Understanding the Swiftplan Multiflex H12

The Swiftplan Multiflex H12, a distinctive property type, emerged during the mid-1960s, a period marked by innovative construction techniques and a pressing need for affordable housing solutions in the UK. Manufactured by Swiftplan Ltd and designed by E S Erkan, these homes were constructed between 1966 and 1968. With only 100 units built, they are a rare find in today’s property market. Known alternatively as Multiflex, Swiftplan, or Swiftplan H12, these properties are typically located in suburban areas, offering a unique blend of architectural style and historical significance.

Key Characteristics of the Swiftplan Multiflex H12

The Swiftplan Multiflex H12 properties are primarily bungalows and two-storey semi-detached or terraced houses. They are easily identifiable by their shallow pitch gable roofs, which are covered with concrete tiles, or alternatively, flat roofs with bituminous felt. The external walls feature a distinctive design, with render extending to the ground floor window head level and horizontally profiled steel weatherboarding above. This combination of materials not only provides a unique aesthetic but also serves functional purposes in terms of weather resistance and insulation.

Construction Details

The construction of the Swiftplan Multiflex H12 is a testament to the innovative building techniques of its time. Here’s a detailed breakdown of its construction elements:

• Substructure: The foundation consists of concrete strip footings and concrete under-building, providing a solid base for the structure. A damp-proof course (DPC) is included to prevent moisture ingress.

• External Walls: These are constructed using a platform frame method, with storey-height timber frame panels based on a 2-foot module. The panels are sheathed externally with plywood and directly clad with render up to the first-floor level, with horizontally profiled steel weatherboarding above. The walls are lined with plasterboard backed by a polyethylene vapour control layer, and mineral fibre insulation is placed between the frame studs.

• Separating Walls: These feature a timber frame cavity backed with plywood and lined with three layers of plasterboard, with mineral fibre insulation in the cavity for sound and thermal insulation.

• Partitions: Internal partitions are made of timber stud lined with plasterboard.

• Floors: The ground floor is concrete with rigid foam plastics insulation at the perimeter, while the first floor consists of plywood on timber joists.

• Ceilings: Ceilings are made of plasterboard, with foil-backed plasterboard used in the roof space for additional insulation.

• Roof: The roof structure comprises timber trusses, bituminous felt, and concrete tiles, with mineral fibre insulation at ceiling level.

Variants and Alternatives

Some variants of the Swiftplan Multiflex H12 feature flat roofs made of plywood decking, softboard insulation, and bituminous felt. Additionally, certain models have external wall timber frame panels sheathed externally with fibreboard, and honeycomb plasterboard partition linings.

Typical Hazards and Risks

While the Swiftplan Multiflex H12 offers unique architectural features, potential buyers should be aware of certain hazards and risks associated with this property type:

• Timber Frame Deterioration: Over time, timber frames can be susceptible to rot and insect infestation, particularly if moisture ingress occurs. Regular inspections and maintenance are crucial to prevent structural issues.

• Roofing Concerns: The flat roof variants may experience water pooling and leakage if not properly maintained. Ensuring adequate drainage and regular roof inspections can mitigate these risks.

• Insulation and Energy Efficiency: While the original mineral fibre insulation provides some thermal resistance, upgrading to modern insulation materials can significantly improve energy efficiency and reduce heating costs.

• Render and Weatherboarding Maintenance: The external render and steel weatherboarding require periodic maintenance to prevent cracking and corrosion, which can compromise the building’s weather resistance.

Defective Premises Act Considerations

The Swiftplan Multiflex H12 is not classed as defective under the Defective Premises Act. However, due diligence is essential when purchasing such properties, as individual units may have undergone modifications or experienced wear and tear over the years. A thorough building survey is recommended to assess the condition and identify any potential issues.

Inspection Tips for Surveyors

When inspecting a Swiftplan Multiflex H12 property, surveyors should focus on the following areas:

• Timber Frame Condition: Check for signs of rot, insect damage, and moisture ingress in the timber frame. Use moisture meters and borescopes to assess hidden areas.

• Roof Integrity: Inspect the roof for signs of wear, leaks, and inadequate drainage. Pay special attention to flat roof variants, as they are more prone to water-related issues.

• Insulation and Ventilation: Evaluate the effectiveness of the existing insulation and ventilation systems. Consider recommending upgrades to improve energy efficiency and indoor air quality.

• External Cladding: Examine the condition of the render and steel weatherboarding. Look for cracks, corrosion, and other signs of deterioration that may require repair or replacement.

• Structural Stability: Assess the overall structural stability of the property, including the foundation, walls, and floors. Look for signs of settlement, cracking, or other structural issues.

Conclusion

The Swiftplan Multiflex H12 represents a unique chapter in the history of UK housing, offering a blend of mid-20th-century design and construction techniques. While these properties come with certain risks and maintenance requirements, they also offer potential for modernisation and energy efficiency improvements. For prospective buyers and investors, understanding the intricacies of the Swiftplan Multiflex H12 is crucial to making informed decisions and ensuring a sound investment.

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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