Understanding the Arcal House

The Arcal house, a distinctive type of system-built property, emerged during the 1960s in the UK. Designed and manufactured by Gee Walker & Slater, these homes were part of a broader movement towards prefabricated housing solutions. With only 100 units constructed, Arcal houses are relatively rare, making them a unique find for home buyers and investors. Typically found as bungalows or two-storey semi-detached and terraced houses, these properties are characterized by their medium pitch gable roofs covered with interlocking concrete tiles, rendered external walls, and flat roof front lobbies. Metal window frames are another hallmark of the Arcal design.

Historical Context and Manufacturing Details

The 1960s was a period marked by a housing boom in the UK, driven by the need for rapid construction to address post-war housing shortages. System-built homes like the Arcal were developed to meet this demand efficiently. Gee Walker & Slater, the manufacturers, were known for their innovative approach to construction, utilizing prefabrication techniques to expedite the building process. The Arcal house was designed to be both cost-effective and quick to assemble, making it an attractive option for local councils and developers at the time.

Construction Characteristics

The construction of Arcal houses is a testament to the ingenuity of mid-20th-century building practices. The substructure consists of concrete footings and a brick underbuilding, supporting a concrete slab with a damp-proof course (DPC). The external walls are built using a platform frame construction method, featuring storey-height timber frame panels. These panels are sheathed externally with plywood, overlaid with bituminous paper, and directly clad with render on expanded metal mesh. Internally, the walls are lined with foil-backed plasterboard, providing a degree of insulation and moisture resistance.

The separating walls between units are constructed as 11-inch block cavity walls, offering sound and thermal insulation. Internal partitions are made from timber studs lined with plasterboard. The ground floor is typically a concrete slab, while the first floor consists of tongue-and-groove (T&G) boarding on timber joists. Ceilings are finished with plasterboard, and the roof structure comprises timber trusses covered with bituminous felt and interlocking concrete tiles.

Typical Hazards and Risks

While Arcal houses were innovative for their time, they are not without their challenges. One of the primary concerns is the localised decay of timber sheathing and frame, which can compromise the structural integrity of the property. Additionally, the corrosion of metal trim strips and the foil-backing to plasterboard linings are common issues that can lead to further deterioration if not addressed promptly.

These properties are not classified as defective under the Defective Premises Act, but potential buyers should be aware of the inherent risks associated with their construction. Regular maintenance and thorough inspections are crucial to preserving the condition of an Arcal house.

Inspection Tips for Surveyors

When inspecting an Arcal house, surveyors should pay close attention to several key areas. Start by examining the external render for signs of cracking or detachment, which could indicate underlying issues with the timber frame or sheathing. Check the condition of the metal window frames for corrosion, as this can lead to water ingress and further damage.

Inspect the roof for any missing or damaged tiles, and assess the condition of the bituminous felt beneath. Inside, look for signs of moisture damage or mould on the plasterboard linings, particularly around windows and in areas with poor ventilation. The foil-backing on the plasterboard should also be checked for corrosion, as this can affect the thermal performance of the property.

Common Defects and Maintenance Strategies

Arcal houses, like many system-built homes from the 1960s, are prone to certain defects that require regular attention. The most common issues include timber decay, metal corrosion, and moisture ingress. To mitigate these risks, homeowners should implement a proactive maintenance strategy.

Regularly inspect and repair any damage to the external render to prevent water penetration. Ensure that gutters and downpipes are clear and functioning properly to direct rainwater away from the building. Address any signs of timber decay promptly by replacing affected sections and treating the surrounding area with a preservative.

For metal components, such as window frames and trim strips, apply a rust-inhibiting primer and paint to protect against corrosion. If the foil-backing on plasterboard linings shows signs of deterioration, consider replacing the affected panels to maintain the property’s insulation and moisture resistance.

Investment Potential and Market Considerations

Despite their challenges, Arcal houses can offer significant investment potential, particularly for those willing to undertake necessary repairs and upgrades. Their unique construction and historical significance can make them attractive to niche buyers seeking character properties with a story.

When considering an Arcal house as an investment, it’s essential to conduct a thorough cost-benefit analysis. Factor in the costs of repairs and ongoing maintenance against the potential rental income or resale value. Additionally, consider the location of the property, as this can significantly impact its marketability and long-term appreciation.

Modern Upgrades and Renovation Opportunities

For those looking to modernize an Arcal house, there are several renovation opportunities that can enhance both its functionality and aesthetic appeal. Upgrading the insulation and heating systems can improve energy efficiency, reducing utility costs and increasing comfort for occupants.

Consider replacing single-glazed metal windows with double-glazed units to enhance thermal performance and reduce noise. Modern render systems can be applied to the exterior to improve weather resistance and update the property’s appearance.

Internally, open-plan layouts can be achieved by removing non-load-bearing partitions, creating a more spacious and contemporary living environment. Updating kitchens and bathrooms with modern fixtures and finishes can also add significant value to the property.

Navigating Legal and Regulatory Considerations

When purchasing an Arcal house, it’s important to be aware of any legal and regulatory considerations that may apply. While these properties are not classified as defective under the Defective Premises Act, they may still be subject to specific building regulations and planning permissions, particularly if significant alterations or extensions are planned.

Consult with a qualified surveyor or legal professional to ensure compliance with all relevant regulations and to address any potential issues that may arise during the purchase process. This due diligence can help prevent costly delays and complications down the line.

Conclusion

Arcal houses represent a unique chapter in the history of UK housing, offering both challenges and opportunities for home buyers and investors. By understanding their construction characteristics, potential hazards, and maintenance requirements, you can make informed decisions about purchasing and renovating these distinctive properties.

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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