The British Iron and Steel Federation (BISF) Type A house is a notable example of post-war British architecture. These homes, constructed primarily in the mid-20th century, have unique characteristics and construction methods that set them apart from other property types. As an expert surveyor, I will delve into the intricate details of BISF Type A houses, providing a thorough understanding of their construction, typical hazards, and inspection tips. This guide aims to equip home buyers, investors, and fellow surveyors with the knowledge needed to make informed decisions regarding these properties.

Historical Context and Manufacturers

Origins and Purpose

The BISF Type A house emerged in response to the housing crisis following World War II. The British government sought to address the acute shortage of homes by promoting the use of non-traditional construction methods. The British Iron and Steel Federation, along with British Steel Homes Ltd, played a pivotal role in this initiative. These organizations aimed to utilize steel, a readily available material, to expedite the construction process and provide durable housing solutions.

Key Figures

Frederick Gibberd and Donovan Lee were the principal designers behind the BISF Type A house. Their innovative approach combined functionality with speed, resulting in a design that could be rapidly produced and assembled. The first BISF Type A houses were built in 1944, marking the beginning of a significant era in British housing history.

Production and Distribution

Approximately 36,000 BISF Type A houses were constructed across the UK. These homes were predominantly built in urban areas, where the demand for housing was most acute. The widespread distribution of these properties means that they can be found in various regions, each with its unique environmental and geographical challenges.

Identification Characteristics

Exterior Features

BISF Type A houses are easily recognizable by their distinct architectural features. These two-storey semi-detached houses typically have a shallow pitch gable roof covered with profiled steel sheets. The external walls are constructed with brick up to the first-floor level, with vertically profiled steel sheets above. Large ground floor windows and PS trims to windows and doors are also characteristic of these homes. The sloping eaves soffit adds to the unique aesthetic of the BISF Type A house.

Interior Layout

The interior layout of BISF Type A houses is designed for practicality and efficiency. The ground floor typically includes a spacious living area, kitchen, and utility spaces, while the first floor houses the bedrooms and bathroom. The use of steel framing allows for open-plan designs, providing flexibility in interior arrangements.

Construction Details

Substructure

The substructure of BISF Type A houses consists of concrete strip footings and brick under-building. A concrete slab, thickened around the perimeter, provides a stable foundation. A damp-proof course (DPC) is incorporated to prevent moisture ingress, ensuring the longevity of the structure.

Frame

The main frame of the BISF Type A house is constructed using a combination of rolled steel channels (RSC), rolled steel angles (RSA), and rolled steel joists (RSJ). The frame includes 17 RSC stanchions, 3 single-storey tubular steel stanchions, and various support beams and ties. The protective coating of red lead paint and black bituminous paint helps to prevent corrosion, a common issue with steel structures.

External Walls

The external walls are a combination of brick and block cavity walls up to the first-floor level, with vertically profiled steel sheets backed with fibreboard above. The steel sheets are hook-bolted to the cladding rails, providing a secure and weather-resistant exterior.

Partitions and Floors

Internal partitions are typically constructed using blockwork, providing robust and soundproof divisions between rooms. The ground floor is a concrete slab, while the first floor consists of concrete on expanded metal lathing. This construction method ensures a solid and durable flooring system.

Roof

The roof of the BISF Type A house is covered with profiled steel sheets backed with fibreboard. This combination provides both strength and insulation, protecting the interior from the elements.

Typical Hazards and Risks

Corrosion

One of the primary concerns with BISF Type A houses is the potential for corrosion of the steel frame. Despite the protective coatings, prolonged exposure to moisture can lead to rust and structural weakening. Regular inspections and maintenance are essential to mitigate this risk.

Thermal Insulation

The original design of BISF Type A houses did not prioritize thermal insulation. As a result, these homes can be less energy-efficient compared to modern properties. Retrofitting with additional insulation materials can help improve energy efficiency and reduce heating costs.

Asbestos

Asbestos was commonly used in construction during the mid-20th century, and BISF Type A houses are no exception. Asbestos-containing materials may be present in insulation, roofing, and other components. It is crucial to identify and manage asbestos hazards to ensure the safety of occupants.

Structural Movement

Over time, BISF Type A houses may experience structural movement due to ground conditions or the natural settling of the building. Cracks in walls and ceilings can indicate movement and should be investigated by a qualified surveyor.

Defective Premises Act

Classification

BISF Type A houses are not classified as defective under the Defective Premises Act. However, their non-traditional construction methods and potential hazards necessitate thorough inspections and maintenance to ensure they remain safe and habitable.

Legal Implications

While BISF Type A houses are not inherently defective, any issues arising from poor maintenance or neglect can lead to legal implications under the Defective Premises Act. Homeowners and landlords must ensure that these properties are kept in good condition to avoid potential liability.

Inspection Tips for Surveyors

Preliminary Assessment

Before conducting a detailed inspection, surveyors should familiarize themselves with the specific characteristics of BISF Type A houses. Reference materials such as “Steel framed and steel clad houses: inspection and assessment (BR 113)” and “Inspecting steel houses (IP 14/87)” provide valuable guidance.

External Inspection

During the external inspection, surveyors should pay close attention to the condition of the steel cladding and brickwork. Look for signs of corrosion, rust, and damage to the protective coatings. Inspect the roof for any missing or damaged steel sheets and check the condition of the eaves soffit.

Internal Inspection

Inside the property, surveyors should examine the steel frame for signs of corrosion or structural movement. Check for cracks in walls and ceilings, which may indicate underlying issues. Inspect the flooring for any signs of dampness or deterioration, particularly in the concrete slab.

Asbestos Management

Given the potential presence of asbestos, surveyors should identify any suspect materials and recommend appropriate testing and management. Asbestos-containing materials should be handled by licensed professionals to ensure safety.

Thermal Performance

Assess the thermal performance of the property by checking for adequate insulation and identifying areas where improvements can be made. Retrofitting with modern insulation materials can significantly enhance energy efficiency.

Typical Defects in BISF Type A Houses

Corrosion of Steel Frame

As previously mentioned, corrosion of the steel frame is a common issue in BISF Type A houses. Regular inspections and maintenance are crucial to prevent rust and structural weakening. Applying protective coatings and addressing any moisture ingress can help mitigate this risk.

Cracking in Walls and Ceilings

Cracks in walls and ceilings can indicate structural movement or settlement. These cracks should be investigated to determine the underlying cause and appropriate remedial action. In some cases, structural reinforcement may be necessary to ensure stability.

Dampness and Moisture Ingress

Dampness and moisture ingress can lead to a range of issues, including mould growth, deterioration of materials, and corrosion of the steel frame. Surveyors should check for signs of dampness, particularly in the ground floor slab and around windows and doors. Addressing any sources of moisture and improving ventilation can help prevent these problems.

Poor Thermal Insulation

The original design of BISF Type A houses did not prioritize thermal insulation, resulting in potential energy efficiency issues. Retrofitting with modern insulation materials can help improve thermal performance and reduce heating costs. Surveyors should assess the current insulation levels and recommend appropriate upgrades.

Asbestos-Containing Materials

Asbestos-containing materials may be present in various components of BISF Type A houses. Identifying and managing these materials is crucial to ensure the safety of occupants. Surveyors should recommend appropriate testing and, if necessary, removal or encapsulation by licensed professionals.

Maintenance and Improvement Tips

Regular Inspections

Regular inspections are essential to identify and address any issues in BISF Type A houses. Homeowners and landlords should schedule routine inspections by qualified surveyors to ensure the property remains in good condition.

Protective Coatings

Applying protective coatings to the steel frame and cladding can help prevent corrosion and extend the lifespan of the property. Regular maintenance of these coatings is crucial to ensure their effectiveness.

Insulation Upgrades

Improving the thermal insulation of BISF Type A houses can enhance energy efficiency and reduce heating costs. Retrofitting with modern insulation materials, such as cavity wall insulation and loft insulation, can significantly improve thermal performance.

Asbestos Management

Proper management of asbestos-containing materials is essential to ensure the safety of occupants. Surveyors should identify any suspect materials and recommend appropriate testing and management. Asbestos-containing materials should be handled by licensed professionals to ensure safety.

Structural Reinforcement

In cases where structural movement or settlement is identified, appropriate remedial action should be taken to ensure stability. This may include structural reinforcement or underpinning to address any underlying issues.

Conclusion

BISF Type A houses are a unique and significant part of British housing history. Their distinctive construction methods and materials present both opportunities and challenges for homeowners, investors, and surveyors. By understanding the key characteristics, typical hazards, and maintenance requirements of these properties, stakeholders can make informed decisions and ensure the longevity and safety of BISF Type A houses.

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.