Historical Context and Manufacturing

The Crane House, a notable example of early 20th-century British architecture, was designed by Alderman Crane and constructed between 1925 and 1926. These properties, numbering around 400, were primarily built as detached and semi-detached bungalows. They are often found in suburban areas, reflecting the post-World War I housing boom aimed at providing affordable and efficient homes for the growing middle class.

The Crane House is a product of its time, embodying the architectural and construction trends of the early 20th century. The use of innovative materials and construction techniques was a hallmark of this period, driven by the need for rapid and cost-effective housing solutions. The designers and manufacturers of the Crane House aimed to create homes that were not only functional but also aesthetically pleasing, with features that set them apart from other properties of the era.

Identifying Characteristics

Recognizing a Crane House is relatively straightforward due to its distinctive features. These properties typically have a steep pitch hipped roof covered with asbestos cement pantiles, which was a common roofing material at the time. The generous overhanging eaves and the roughcast rendered external walls add to the unique appearance of these homes. Steel windows with PS surrounds and a recessed porch further distinguish the Crane House from other properties.

The use of asbestos cement pantiles for the roof was a practical choice, offering durability and resistance to weathering. However, it is important to note that asbestos is now known to pose significant health risks, which we will discuss in more detail later. The roughcast render on the external walls provided a textured finish that was both attractive and protective, helping to shield the underlying structure from the elements.

Construction Details

Substructure

The Crane House is built on a concrete raft foundation, which is thickened around the perimeter. This type of foundation provides a stable base for the property, distributing the weight evenly and reducing the risk of settlement. A damp-proof course (DPC) is included to prevent moisture from rising through the foundation and into the walls, which is crucial for maintaining the integrity of the structure.

Frame

The main frame of the Crane House consists of a combination of rolled steel angle (RSA) and rolled steel tee (RST) stanchions. Specifically, there are two double RSA corner stanchions, 15 RST stanchions, three RSA perimeter ties, five RST trusses, one RST hip truss, and RST hip and jack rafters. The frame is protected with a red oxide paint coating, which helps to prevent corrosion.

The use of steel in the frame provides strength and stability, allowing for the construction of larger and more open interior spaces. However, steel is susceptible to corrosion, particularly in areas where moisture can accumulate. This is a common issue in older properties and one that requires careful inspection and maintenance.

External Walls

The external walls of the Crane House are constructed from roughcast rendered hollow clinker concrete blocks. These blocks are fair-faced internally, meaning that the internal surfaces are left exposed rather than being covered with plaster or other finishes. This construction method provides a robust and durable exterior, but it can also lead to issues with cracking and spalling over time.

Separating Wall

The separating wall between properties is made from hollow plaster block cavity walls. This type of wall construction provides good sound insulation and helps to prevent the spread of fire between properties. In the roof space, profiled asbestos cement sheets are used, which again highlights the use of asbestos in the construction of the Crane House.

Partitions

Internal partitions are constructed from straw-reinforced plaster blocks and clinker concrete blocks around the fuel store. These materials were chosen for their availability and cost-effectiveness, but they can also be prone to cracking and other forms of deterioration over time.

Floors

The ground floor of the Crane House is made from concrete, providing a solid and durable base. There is no first floor in these properties, as they are single-storey bungalows.

Ceilings

Ceilings are constructed from asbestos cement panels supported by an RST ceiling support grid. This construction method provides a lightweight and fire-resistant ceiling, but it also poses health risks due to the presence of asbestos.

Roof

The roof of the Crane House is constructed with timber battens, bituminous felt, and asbestos cement pantiles. This combination of materials provides a weather-resistant and durable roof, but it also requires careful maintenance to prevent issues such as cracking and disintegration of the pantiles.

Typical Hazards and Risks

Asbestos

One of the most significant hazards associated with the Crane House is the presence of asbestos in the roofing materials and ceiling panels. Asbestos was widely used in construction during the early 20th century due to its fire-resistant properties and durability. However, it is now known to pose serious health risks, including lung cancer and mesothelioma, when the fibres are inhaled.

If you are considering purchasing a Crane House, it is essential to have a thorough asbestos survey conducted by a qualified professional. This will identify any asbestos-containing materials and provide recommendations for their safe removal or management.

Corrosion

Corrosion of the steel frame is another common issue in Crane Houses. Minor corrosion of the RSA and RST stanchions, particularly at the bases, and superficial corrosion of the roof trusses can compromise the structural integrity of the property. Regular inspections and maintenance are crucial to identify and address any signs of corrosion before they become serious problems.

Cracking

Cracking is a common issue in Crane Houses, affecting various parts of the property, including the render, hollow clinker blocks in the external walls, floor screeds, skirtings, window sills, and cast iron flue pipes. These cracks can be caused by a variety of factors, including settlement, thermal movement, and moisture ingress. It is important to have any cracks inspected by a qualified surveyor to determine their cause and recommend appropriate repairs.

Spalling

Spalling, or the breaking away of surface material, is another issue that can affect the clinker partition blocks in Crane Houses. This can be caused by moisture ingress, freeze-thaw cycles, or other forms of deterioration. Regular inspections and maintenance are essential to identify and address any signs of spalling before they lead to more serious structural issues.

Defective Premises Act

The Crane House is not classed as defective under the Defective Premises Act. However, it is important to be aware of the potential hazards and risks associated with these properties and to take appropriate steps to address them. Regular inspections and maintenance are crucial to ensure the safety and integrity of the property.

Inspection Checklist for Crane Houses

When inspecting a Crane House, it is important to pay close attention to the following areas:

Roof

• Check for any signs of cracking or disintegration of the asbestos cement pantiles.
• Inspect the roof trusses for any signs of corrosion.
• Look for any signs of moisture ingress or damage to the bituminous felt.

External Walls

• Inspect the roughcast render for any signs of cracking or deterioration.
• Check the hollow clinker concrete blocks for any signs of cracking or spalling.
• Look for any signs of moisture ingress or damage to the DPC.

Frame

• Inspect the RSA and RST stanchions for any signs of corrosion, particularly at the bases.
• Check the protective coating for any signs of deterioration.

Internal Partitions

• Inspect the straw-reinforced plaster blocks and clinker concrete blocks for any signs of cracking or deterioration.
• Check for any signs of moisture ingress or damage.

Floors

• Inspect the concrete floor for any signs of cracking or deterioration.
• Check for any signs of moisture ingress or damage.

Ceilings

• Inspect the asbestos cement panels for any signs of cracking or deterioration.
• Check the RST ceiling support grid for any signs of corrosion.

Windows and Doors

• Inspect the steel windows and PS surrounds for any signs of corrosion or damage.
• Check the recessed porch for any signs of cracking or deterioration.

Services

• Inspect the cast iron flue pipes for any signs of cracking or deterioration.
• Check the electrical and plumbing systems for any signs of damage or wear.

Maintenance and Repair Recommendations

Asbestos Management

If asbestos-containing materials are identified in the property, it is important to follow the recommendations of a qualified asbestos surveyor. This may include encapsulation, removal, or other management strategies to ensure the safety of the occupants.

Corrosion Prevention

Regular inspections and maintenance are crucial to prevent and address corrosion of the steel frame. This may include cleaning and repainting the protective coating, as well as addressing any areas of moisture ingress that could contribute to corrosion.

Crack Repair

Cracks in the render, hollow clinker blocks, floor screeds, skirtings, window sills, and cast iron flue pipes should be inspected by a qualified surveyor to determine their cause and recommend appropriate repairs. This may include filling and sealing the cracks, as well as addressing any underlying issues such as settlement or moisture ingress.

Spalling Repair

Spalling of the clinker partition blocks should be addressed promptly to prevent further deterioration. This may include removing and replacing the affected blocks, as well as addressing any underlying issues such as moisture ingress or freeze-thaw cycles.

Moisture Management

Effective moisture management is crucial to prevent issues such as corrosion, cracking, and spalling. This may include ensuring that the DPC is intact and functioning properly, addressing any areas of moisture ingress, and maintaining proper ventilation throughout the property.

Conclusion

The Crane House is a unique and historically significant property type that offers a range of benefits and challenges for home buyers and investors. By understanding the construction details, typical hazards and risks, and maintenance and repair recommendations, you can make informed decisions and ensure the long-term safety and integrity of your 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.