Historical Context and Background

The Coventry Corporation house, also known as the Radiation House, is a unique and rare example of post-war British architecture. Designed by Donald E. Gibson and Eric Neel, these properties were constructed in 1945, immediately following the end of World War II. Only two of these houses were ever built, making them a rare find in the UK property market. These homes were part of the broader effort to address the housing shortage caused by wartime destruction and the need for rapid, cost-effective construction methods.

Manufacturers and Designers

The Coventry Corporation, a local government body, was responsible for the construction of these houses. The design was the brainchild of Donald E. Gibson and Eric Neel, who were prominent figures in the field of architecture and urban planning during that era. Their design aimed to provide a quick and efficient solution to the housing crisis, utilizing innovative materials and construction techniques.

Typical Characteristics of Coventry Corporation Houses

Structural Design

Coventry Corporation houses are two-storey, semi-detached properties. They feature a shallow pitch gable roof covered with profiled asbestos cement tiles. The front and rear external walls are constructed from precast concrete (PC) panels up to the first-floor window sill level, with asbestos cement sheets above. The gable walls are entirely made of PC panels.

Construction Details

Substructure

The substructure consists of concrete strip footings with PC underbuilding at the corners. The perimeter is infilled with a suspended PC apron, and a damp-proof course (DPC) is included to prevent moisture ingress.

Frame

The frame is composed of a steel setting out sill around the perimeter, 30 tubular steel stanchions, four tubular steel lattice perimeter beams, 18 tubular steel lattice floor support beams, and nine tubular steel roof trusses. The entire frame is coated with red oxide paint for protection against corrosion.

External Walls

The front and rear walls are made of PC panels up to the first-floor window sill level, with asbestos cement sheets above. The gable walls are entirely constructed from PC panels. The cavity walls are timber-framed, infilled with wood wool, and lined with plasterboard.

Separating Wall

The separating wall between the semi-detached units is a PC panel cavity wall, faced with timber framing, infilled with wood wool, and lined with plasterboard.

Partitions

Internal partitions are timber frame panels, infilled with wood wool, and lined with plasterboard.

Floors

The ground floor consists of suspended PRC panels, while the first floor is made of plywood on timber battens.

Ceilings

Ceilings are constructed from fibreboard.

Roof

The roof is covered with profiled asbestos cement tiles.

Variants

Some variants of these houses feature a protective coating of red oxide and aluminium paint. Additionally, tongue and groove (T&G) boarding on timber battens may be used for the first floor.

Typical Hazards and Risks

Corrosion

One of the most significant issues with Coventry Corporation houses is the severe corrosion of tubular steel stanchions, particularly at their bases. This corrosion can compromise the structural integrity of the property, making it a critical area for inspection.

Steel Setting Out Sill

The steel setting out sill around the perimeter is also prone to severe corrosion. This can lead to structural weaknesses and potential safety hazards.

Deterioration of Pointing

The pointing between PC panel joints often deteriorates over time, leading to gaps and potential water ingress. This can cause further damage to the structure and internal finishes.

Mould Growth

Mould growth on the underside of asbestos cement roof tiles is a common issue. This not only affects the aesthetic appeal of the property but can also pose health risks to the occupants.

Cracking and Spalling

Cracking and spalling of the PC underbuilding are typical defects. These issues can lead to further structural problems if not addressed promptly.

Defective Premises Act

Coventry Corporation houses are not classified as defective under the Defective Premises Act. However, the unique construction materials and methods used in these properties require careful inspection and maintenance to ensure their longevity and safety.

Inspection Guide for Surveyors

When inspecting a Coventry Corporation house, surveyors should pay close attention to the following areas:

Tubular Steel Stanchions

Check for severe corrosion, particularly at the bases. Use a moisture meter to detect any hidden moisture that could accelerate corrosion.

Steel Setting Out Sill

Inspect the steel setting out sill around the perimeter for signs of severe corrosion. Look for any areas where the protective red oxide paint has worn away, exposing the steel to the elements.

Pointing Between PC Panel Joints

Examine the pointing between PC panel joints for signs of deterioration. Look for gaps, cracks, or loose mortar that could allow water ingress.

Asbestos Cement Roof Tiles

Inspect the underside of asbestos cement roof tiles for mould growth. Use a torch to check for any hidden mould that may not be immediately visible.

PC Underbuilding

Check for cracking and spalling of the PC underbuilding. Use a hammer to tap the surface and listen for hollow sounds that could indicate internal voids or weaknesses.

Protective Coating

Inspect the protective coating of red oxide paint on the steel frame. Look for areas where the paint has worn away or flaked off, exposing the steel to potential corrosion.

Typical Defects and Maintenance Tips

Corrosion Prevention

To prevent corrosion of the tubular steel stanchions and steel setting out sill, ensure that the protective red oxide paint is maintained in good condition. Reapply the paint as needed to provide a barrier against moisture and oxygen.

Pointing Maintenance

Regularly inspect the pointing between PC panel joints and repair any areas of deterioration. Use a high-quality mortar mix to fill gaps and cracks, ensuring a watertight seal.

Mould Control

To control mould growth on asbestos cement roof tiles, ensure that the roof space is well-ventilated. Use a dehumidifier if necessary to reduce moisture levels. Clean any visible mould with a suitable fungicidal solution.

Crack and Spall Repair

Repair any cracks and spalling in the PC underbuilding promptly. Use a suitable concrete repair product to fill cracks and restore the structural integrity of the underbuilding.

Conclusion

Coventry Corporation houses are a unique and rare example of post-war British architecture. While they offer a fascinating glimpse into the innovative construction methods of the time, they also present several challenges for home buyers and investors. Understanding the typical characteristics, hazards, and maintenance requirements of these properties is essential for making an informed decision.

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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