Overview of the B-J House

The B-J house, a notable example of post-war British architecture, stands as a testament to the ingenuity and resourcefulness of the era. Manufactured by B & J Structures Ltd and designed by J Markham, these properties were constructed in 1946, a period marked by a significant housing shortage following World War II. The B-J house is a 2-storey semi-detached property, characterized by its unique construction materials and methods, which were innovative at the time but now present certain challenges for modern homeowners and investors.

Typical Locations and Numbers Built

While exact numbers of B-J houses built are not readily available, these properties are typically found in suburban areas across the UK. They were part of a broader effort to quickly and efficiently provide housing for the growing population in the post-war period. The use of prefabricated materials and system-built techniques allowed for rapid construction, making these homes a common sight in many British towns and cities.

Manufacturers and Designers

B & J Structures Ltd, the manufacturers of the B-J house, were pioneers in the use of prefabricated materials. Their collaboration with designer J Markham resulted in a property that was both functional and economical. The design focused on utilizing readily available materials, such as asbestos cement sheets and steel frames, to create a durable and cost-effective housing solution.

Identification Characteristics

Identifying a B-J house involves looking for several distinctive features:

• 2-storey semi-detached structure: These houses are typically semi-detached, meaning they share a common wall with an adjacent property.
• Shallow pitch gable roof: The roof is covered with profiled asbestos cement sheets, a common material used in the post-war period.
• External walls: The walls are made of exposed eaves height RSA framed panels infilled with fluted asbestos cement sheets. The gable apex is also clad with profiled asbestos cement sheets.
• PC canopy over front door: A pre-cast concrete canopy is often found over the front door, adding to the distinctive look of the property.

Typical Characteristics and Hazards

Construction Details

The construction of B-J houses involves several key components:

• Substructure: Concrete pad below stanchions and a concrete oversite slab with a damp-proof course (DPC).
• Frame: The frame consists of double RSC stanchions forming an I-section, RSA lattice spandrel beams, RSA lattice floor support beams, RSC floor support beams, flitched floor joists, RSJ eaves beams, RSC hangers, RSA lattice ridge beam, and RSA roof trusses and purlins.
• External Walls: Eaves height RSA framed panels infilled with fluted asbestos cement sheets backed with sprayed asbestos, cavity, timber framing infilled with woodwool, and lined with plywood.
• Gable Apex: Clad with profiled asbestos cement sheets.
• Separating Wall: Concrete block cavity wall to the first floor level and solid wall above, faced with timber framing lined with plywood throughout.
• Partitions: Timber stud infilled with woodwool and lined with plywood.
• Ground Floor: Concrete.
• First Floor: Tongue and groove (T&G) boarding on timber battens.
• Ceilings: Plasterboard.
• Roof: Profiled asbestos cement sheets.

Typical Hazards and Risks

While the B-J house was innovative for its time, several hazards and risks are associated with this type of property:

• Asbestos: The use of asbestos cement sheets in the roof and walls poses a significant health risk if disturbed. Asbestos fibers can cause serious respiratory diseases, including asbestosis and mesothelioma.
• Structural Integrity: The steel frame, if not properly maintained, can suffer from corrosion, leading to structural weaknesses.
• Thermal Insulation: The original construction materials, such as woodwool and asbestos, provide poor thermal insulation by modern standards, leading to higher energy costs.
• Damp and Condensation: The concrete substructure and lack of modern damp-proofing measures can result in damp and condensation issues, which can further compromise the structural integrity and indoor air quality.

Defective Premises Act

The B-J house is not specifically classed as defective under the Defective Premises Act. However, the presence of asbestos and potential structural issues mean that buyers should exercise caution and seek a thorough survey before purchasing. The Defective Premises Act requires that properties be fit for habitation, and any significant defects that compromise this standard could potentially fall under its purview.

Inspection Guide for Surveyors

When inspecting a B-J house, surveyors should follow a systematic approach to identify potential issues and assess the overall condition of the property. Here are some key areas to focus on:

External Inspection

• Roof: Check for any damage or deterioration in the asbestos cement sheets. Look for signs of moss or lichen growth, which can indicate moisture retention.
• Walls: Inspect the fluted asbestos cement sheets for cracks or damage. Pay particular attention to the gable apex and the condition of the profiled asbestos cement sheets.
• Canopy: Examine the pre-cast concrete canopy over the front door for any signs of cracking or spalling.

Internal Inspection

• Frame: Assess the condition of the steel frame, looking for signs of corrosion or rust. Pay attention to the protective coating and any areas where the metal is exposed.
• Walls and Partitions: Check for any signs of damp or condensation. Inspect the timber framing and woodwool infill for signs of rot or deterioration.
• Floors: Examine the concrete ground floor for any cracks or unevenness. Check the first floor T&G boarding for any signs of warping or damage.
• Ceilings: Look for any cracks or sagging in the plasterboard ceilings, which could indicate structural issues or water damage.

Asbestos Management

Given the extensive use of asbestos in B-J houses, it is crucial to manage this material safely:

• Identification: Confirm the presence of asbestos in the roof, walls, and any other areas where it may have been used.
• Condition Assessment: Determine the condition of the asbestos-containing materials. If they are in good condition and undisturbed, they may not pose an immediate risk. However, damaged or deteriorating asbestos should be addressed promptly.
• Professional Removal: If asbestos removal is necessary, it should be carried out by licensed professionals following strict safety protocols.

Typical Construction Elements

Roof

The roof of a B-J house is characterized by its shallow pitch and the use of profiled asbestos cement sheets. These sheets were chosen for their durability and fire-resistant properties. However, over time, they can become brittle and prone to cracking, especially if subjected to physical impact or extreme weather conditions.

Walls

The external walls are constructed using RSA framed panels infilled with fluted asbestos cement sheets. These panels are backed with sprayed asbestos, creating a cavity that is further infilled with woodwool and lined with plywood. This multi-layered construction provides some degree of thermal insulation but falls short of modern standards.

Floors

The ground floor is made of concrete, providing a solid and durable base. The first floor consists of tongue and groove (T&G) boarding on timber battens, which offers a stable and level surface for flooring materials.

Main Frame

The main frame of the B-J house is constructed using a combination of RSC stanchions, RSA lattice beams, and RSJ eaves beams. This steel framework provides the structural support for the entire building. However, the steel components must be protected from corrosion to maintain their integrity.

Typical Defects

Asbestos-Related Issues

As previously mentioned, the extensive use of asbestos in the construction of B-J houses poses significant health risks. Over time, asbestos-containing materials can deteriorate, releasing harmful fibers into the air. It is essential to manage and, if necessary, remove these materials safely.

Corrosion of Steel Frame

The steel frame, while providing robust structural support, is susceptible to corrosion if not adequately protected. Corrosion can weaken the frame, leading to structural instability. Regular inspections and maintenance are crucial to prevent this issue.

Damp and Condensation

The concrete substructure and lack of modern damp-proofing measures can result in damp and condensation issues. These problems can lead to mold growth, wood rot, and further structural damage if not addressed promptly.

Poor Thermal Insulation

The original construction materials, such as woodwool and asbestos, provide inadequate thermal insulation by modern standards. This can result in higher energy costs and reduced comfort for occupants. Upgrading the insulation can significantly improve the energy efficiency of the property.

Maintenance and Improvement Tips

Asbestos Management

• Regular Inspections: Conduct regular inspections to monitor the condition of asbestos-containing materials. Look for any signs of damage or deterioration.
• Professional Removal: If asbestos removal is necessary, hire licensed professionals to carry out the work safely and in compliance with regulations.
• Encapsulation: In some cases, encapsulating asbestos-containing materials can be a safer and more cost-effective solution than removal.

Corrosion Prevention

• Protective Coatings: Apply protective coatings to exposed steel components to prevent corrosion. Regularly inspect and maintain these coatings to ensure their effectiveness.
• Moisture Control: Address any sources of moisture that could contribute to corrosion, such as leaks or condensation. Ensure proper ventilation to reduce humidity levels.

Damp and Condensation Control

• Damp-Proofing: Install modern damp-proofing measures, such as a damp-proof course (DPC) and damp-proof membrane (DPM), to prevent moisture ingress.
• Ventilation: Improve ventilation in the property to reduce condensation. Consider installing extractor fans in areas prone to moisture, such as kitchens and bathrooms.
• Dehumidifiers: Use dehumidifiers to control humidity levels and prevent condensation.

Insulation Upgrades

• Wall Insulation: Upgrade the insulation in the external walls to improve thermal performance. Consider using modern insulation materials that provide better energy efficiency.
• Roof Insulation: Insulate the roof space to reduce heat loss and improve energy efficiency. Ensure that the insulation is properly installed and does not obstruct ventilation.
• Floor Insulation: Insulate the ground floor to reduce heat loss and improve comfort. Consider using insulation boards or underfloor heating systems.

Conclusion

The B-J house, with its unique construction and historical significance, presents both opportunities and challenges for modern home buyers and investors. Understanding the typical characteristics, hazards, and maintenance requirements of these properties is essential for making informed decisions. By conducting thorough inspections and addressing any issues promptly, you can ensure that a B-J house remains a safe and comfortable home for years to come.

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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