Overview of the Skarne House

The Skarne house, a notable example of system-built properties, emerged in the 1960s as a solution to the post-war housing shortage in the UK. Designed by George Bowie and manufactured by Crudens Ltd, these properties were constructed with efficiency and cost-effectiveness in mind. With approximately 4,050 units built, the Skarne house remains a significant part of the UK’s architectural landscape. Known alternatively as Cruden houses, these properties include bungalows and two- and three-storey terraced houses, as well as flats.

Typical Characteristics and Identification

Architectural Features

Skarne houses are easily identifiable by their distinctive architectural features. They typically have flat roofs covered with asphalt, which was a common roofing material during the period of their construction. The front and rear external walls are either timber boarding or exposed aggregate textured precast concrete (PC) panels, while the flank walls are constructed of brick. These materials were chosen for their availability and ease of assembly, aligning with the rapid construction methods of the time.

Common Variants

While the basic design of Skarne houses remains consistent, there are some variants. For instance, some models feature external walls made of exposed aggregate textured PC sandwich panels. Additionally, the storey-height PC panel cavity separating walls are a notable variant in some Skarne houses.

Construction Details

Substructure

The substructure of Skarne houses typically includes a precast reinforced concrete (PRC) ground beam and a concrete slab. A damp-proof course (DPC) is also incorporated to prevent moisture ingress from the ground.

External Walls

The front and rear walls are constructed using storey-height timber frame panels, which are clad with timber boarding and lined with plasterboard. Between the frame studs, 3/4″ polystyrene insulation is used to provide thermal efficiency. The walls also include hessian-based bituminous felt and tanalised timber sills. Fire safety is addressed with 1″ Asbestolux fire stops and galvanised steel cleats for structural stability.

Flank Walls

The flank walls are built with brick, featuring a cavity filled with 1/2″ polystyrene insulation. Storey-height PC panels are seated on a mortar bed, with zinc fire stops and cement mortar beds providing additional structural integrity. Timber wall plates and aluminium trims are also used in the construction of these walls.

Separating Walls and Partitions

Separating walls in Skarne houses are constructed using storey-height room-sized PC panels with shear keys at vertical joints. Internal partitions are made from storey-height 4 3/4″ PC panels seated on mortar beds, ensuring robust internal division.

Floors and Ceilings

The ground floor is typically a concrete slab, while the first floor consists of PC floor slabs. Ceilings are lined with plasterboard, providing a smooth finish and additional fire resistance.

Roof

The roof structure comprises PC roof slabs covered with asphalt. This design, while efficient, has been known to present certain challenges over time, particularly with water ingress and drainage issues.

Typical Hazards and Risks

Structural Issues

One of the primary concerns with Skarne houses is the cracking and spalling of concrete components. This can be attributed to the high rates of carbonation and significant chloride content in the PC panels. Additionally, the steel ties used in the construction are prone to severe corrosion, which can compromise the structural integrity of the property.

Water Ingress

Rain penetration through the asphalt roof membrane is a common issue in Skarne houses. Defective internal roof drainage pipes exacerbate this problem, leading to potential water damage within the property.

Asbestos

Asbestolux, a material containing asbestos, is used in the walls of Skarne houses. While it was a common building material at the time, asbestos is now known to pose significant health risks. Proper management and, if necessary, removal of asbestos-containing materials are crucial for ensuring the safety of occupants.

Fire Safety

The use of Asbestolux fire stops and other fire-resistant materials provides some level of fire safety. However, the overall fire resistance of the property should be assessed, particularly if any modifications or renovations have been made over the years.

Defective Premises Act Considerations

Under the Defective Premises Act, properties that are deemed defective may require significant repairs or even demolition. Skarne houses, due to their age and the materials used in their construction, may fall under this category. It is essential for potential buyers and investors to conduct thorough surveys and assessments to determine the extent of any defects and the associated costs of remediation.

Inspection Guide for Surveyors

External Inspection

1. Roof: Check for signs of water ingress, particularly around the asphalt membrane. Inspect internal roof drainage pipes for defects.
2. Walls: Look for cracking and spalling in concrete components. Assess the condition of timber boarding and PC panels.
3. Flank Walls: Inspect brickwork for signs of deterioration. Check for insulation integrity and any signs of moisture ingress.

Internal Inspection

1. Floors: Examine concrete slabs for cracks or signs of movement. Check PC floor slabs for structural integrity.
2. Walls: Look for signs of corrosion in steel ties. Assess the condition of Asbestolux fire stops and other fire-resistant materials.
3. Ceilings: Inspect plasterboard for any signs of water damage or structural issues.

Asbestos Management

1. Identification: Identify any materials containing asbestos, particularly in walls and fire stops.
2. Assessment: Conduct a risk assessment to determine the condition of asbestos-containing materials.
3. Management: Develop a management plan for asbestos, including potential removal or encapsulation.

Structural Assessment

1. Carbonation and Chloride Content: Test concrete components for carbonation and chloride content to assess the risk of spalling and corrosion.
2. Steel Ties: Inspect steel ties for signs of corrosion and assess their impact on structural integrity.

Typical Defects in Skarne Houses

Cracking and Spalling

Cracking and spalling of concrete components are common defects in Skarne houses. These issues can compromise the structural integrity of the property and may require significant repairs.

Corroded Steel Ties

The steel ties used in the construction of Skarne houses are prone to corrosion, particularly in areas with high chloride content. This can lead to structural instability and may necessitate the replacement of corroded ties.

Water Ingress

Water ingress through the asphalt roof membrane and defective internal roof drainage pipes is a frequent issue. This can lead to water damage within the property and may require repairs to the roof and drainage system.

Asbestos-Related Issues

The presence of Asbestolux in the walls poses a significant health risk. Proper management and, if necessary, removal of asbestos-containing materials are essential to ensure the safety of occupants.

Conclusion

The Skarne house, with its distinctive architectural features and efficient construction methods, remains a significant part of the UK’s housing stock. However, potential buyers and investors must be aware of the typical hazards and risks associated with these properties. Thorough inspections and assessments are crucial to identify and address any defects, ensuring the safety and longevity of the property.

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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