Introduction to the MeTraCon House

The MeTraCon house, a product of the post-war construction boom, stands as a testament to the innovative yet challenging era of system-built properties in the UK. Manufactured by Selleck, Nicholls & Williams Ltd between 1964 and 1979, these homes were designed to address the urgent housing needs of the time. With only 40 units built, the MeTraCon house is a rare find in today’s property market, making it a unique investment opportunity. However, potential buyers and investors must be well-informed about the characteristics, construction, and potential risks associated with these properties.

Historical Context and Manufacturing Details

Manufacturers and Designers

The MeTraCon house was both manufactured and designed by Selleck, Nicholls & Williams Ltd, a company known for its contributions to the system-built housing sector during the mid-20th century. The firm aimed to provide affordable and quickly constructed housing solutions in response to the post-war housing crisis. Their designs were innovative for the time, incorporating prefabricated components to expedite the construction process.

Period of Construction

The MeTraCon houses were constructed over a 15-year period from 1964 to 1979. This era was marked by a significant demand for housing, leading to the adoption of various system-built methods to meet the needs of the growing population.

Number and Types Built

Only 40 MeTraCon houses were built, making them relatively rare. These properties include bungalows and two- and three-storey houses, each with distinct architectural features that set them apart from other system-built homes of the time.

Identification Characteristics

Architectural Features

The MeTraCon house can be identified by several key characteristics:

• Roof: Shallow pitch gable roof covered with concrete tiles.
• External Walls: Front and rear external walls consist of storey-height exposed aggregate precast concrete (PC) panels infilled with timber frame panels up to the first-floor level, with horizontal timber boarding above. The gable walls follow a similar pattern.
• Construction Variants: While there are no known variants of the MeTraCon house, the system was also used for flats, which may exhibit similar construction features.

Common Locations

These houses are typically found in suburban areas where rapid development was necessary to accommodate the post-war population boom. They are often situated in estates that were developed during the 1960s and 1970s.

Construction Details

Substructure

The specific details of the substructure for MeTraCon houses are not well-documented. However, it is likely that they follow the common practices of the time, which may include concrete foundations.

External Walls

The external walls are a defining feature of the MeTraCon house:

• Front and Rear Walls: Storey-height exposed aggregate PC panels infilled with storey-height timber frame panels up to the first-floor level, with horizontal timber boarding above.
• Gable Walls: Similar to the front and rear walls, with storey-height exposed aggregate PC panels up to the first-floor level and horizontal timber boarding above.

Separating Walls

The separating walls are constructed using a timber frame cavity wall backed with insulation and lined with plasterboard. This design provides some degree of thermal and acoustic insulation between adjoining properties.

Internal Partitions

Internal partitions are made using Paramount partitions, which consist of a timber stud frame lined with plasterboard. The spine wall, which runs through the centre of the house, is also constructed using a timber stud frame lined with plasterboard.

Floors

• Ground Floor: Typically constructed from concrete, providing a solid and durable base.
• Upper Floors: Made from timber, which is a common practice in system-built homes of this era.

Ceilings

Ceilings are lined with plasterboard, a standard material used in many homes for its ease of installation and finish.

Roof

The roof structure consists of timber trusses covered with concrete tiles. This combination provides a robust and weather-resistant covering for the house.

Typical Defects and Risks

Structural Concerns

One of the primary concerns with MeTraCon houses is the potential for structural issues, particularly related to the use of precast concrete panels and timber frames. Over time, these materials can deteriorate, leading to problems such as:

• Corrosion of Steel Reinforcement: The steel reinforcement within the concrete panels can corrode, especially if the concrete has been exposed to moisture. This can compromise the structural integrity of the panels.
• Timber Frame Deterioration: Timber frames can be susceptible to rot and insect infestation, particularly if they have been exposed to damp conditions.

Thermal and Acoustic Insulation

While the timber frame cavity walls provide some degree of insulation, they may not meet modern standards for thermal and acoustic performance. This can result in higher energy bills and less effective soundproofing between rooms and adjoining properties.

Carbonation of Concrete

Carbonation is a process where carbon dioxide from the air penetrates the concrete and reacts with the calcium hydroxide to form calcium carbonate. This can reduce the alkalinity of the concrete, leading to corrosion of the steel reinforcement. The depth of carbonation can be assessed using guidance from BRE Digest 444 and BR 19.

Maintenance and Repair

Maintaining and repairing MeTraCon houses can be challenging due to the unique construction methods and materials used. Common maintenance issues include:

• Repairing Concrete Panels: Cracks and spalling in the concrete panels need to be addressed promptly to prevent further deterioration.
• Timber Frame Repairs: Any signs of rot or insect damage in the timber frames should be treated and repaired to maintain the structural integrity of the house.

Inspection and Assessment Guide

Pre-Inspection Preparation

Before conducting an inspection of a MeTraCon house, it is essential to gather as much information as possible about the property, including any previous surveys or maintenance records. This will help identify any known issues and areas that require particular attention.

External Inspection

• Roof: Check the condition of the concrete tiles and timber trusses. Look for any signs of damage or wear, such as missing or cracked tiles.
• Walls: Inspect the exposed aggregate PC panels for cracks, spalling, or signs of corrosion. Check the timber boarding for rot, warping, or insect damage.
• Gable Walls: Similar to the front and rear walls, inspect the gable walls for any signs of deterioration.

Internal Inspection

• Separating Walls: Check for any signs of dampness or mould, which could indicate issues with the insulation or timber frame.
• Partitions: Inspect the Paramount partitions for any signs of damage or wear. Ensure that the plasterboard is in good condition and securely attached.
• Floors: Check the condition of the concrete ground floor and timber upper floors. Look for any signs of movement, sagging, or damage.
• Ceilings: Inspect the plasterboard ceilings for cracks, stains, or signs of water damage.

Specialist Assessments

In some cases, it may be necessary to conduct specialist assessments to evaluate the condition of the concrete and timber components. This can include:

• Concrete Testing: Assessing the depth of carbonation and the condition of the steel reinforcement using techniques such as core sampling and chemical analysis.
• Timber Inspection: Using moisture meters and boroscopes to check for signs of rot or insect infestation within the timber frames.

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 MeTraCon house is not specifically listed as defective under this Act, the unique construction methods and materials used can present challenges in meeting modern standards.

Potential Legal Implications

If a MeTraCon house is found to have significant defects that affect its habitability or safety, there may be legal implications for the builder or developer. It is essential for buyers and investors to be aware of these potential risks and to seek professional advice if necessary.

Ensuring Compliance

To ensure compliance with the Defective Premises Act, it is crucial to conduct thorough inspections and assessments of the property. Any identified defects should be addressed promptly, and appropriate maintenance and repair work should be carried out to maintain the property’s condition.

Conclusion

The MeTraCon house represents a unique and intriguing chapter in the history of UK housing. While these properties offer a distinctive architectural style and historical significance, they also come with potential risks and challenges. By understanding the construction methods, typical defects, and maintenance requirements, buyers and investors can make informed decisions and ensure the long-term viability of their 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.

---