Historical Context and Manufacturing Details

The Buchan house, a distinctive type of system-built property, holds a unique place in the history of British housing. Manufactured by Johnston Bros. Ltd and designed by a team of innovative architects, these homes were constructed during the immediate post-war period, specifically between 1945 and 1946. Only five of these properties were built, making them a rare find in today’s property market.

These homes were primarily located in rural and suburban areas, where the need for quick and efficient housing solutions was paramount. The Buchan house is also known by alternative names, but its most recognizable feature is its L-shaped plan, which sets it apart from other post-war constructions.

Identifying Characteristics

Architectural Features

The Buchan house is a detached bungalow with a medium pitch hipped roof covered with plain clay tiles. The external walls are either paint harled or plain painted steel sheets, giving the property a distinctive appearance. One of the most notable features is the front door, located in the internal corner of the ‘L’ shape, with an extended roof forming a porch. Additionally, the front elevation windows are designed to return around the corner, adding to the unique aesthetic of the property.

Structural Components

The substructure of the Buchan house consists of concrete strip footings and under-building, with a concrete upstand and a damp-proof course (DPC). The main frame is constructed using 56 RSA stanchions, 2 RSJ floor support beams, 6 RSA perimeter beams, and RSA roof trusses, purlins, and hip rafters. The protective coating for these components includes bitumen and oil paint, ensuring durability and resistance to the elements.

The external walls are made of paint harled flat steel sheets, supported by timber framing lined with plasterboard. Mineral wool insulation is placed between the frame studs to provide thermal efficiency. Internal partitions are constructed using timber stud lined with plasterboard, and the ground floor features tongue and groove (T&G) boarding on timber joists. The ceilings are also lined with plasterboard, while the roof comprises timber purlins, timber boarding, bituminous felt, and single lap tiles.

Typical Hazards and Risks

Structural Integrity

One of the primary concerns with Buchan houses is the potential for structural degradation over time. The steel frame, while robust, can be susceptible to corrosion if not properly maintained. This is particularly true in areas with high humidity or exposure to saltwater, which can accelerate the rusting process.

Insulation and Energy Efficiency

While the mineral wool insulation provides some thermal efficiency, it may not meet modern standards. Homeowners may find that these properties are less energy-efficient compared to newer builds, leading to higher heating costs. Upgrading the insulation can be a costly but necessary investment to improve the property’s energy performance.

Damp and Moisture

The concrete upstand and DPC are designed to prevent moisture ingress, but over time, these components can deteriorate. If the DPC fails, it can lead to rising damp, which can cause significant damage to the internal plasterboard and timber framing. Regular inspections and maintenance are crucial to mitigate this risk.

Asbestos

Given the period during which these houses were built, there is a possibility that asbestos-containing materials were used in the construction. Asbestos was commonly used for its fire-resistant properties, but it poses serious health risks if disturbed. A thorough survey should be conducted to identify and safely remove any asbestos materials.

Defective Premises Act Considerations

The Buchan house is not classed as defective under the Defective Premises Act. However, this does not mean that the property is free from issues. Potential buyers should be aware of the typical defects associated with this type of construction and take appropriate measures to address them.

Inspection Guidelines for Surveyors

Preliminary Assessment

Before conducting a detailed inspection, surveyors should familiarize themselves with the specific characteristics of the Buchan house. Reference materials such as “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)” provide valuable guidance on the inspection and assessment of steel-framed houses.

External Inspection

1. Roof: Inspect the clay tiles for any signs of damage or displacement. Check the bituminous felt for wear and tear, and ensure that the timber purlins and boarding are in good condition.
2. Walls: Examine the paint harled or plain painted steel sheets for corrosion, peeling paint, or other signs of deterioration. Pay particular attention to the areas around windows and doors, where moisture ingress is more likely.
3. Foundation: Assess the concrete strip footings and upstand for cracks or other signs of structural movement. Ensure that the DPC is intact and functioning correctly.

Internal Inspection

1. Frame: Check the RSA stanchions, RSJ floor support beams, and RSA perimeter beams for any signs of rust or corrosion. Ensure that the protective coating is still effective.
2. Insulation: Inspect the mineral wool insulation for any signs of dampness or degradation. Consider upgrading the insulation to improve energy efficiency.
3. Partitions and Ceilings: Examine the plasterboard for cracks, damp patches, or other signs of damage. Ensure that the timber stud framing is in good condition.
4. Flooring: Check the T&G boarding and timber joists for any signs of rot or insect infestation. Ensure that the flooring is level and stable.

Specialist Surveys

Given the potential presence of asbestos, a specialist asbestos survey should be conducted. Additionally, a damp survey may be necessary to identify any issues with rising damp or moisture ingress.

Typical Defects and Maintenance Tips

Corrosion of Steel Frame

Corrosion is one of the most common issues with Buchan houses. Regular inspections and maintenance of the protective coating can help prevent rust. If corrosion is detected, it should be treated promptly to prevent further damage.

Insulation Upgrades

Upgrading the mineral wool insulation can significantly improve the property’s energy efficiency. Consider installing modern insulation materials that meet current building standards.

Damp Proofing

Ensure that the DPC is functioning correctly and consider installing additional damp-proofing measures if necessary. Regularly inspect the concrete upstand and footings for any signs of moisture ingress.

Asbestos Management

If asbestos-containing materials are identified, they should be managed or removed by a licensed professional. Do not attempt to remove asbestos yourself, as this can release harmful fibres into the air.

Conclusion

The Buchan house, with its unique architectural features and historical significance, offers a distinctive option for home buyers and investors. However, it is essential to be aware of the typical hazards and risks associated with this type of property. Regular inspections and maintenance are crucial to ensure the structural integrity and safety of the home.

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.

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