Historical Context and Background

The Kirton house, a distinctive property type, emerged in the 1920s as part of the UK’s post-World War I housing boom. These homes were designed to address the acute housing shortage and were constructed using innovative methods and materials for the time. The Kirton house is a two-storey terraced house, characterized by its medium pitch hipped roof covered with concrete tiles and rendered external walls. Only eight of these houses were built, making them a rare find in today’s property market.

Manufacturer and Designer

The exact manufacturer and designer of the Kirton house remain somewhat obscure, as these homes were part of a broader movement of system-built properties during the early 20th century. However, it is known that these houses were constructed using reinforced concrete, a material that was gaining popularity for its durability and fire resistance. The design and construction methods were likely influenced by the need for rapid, cost-effective housing solutions.

Typical Locations

Kirton houses are typically found in urban and suburban areas where there was a high demand for affordable housing in the 1920s. These properties are often located in regions that experienced significant industrial growth during the early 20th century, such as the Midlands and Northern England. Their presence in these areas reflects the historical context of post-war reconstruction and the need to house a growing workforce.

Characteristics and Features

External Features

Kirton houses are easily identifiable by their medium pitch hipped roofs covered with concrete tiles. The external walls are rendered throughout, providing a uniform and somewhat austere appearance. One of the distinctive features of these homes is the rebated window reveals, designed to accommodate window frames seamlessly. This design choice not only enhances the aesthetic appeal but also contributes to the structural integrity of the property.

Internal Features

Internally, Kirton houses feature timber boarding on timber joists for both the ground and first floors. The ceilings’ construction details are not well-documented, but they are likely to be consistent with the timber-based construction methods of the time. The partitions within the house are made of concrete, providing robust internal walls that contribute to the overall durability of the structure.

Structural Elements

The main frame of the Kirton house consists of reinforced concrete, a material chosen for its strength and longevity. The substructure includes concrete strip footings and a damp-proof course (DPC) to prevent moisture ingress. The external walls are 9-inch thick concrete with cast-in tapered vertical and horizontal ventilation cavities, which help to manage moisture and air flow within the structure. Integral concrete corbels support the first-floor joists, and the window sills are also made of concrete, providing a cohesive and sturdy construction.

Typical Hazards and Risks

Structural Integrity

One of the primary concerns with Kirton houses is the potential for structural issues related to the reinforced concrete. Over time, concrete can suffer from carbonation, a process where carbon dioxide from the air penetrates the concrete and reduces its alkalinity. This can lead to the corrosion of the steel reinforcement within the concrete, compromising the structural integrity of the property.

Moisture Ingress

The ventilation cavities and air inlet/outlet holes in the external walls are designed to manage moisture, but they can also be points of vulnerability. If these cavities become blocked or if the DPC fails, moisture can penetrate the walls, leading to damp and mould issues. This is particularly concerning in older properties where maintenance may have been neglected.

Thermal Efficiency

Kirton houses, like many properties from the early 20th century, may not meet modern standards for thermal efficiency. The concrete walls, while durable, can be poor insulators, leading to higher heating costs and potential issues with condensation. Retrofitting these homes with modern insulation can be challenging and may require significant investment.

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 the Kirton house is not specifically listed as defective under this act, the potential issues with reinforced concrete and moisture ingress mean that buyers and investors should exercise caution. A thorough survey by a qualified professional is essential to identify any defects and assess the overall condition of the property.

Inspection Guide for Surveyors

Preliminary Assessment

When inspecting a Kirton house, start with a preliminary assessment of the external features. Look for any visible signs of damage or deterioration in the concrete tiles and rendered walls. Pay particular attention to the rebated window reveals and the condition of the window frames.

Structural Inspection

Next, conduct a detailed structural inspection. Check the condition of the concrete strip footings and the DPC. Look for any signs of moisture ingress or dampness in the external walls. Use a moisture meter to assess the moisture levels in the walls and floors. Inspect the ventilation cavities and air inlet/outlet holes to ensure they are clear and functioning correctly.

Internal Inspection

Inside the property, examine the timber boarding and joists for any signs of rot or damage. Check the condition of the concrete partitions and look for any cracks or signs of movement. Use a borescope to inspect the condition of the steel reinforcement within the concrete, if possible. Pay attention to any signs of carbonation or corrosion.

Roof Inspection

Finally, inspect the roof structure. Check the condition of the timber rafters and purlins, and look for any signs of water ingress or damage to the concrete tiles. Ensure that the roof is adequately ventilated and that there are no signs of condensation or mould.

Typical Construction Details

Roof

The roof of a Kirton house is constructed with timber rafters and purlins, covered with concrete tiles. The medium pitch hipped design provides a distinctive appearance and helps to shed water effectively. However, the concrete tiles can become brittle over time and may require replacement.

Walls

The external walls are 9-inch thick concrete with cast-in tapered vertical and horizontal ventilation cavities. These walls are rendered throughout, providing a uniform appearance and additional protection against the elements. The integral concrete corbels support the first-floor joists, and the window sills are also made of concrete.

Floors

The ground and first floors are constructed with timber boarding on timber joists. This provides a solid and stable floor structure, but the timber elements can be susceptible to rot and insect damage if not properly maintained.

Main Frame

The main frame of the Kirton house is made of reinforced concrete, providing a strong and durable structure. However, the steel reinforcement within the concrete can be vulnerable to corrosion if the concrete becomes carbonated or if moisture penetrates the structure.

Common Defects

Concrete Degradation

One of the most common defects in Kirton houses is the degradation of the concrete. Over time, the concrete can suffer from carbonation, leading to the corrosion of the steel reinforcement. This can compromise the structural integrity of the property and may require significant repairs.

Moisture Issues

Moisture ingress is another common issue, particularly if the ventilation cavities and air inlet/outlet holes become blocked. This can lead to damp and mould problems, which can affect the health of the occupants and the overall condition of the property.

Timber Decay

The timber elements of the Kirton house, including the floor joists and roof rafters, can be susceptible to rot and insect damage. Regular inspections and maintenance are essential to ensure that these elements remain in good condition.

Thermal Efficiency

As mentioned earlier, Kirton houses may not meet modern standards for thermal efficiency. The concrete walls can be poor insulators, leading to higher heating costs and potential issues with condensation. Retrofitting these homes with modern insulation can be challenging and may require significant investment.

Maintenance and Repair

Regular Inspections

Regular inspections are essential to identify and address any issues with the Kirton house. This includes checking the condition of the concrete, timber elements, and ventilation cavities. A qualified surveyor can provide a detailed assessment and recommend any necessary repairs.

Concrete Repairs

If the concrete shows signs of carbonation or corrosion, it may be necessary to carry out repairs. This can involve removing the affected concrete, treating the steel reinforcement, and applying a new layer of concrete. Specialist contractors with experience in reinforced concrete repairs should carry out these repairs.

Moisture Management

Managing moisture is crucial to maintaining the condition of the Kirton house. This includes ensuring that the ventilation cavities and air inlet/outlet holes are clear and functioning correctly. Installing a modern damp-proof course (DPC) can also help to prevent moisture ingress.

Timber Treatment

Treating the timber elements with preservatives can help to protect against rot and insect damage. Regular inspections and maintenance are essential to ensure that the timber remains in good condition.

Insulation Upgrades

Upgrading the insulation in a Kirton house can improve thermal efficiency and reduce heating costs. This can involve installing internal or external insulation, as well as upgrading the windows and doors. A qualified contractor with experience in retrofitting older properties should carry out these upgrades.

Conclusion

The Kirton house is a unique and historically significant property type that offers both opportunities and challenges for home buyers and investors. Understanding the typical characteristics, potential hazards, and common defects of these homes is essential to making an informed decision. Regular inspections and maintenance are crucial to preserving the condition of the property and ensuring its long-term durability.

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.