps to remediate the issues promptly. This may involve repairs, retrofitting, or other measures to ensure the safety and integrity of the property.

Conclusion

BISF Type B houses represent a unique chapter in the history of UK housing, reflecting the post-war drive for affordable and efficient construction. While these properties have their challenges, they also offer opportunities for buyers and investors willing to invest in maintenance and improvements. Understanding the history, construction, typical defects, and inspection tips for BISF Type B houses is crucial for making informed decisions and ensuring the long-term safety and value of these homes.

At Flettons, we’re committed to safeguarding your investment. When considering a property purchase, trust our seasoned expertise to reveal any hidden threats. For a thorough building survey, get your instant quote through our quote calculator or reach out directly at 0203 691 0451. Your home’s safety is our top priority.

---