Overview of the Span Type K House

The Span Type K house, a product of the innovative post-war British housing boom, stands as a testament to the architectural ingenuity of the 1960s. Designed by the renowned architect Eric Lyons and manufactured by Span Developments Ltd, these properties were constructed between 1967 and 1969. With a total of 341 units built, the Span Type K houses are primarily located in suburban areas, offering a unique blend of modernist design and practical living spaces.

Historical Context and Design Philosophy

The Vision of Eric Lyons and Span Developments Ltd

Eric Lyons, a visionary architect, aimed to create homes that were not only aesthetically pleasing but also functional and community-oriented. Span Developments Ltd, the company behind the construction, shared this vision and sought to revolutionize the housing market by offering affordable yet stylish homes. The Span Type K house is a prime example of this philosophy, combining innovative design with practical features.

Period of Construction and Typical Locations

Constructed between 1967 and 1969, the Span Type K houses are predominantly found in suburban areas across the UK. These locations were chosen to provide residents with a peaceful living environment while still being within commuting distance of major cities. The design of these homes reflects the modernist architectural trends of the time, characterized by clean lines, open spaces, and an emphasis on natural light.

Identification Characteristics

Architectural Features

The Span Type K houses are easily identifiable by their distinctive architectural features. These include:

• Terraced Bungalows and Houses: The properties are available in both single-storey bungalows and two- to three-storey terraced houses.
• Roof Design: The roofs are typically shallow pitch monopitch or double monopitch of sawtooth section, covered with asbestos cement slates.
• External Walls: The external walls are constructed from a combination of brick, painted asbestos cement sheet, asbestos cement slate hanging, or painted vertical timber boarding.
• Entrance Porch: Most dwellings feature a single-storey entrance porch clad in stained vertical timber boarding with a flat roof.
• Rear Extensions: Some properties have single-storey rear extensions with flat or monopitch roofs.

Materials Used

The materials used in the construction of Span Type K houses were chosen for their durability and cost-effectiveness. These include:

• Asbestos Cement Slates: Used for roofing and external cladding.
• Brick: Used for gable walls and some external walls.
• Timber Boarding: Used for external cladding and entrance porches.
• Concrete: Used for ground floors.
• Plasterboard: Used for internal partitions and ceilings.

Typical Construction Details

Substructure

The specific details of the substructure for Span Type K houses are not well-documented. However, it is likely that they were built on traditional concrete foundations, which were common during the period of construction.

Frame

The main frame of the Span Type K houses consists of coupled RS A-frames placed centrally on the plan. The protective coating used for the frame is not known, but it is likely that some form of anti-corrosive treatment was applied to ensure longevity.

External Walls

The external walls are constructed from timber frame panels with various cladding materials, including:

• Asbestos Cement: Used for lower levels and some upper levels.
• Brick: Used for gable walls and some external walls.
• Vertical Timber Boarding: Used for both lower and upper levels.

Separating Walls

The separating walls between properties are constructed from brick and faced externally with 9-inch wide painted asbestos cement panels. This design provides both structural integrity and sound insulation.

Partitions

Internal partitions are made from timber stud lined with plasterboard, providing a lightweight and flexible solution for dividing internal spaces.

Floors

• Ground Floor: Constructed from concrete, providing a solid and durable base.
• First Floor: Made from timber panels, offering a lightweight and flexible solution.

Ceilings

Ceilings are constructed from plasterboard, providing a smooth and easily finished surface.

Roof

The roof design varies depending on the specific property:

• Pitched Roof: Constructed from timber panels on timber purlins, covered with asbestos-cement slates.
• Flat Roof: Made from timber panels and bituminous felt, providing a cost-effective and easily maintained solution.

Typical Hazards and Risks

Asbestos-Related Risks

One of the most significant hazards associated with Span Type K houses is the presence of asbestos in the construction materials. Asbestos cement slates and panels were commonly used for roofing and external cladding. While asbestos is generally safe when intact, it can pose serious health risks if disturbed or damaged, releasing harmful fibres into the air.

Structural Integrity

The use of timber frames and panels in the construction of Span Type K houses can lead to issues with structural integrity over time. Timber is susceptible to rot, insect infestation, and warping, which can compromise the stability of the property.

Moisture and Damp

The design and materials used in Span Type K houses can make them prone to moisture ingress and damp issues. This is particularly true for properties with flat roofs, which can be more susceptible to water pooling and leaks.

Insulation and Energy Efficiency

The insulation and energy efficiency of Span Type K houses may not meet modern standards. The use of timber and asbestos cement panels can result in poor thermal performance, leading to higher energy bills and a less comfortable living environment.

Defective Premises Act Considerations

The Span Type K 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. It is essential to identify any potential defects and assess the cost of necessary repairs or renovations.

Inspection Guide for Surveyors

Pre-Inspection Preparation

Before conducting an inspection of a Span Type K house, it is essential to gather as much information as possible about the property. This includes reviewing any available documentation, such as previous surveys, maintenance records, and planning permissions.

External Inspection

• Roof: Check for any signs of damage or deterioration to the asbestos cement slates. Look for missing or broken slates, as well as any signs of water ingress or leaks.
• External Walls: Inspect the condition of the cladding materials, including asbestos cement panels, brickwork, and timber boarding. Look for any signs of damage, rot, or deterioration.
• Entrance Porch: Check the condition of the timber boarding and flat roof. Look for any signs of rot, water damage, or structural issues.
• Rear Extensions: Inspect the condition of any rear extensions, paying particular attention to the roof and cladding materials.

Internal Inspection

• Partitions: Check the condition of internal partitions, looking for any signs of damage, damp, or structural issues.
• Floors: Inspect the condition of the ground and first floors. Look for any signs of movement, cracking, or deterioration.
• Ceilings: Check the condition of the plasterboard ceilings, looking for any signs of water damage, cracking, or sagging.
• Asbestos: Identify any areas where asbestos materials are present. Ensure that these materials are intact and not damaged. If any asbestos is found to be damaged, it is essential to arrange for its safe removal by a licensed professional.

Structural Inspection

• Frame: Inspect the condition of the timber frame, looking for any signs of rot, insect infestation, or structural issues. Pay particular attention to areas where the frame may be exposed to moisture.
• Separating Walls: Check the condition of the brick separating walls and asbestos cement panels. Look for any signs of cracking, movement, or deterioration.

Moisture and Damp

• Roof: Check for any signs of water ingress or leaks in the roof. Pay particular attention to flat roofs, which can be more susceptible to water pooling and leaks.
• External Walls: Look for any signs of damp or moisture ingress in the external walls. Pay particular attention to areas where different materials meet, as these can be more prone to water penetration.
• Internal Walls and Floors: Check for any signs of damp or moisture ingress in internal walls and floors. Look for any signs of mould, staining, or musty odours.

Insulation and Energy Efficiency

• Insulation: Check the condition of any insulation materials present in the property. Look for any signs of deterioration or damage.
• Energy Efficiency: Assess the overall energy efficiency of the property. Consider the age and condition of the heating system, windows, and doors. Look for any signs of draughts or poor thermal performance.

Common Defects in Span Type K Houses

Asbestos-Related Issues

As previously mentioned, the presence of asbestos in the construction materials of Span Type K houses can pose significant health risks if disturbed or damaged. It is essential to identify and safely manage any asbestos materials present in the property.

Structural Issues

The use of timber frames and panels in the construction of Span Type K houses can lead to issues with structural integrity over time. Common defects include:

• Rot: Timber is susceptible to rot, particularly in areas exposed to moisture. Look for any signs of decay or deterioration in the timber frame and panels.
• Insect Infestation: Timber can also be vulnerable to insect infestation, such as woodworm. Look for any signs of insect activity or damage.
• Warping: Timber can warp over time, particularly if exposed to moisture. Look for any signs of movement or distortion in the timber frame and panels.

Moisture and Damp Issues

The design and materials used in Span Type K houses can make them prone to moisture ingress and damp issues. Common defects include:

• Roof Leaks: Flat roofs can be particularly susceptible to water pooling and leaks. Look for any signs of water ingress or damage to the roof.
• Damp Walls: The use of different cladding materials can create weak points where water can penetrate. Look for any signs of damp or moisture ingress in the external walls.
• Internal Damp: Moisture ingress can also affect internal walls and floors. Look for any signs of damp, mould, or musty odours.

Insulation and Energy Efficiency Issues

The insulation and energy efficiency of Span Type K houses may not meet modern standards. Common defects include:

• Poor Insulation: The use of timber and asbestos cement panels can result in poor thermal performance. Look for any signs of inadequate insulation or draughts.
• Inefficient Heating Systems: Older heating systems may not be as efficient as modern alternatives. Consider the age and condition of the heating system and look for any signs of inefficiency.

Conclusion

The Span Type K house is a unique and innovative example of post-war British architecture. Designed by Eric Lyons and manufactured by Span Developments Ltd, these properties offer a blend of modernist design and practical living spaces. However, potential buyers should be aware of the typical hazards and risks associated with these properties, including the presence of asbestos, structural issues, and moisture ingress.

When considering the purchase of a Span Type K house, it is essential to conduct a thorough survey to identify any potential defects and assess the cost of necessary repairs or renovations. By doing so, buyers can ensure that they are making a sound investment and safeguarding their future 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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