Overview of the Lecaplan Type A House

The Lecaplan Type A house, a product of the 1960s, represents a significant chapter in the history of British residential architecture. Designed by J.C. Tilley and Stanley Bragg & Associates and manufactured by W & C French Ltd, these homes were part of a broader movement towards system-built properties. With approximately 1,600 units constructed, these houses are primarily found in various parts of the UK, often in suburban settings.

Historical Context and Manufacturing Details

Period and Location

The Lecaplan Type A houses were built during the 1960s, a period marked by a housing boom in the UK. This era saw a significant push towards the construction of affordable and quickly assembled homes to address the post-war housing shortage. These properties are typically located in suburban areas, where there was ample space for new housing developments.

Manufacturers and Designers

The Lecaplan Type A house was manufactured by W & C French Ltd, a company known for its expertise in prefabricated construction. The design was the brainchild of J.C. Tilley and Stanley Bragg & Associates, who were prominent figures in the architectural world during that time. Their collaboration resulted in a design that was both innovative and practical, meeting the needs of the era.

Typical Characteristics of the Lecaplan Type A House

Structural Features

The Lecaplan Type A house is a two-storey terraced property with a shallow pitch gable roof covered with concrete tiles. The external walls are constructed using Leca PC (precast concrete) panels, which are either used throughout or combined with timber shiplap boarding. The gable walls are made of storey-height Leca PC panels, with the apex featuring horizontal timber boarding.

Internal Layout

Internally, these houses typically feature a concrete ground floor and a first floor made of tongue-and-groove (T&G) chipboard on timber joists. The ceilings are plasterboard, and the partitions are timber stud lined with plasterboard. The separating walls between properties are also made of storey-height Leca PC panels.

Insulation and Finishes

The Lecaplan Type A houses were designed with polystyrene insulation between the frame studs, providing a basic level of thermal efficiency. The internal walls are sheathed with hardboard and lined with plasterboard backed with a polyethylene vapour control layer. This construction method aimed to provide a balance between cost-effectiveness and comfort.

Typical Hazards and Risks

Structural Issues

One of the primary concerns with Lecaplan Type A houses is the potential for structural issues. Over time, the first-floor gable PC panels can bow, and diagonal cracking may appear at the base of these panels. These issues can compromise the structural integrity of the property and may require significant repairs.

Insulation and Dampness

The insulation used in these houses, while adequate for the time, may not meet modern standards. Polystyrene insulation can degrade over time, leading to reduced thermal efficiency and potential dampness issues. The presence of a polyethylene vapour control layer helps mitigate this risk, but it is still a consideration for potential buyers.

Roof and Wall Integrity

The shallow pitch gable roof, while aesthetically pleasing, can be prone to issues such as tile displacement and water ingress. Additionally, the combination of Leca PC panels and timber shiplap boarding in the external walls can lead to differential movement, which may cause cracking and other structural issues.

Defective Premises Act Considerations

The Lecaplan Type A house is not classed as defective under the Defective Premises Act. However, it is essential to note that this does not mean the property is free from issues. Potential buyers should be aware of the typical defects associated with this type of construction and ensure a thorough survey is conducted before purchase.

Inspection Guide for Lecaplan Type A Houses

External Inspection

Roof

• Check for Tile Displacement: Inspect the concrete tiles for any signs of displacement or damage. The shallow pitch of the roof can make it more susceptible to wind damage.
• Inspect Gable Ends: Look for any signs of bowing or cracking in the gable PC panels. Diagonal cracks at the base of these panels are a common issue.

Walls

• Examine Leca PC Panels: Check for any signs of cracking or movement in the Leca PC panels. Pay particular attention to the joints between panels.
• Inspect Timber Shiplap Boarding: Look for any signs of rot or damage in the timber shiplap boarding. Ensure that the timber is adequately treated and maintained.

Internal Inspection

Floors

• Check for Unevenness: Inspect the concrete ground floor and the T&G chipboard first floor for any signs of unevenness or movement. This can indicate underlying structural issues.
• Inspect Joists and Slabs: Ensure that the timber joists and PC floor slabs are in good condition and securely fixed.

Walls and Partitions

• Examine for Cracks: Look for any signs of cracking in the internal walls, particularly around doorways and windows. This can indicate movement in the structure.
• Check Insulation: If possible, inspect the insulation between the frame studs. Ensure that it is in good condition and has not degraded over time.

Additional Considerations

Dampness

• Check for Signs of Damp: Look for any signs of dampness or mould, particularly in areas with poor ventilation. This can indicate issues with the insulation or vapour control layer.
• Inspect DPC: Ensure that the damp-proof course (DPC) is intact and functioning correctly. This is crucial for preventing rising damp.

Services

• Inspect Plumbing and Electrical Systems: Ensure that the plumbing and electrical systems are up to modern standards. These systems may need updating in older properties.

Typical Construction Details

Substructure

The substructure of the Lecaplan Type A house consists of concrete pads and PC ground beams, supporting a concrete slab. A damp-proof course (DPC) is included to prevent rising damp.

External Walls

The external walls are constructed using Leca PC panels, either throughout or combined with timber shiplap boarding. The panels are sheathed externally with plywood overlaid with building paper and clad with shiplap timber boarding. Internally, the walls are sheathed with hardboard and lined with plasterboard backed with a polyethylene vapour control layer. Polystyrene insulation is placed between the frame studs.

Gable Walls

The gable walls are made of storey-height Leca PC panels bolted to column panels. The apex of the gable is constructed using horizontal timber boarding on a timber frame fixed to the PC panel.

Separating Walls and Partitions

The separating walls between properties are made of storey-height Leca PC panels. Internal partitions are constructed using timber studs lined with plasterboard.

Floors

The ground floor is a concrete slab, while the first floor is made of T&G chipboard on timber joists, seated on the rebated head of the ground floor wall panels.

Ceilings and Roof

The ceilings are plasterboard, and the roof is constructed using timber trussed rafters covered with concrete tiles.

Typical Defects in Lecaplan Type A Houses

Structural Defects

• Bowing of Gable Panels: The first-floor gable PC panels can bow over time, leading to structural instability.
• Cracking: Diagonal cracking at the base of the gable PC panels is a common issue, indicating movement in the structure.

Insulation and Dampness Issues

• Degraded Insulation: The polystyrene insulation used in these houses can degrade over time, leading to reduced thermal efficiency and potential dampness issues.
• Dampness: Poor ventilation and degraded insulation can lead to dampness and mould growth, particularly in areas with poor ventilation.

Roof and Wall Issues

• Tile Displacement: The shallow pitch gable roof can be prone to tile displacement and water ingress.
• Differential Movement: The combination of Leca PC panels and timber shiplap boarding in the external walls can lead to differential movement, causing cracking and other structural issues.

Conclusion

The Lecaplan Type A house is a fascinating example of mid-20th-century British residential architecture. While these properties offer a unique charm and historical significance, potential buyers must be aware of the typical defects and risks associated with this type of construction. A thorough survey is essential to identify any issues and ensure the property is 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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