Historical Context and Origins

The Cook House, a distinctive type of system-built property, holds a unique place in the annals of British housing history. Manufactured by R Cook and Sons and designed by the architectural firms Clayton and Black, T Garratt and Son, and W H Overton, these homes were constructed in 1920. Only 14 of these properties were built, making them a rare find in today’s property market. Typically, these houses are located in suburban areas, often in semi-detached configurations.

Architectural Characteristics

External Features

Cook Houses are easily identifiable by their 2-storey semi-detached structure. They feature a medium pitch hipped roof covered with tiles, which is a common characteristic of homes from this period. The external walls are rendered with pebbledash, providing a textured finish that was popular in the early 20th century. A prominent PC canopy over the front door adds to the aesthetic appeal and functionality, offering some protection from the elements.

Internal Features

The internal construction details of Cook Houses are less well-documented. However, it is known that the ground floor is made of concrete. The specifics of the separating walls, partitions, first floor, and ceilings remain unknown, which can pose challenges during inspections and renovations.

Typical Hazards and Risks

Structural Concerns

One of the most common issues with Cook Houses is vertical cracking of the render between ground and first-floor openings. This type of cracking can indicate underlying structural problems, such as movement in the building’s foundation or issues with the concrete’s integrity.

Concrete Durability

The durability of the reinforced concrete used in Cook Houses has not been extensively investigated by the Building Research Establishment (BRE). However, general guidance on the inspection and assessment of reinforced concrete durability can be found in several BRE publications, including:

• Corrosion of Steel in Concrete (BRE Digest 444, Parts 1–3)
• Repair and Maintenance of Reinforced Concrete (BR 254)
• Carbonation Depths in Structural-Quality Concrete (BR 19)

These resources provide valuable insights into potential issues such as steel corrosion and carbonation, which can compromise the structural integrity of the property.

Defective Premises Act Considerations

The Defective Premises Act 1972 imposes a duty on builders, developers, and landlords to ensure that properties are constructed and maintained to a reasonable standard. While Cook Houses are not explicitly listed as defective under this Act, the potential structural issues and the age of the properties mean that they should be inspected thoroughly before purchase.

Inspection Guidelines for Surveyors

Preliminary Assessment

When inspecting a Cook House, start with a preliminary assessment of the external features. Look for signs of vertical cracking in the render, particularly between the ground and first-floor openings. Note any areas where the pebbledash render appears to be deteriorating or separating from the underlying concrete.

Detailed Structural Inspection

A detailed structural inspection should focus on the following areas:

• Foundation and Substructure: Although the specifics of the substructure are not known, look for signs of settlement or movement in the foundation. This can often be indicated by uneven floors or cracks in the walls.
• External Walls: Check the condition of the concrete and render. Look for signs of spalling, where the concrete surface flakes off, which can indicate deeper issues with the concrete’s integrity.
• Roof: Inspect the timber structure and tiles for signs of wear and tear. Ensure that the roof is watertight and that there are no missing or damaged tiles.
• Ground Floor: Examine the concrete ground floor for cracks or signs of moisture ingress. This can indicate issues with the damp-proof course or underlying foundation problems.

Specialist Testing

Given the potential issues with reinforced concrete, consider employing specialist testing methods to assess the condition of the concrete and steel reinforcement. Techniques such as carbonation testing and half-cell potential measurements can provide valuable insights into the durability and integrity of the concrete.

Typical Construction Details

Roof

The roof of a Cook House is typically constructed from timber and covered with tiles. The medium pitch hipped design is both aesthetically pleasing and functional, providing good drainage and resistance to wind uplift. However, the timber structure can be susceptible to rot and insect infestation, particularly if there are any leaks or issues with the roof covering.

Walls

The external walls are made of concrete and covered with a pebbledash render. This type of construction provides good thermal mass and durability, but it can be prone to cracking and spalling. The render can also deteriorate over time, particularly if it is not properly maintained.

Floors

The ground floor is constructed from concrete, which provides a solid and durable base. However, concrete floors can be prone to cracking, particularly if there are issues with the foundation or damp-proof course. The specifics of the first floor construction are not known, but it is likely to be a timber structure, which can be susceptible to issues such as rot and insect infestation.

Main Frame

The main frame of a Cook House is likely to be constructed from reinforced concrete, given the period and construction methods used. This provides a strong and durable structure, but it can be prone to issues such as steel corrosion and carbonation, which can compromise the integrity of the concrete.

Common Defects in Cook Houses

Vertical Cracking

As previously mentioned, vertical cracking of the render between ground and first-floor openings is a common issue in Cook Houses. This can indicate underlying structural problems, such as movement in the foundation or issues with the concrete’s integrity.

Spalling

Spalling, where the concrete surface flakes off, is another common issue. This can be caused by a variety of factors, including freeze-thaw cycles, corrosion of the steel reinforcement, and carbonation of the concrete. Spalling can compromise the structural integrity of the property and should be addressed promptly.

Damp and Moisture Ingress

Damp and moisture ingress can be a significant issue in older properties, including Cook Houses. This can be caused by a variety of factors, including issues with the damp-proof course, leaks in the roof, and poor ventilation. Damp can lead to a range of problems, including rot, mould, and structural damage.

Roof Issues

The timber roof structure can be susceptible to rot and insect infestation, particularly if there are any leaks or issues with the roof covering. Regular maintenance and inspections are essential to ensure the roof remains in good condition.

Maintenance and Repair Recommendations

Regular Inspections

Regular inspections are essential to identify and address any issues before they become significant problems. This should include a thorough inspection of the roof, walls, floors, and foundation, as well as specialist testing of the concrete and steel reinforcement.

Addressing Cracks and Spalling

Any cracks or spalling in the concrete should be addressed promptly to prevent further deterioration. This may involve repairing or replacing the affected areas, as well as addressing any underlying issues, such as steel corrosion or carbonation.

Damp and Moisture Control

Addressing damp and moisture ingress is essential to prevent issues such as rot, mould, and structural damage. This may involve repairing or replacing the damp-proof course, addressing any leaks in the roof, and improving ventilation.

Roof Maintenance

Regular maintenance of the roof is essential to ensure it remains in good condition. This should include inspecting and repairing any damaged or missing tiles, as well as addressing any issues with the timber structure.

Conclusion

The Cook House is a unique and distinctive type of system-built property with a rich history and a range of architectural features. However, these properties can also be prone to a range of issues, including vertical cracking, spalling, damp, and roof problems. Regular inspections and maintenance are essential to ensure these properties remain in good condition and to address any issues promptly.

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.