Understanding Uniment Houses

Uniment houses, a unique type of system-built property, were constructed primarily in the 1940s by Uniment (France) Ltd. These properties are relatively rare, with only about 40 built, making them a niche but intriguing subject for home buyers and investors. Typically found in semi-detached and terraced forms, Uniment houses are characterized by their steep pitch gable roofs, rendered external walls, and distinctive architectural features such as cantilevered flat PC canopies over the front doors.

Historical Context and Manufacturers

Uniment houses emerged in the post-war era, a time when the UK faced a significant housing shortage. The need for rapid construction methods led to the development of various system-built properties, including those by Uniment (France) Ltd. These houses were designed to be both cost-effective and quick to assemble, utilizing pre-cast concrete (PC) components extensively.

Key Characteristics

• Period Built: 1940s
• Number Built: Approximately 40
• Designers: Uniment (France) Ltd
• Typical Locations: Predominantly found in urban and suburban areas across the UK
• Alternative Names: None widely recognized

Architectural Features

External Features

Uniment houses are easily identifiable by their steep pitch gable roofs covered with tiles. The external walls are rendered throughout, providing a uniform appearance. Some houses feature eaves height gable bays and dormer windows above the first floor level, adding to their distinctive look. The cantilevered flat PC canopies over the front doors are another hallmark of these properties.

Internal Features

Internally, Uniment houses typically have concrete ground floors and timber joists on the first floor. The walls are constructed using clinker PRC panel cavity walls, reinforced with ‘chicken mesh’ and/or mild steel (MS) bars. The roof structure comprises timber rafters and purlins, supporting the tiled roof.

Construction Details

Substructure

The substructure of Uniment houses consists of a concrete slab with a damp-proof course (DPC) to prevent moisture ingress. This forms a solid foundation for the rest of the structure.

External Walls

The external walls are constructed using 12″ square hollow PC columns with a V rebate to accommodate the ends of PC panels infilled with reinforced concrete (RC). These walls are rendered and consist of 15″ x 3′ 3″ x 1 1/4″ clinker PRC panel cavity walls, reinforced with ‘chicken mesh’ and/or 1/4″ MS bars. The cavity is filled with clinker aggregate concrete, providing additional strength and insulation.

Internal Walls and Partitions

The separating walls between properties are also made of clinker PRC panel cavity walls, filled with clinker aggregate concrete. Internal partitions are constructed using clinker concrete blocks, ensuring robust internal divisions.

Floors

The ground floor is typically a solid concrete slab, while the first floor comprises timber joists on MS joist hangers fixed into the external wall between the top of the first-floor eaves beam and the clinker PRC panel above. This provides a sturdy and reliable flooring system.

Roof

The roof structure consists of timber rafters and purlins, supporting the tiled roof. Some variants of Uniment houses feature flat roofed dormer windows to the first-floor bedrooms and wide fronted two-storey gable bays. In some cases, the first floor may be constructed using PC floor slabs, and the roof may utilize PC trusses.

Typical Defects and Hazards

Vertical Cracking of Render

One common issue with Uniment houses is vertical cracking of the render at the junction between PC columns and clinker PRC panels. This can be a sign of structural movement or settlement and may require professional assessment and repair.

Water Penetration

Water penetration through external walls is another typical problem. This can lead to damp issues internally, which can affect the structural integrity of the property and the health of its occupants. Ensuring that the external render is well-maintained and addressing any cracks or gaps promptly can help mitigate this risk.

Reinforcement Corrosion

The use of ‘chicken mesh’ and MS bars for reinforcement can lead to corrosion over time, especially if the concrete cover is insufficient or if the property is exposed to harsh environmental conditions. This can compromise the structural integrity of the walls and may require remedial work.

Timber Decay

The timber elements of the roof and first floor can be susceptible to decay, particularly if there are issues with water ingress or poor ventilation. Regular inspections and maintenance are essential to prevent and address any signs of timber decay.

Defective Premises Act Considerations

Uniment houses are not specifically listed under the Defective Premises Act. However, like any property, they must meet certain standards to ensure they are safe and habitable. If significant defects are identified, it may be necessary to undertake remedial works to bring the property up to standard.

Inspection Guide for Surveyors

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

External Inspection

• Render Condition: Check for vertical cracking, particularly at the junctions between PC columns and clinker PRC panels.
• Water Penetration: Look for signs of dampness or water ingress on the external walls.
• Roof Structure: Inspect the condition of the tiles, timber rafters, and purlins. Check for any signs of decay or damage.
• Canopies and Dormer Windows: Ensure that the cantilevered flat PC canopies and dormer windows are in good condition and securely fixed.

Internal Inspection

• Walls and Partitions: Examine the condition of the clinker PRC panel cavity walls and internal partitions. Look for any signs of cracking or movement.
• Floors: Check the condition of the concrete ground floor and timber joists on the first floor. Look for any signs of deflection or decay.
• Ceilings: Although the ceiling construction is not well-documented, inspect for any signs of sagging or damage.
• Roof Space: If accessible, inspect the roof space for signs of timber decay, water ingress, or inadequate ventilation.

Maintenance and Repair Tips

Render Repairs

To address vertical cracking of the render, it is essential to use a flexible, breathable render system that can accommodate movement without cracking. Regular maintenance and prompt repairs can help prevent further deterioration.

Damp Proofing

Ensuring that the DPC is intact and effective is crucial in preventing water penetration. If damp issues are identified, it may be necessary to install additional damp-proofing measures, such as a chemical DPC or tanking.

Reinforcement Protection

To protect the reinforcement from corrosion, it is important to maintain adequate concrete cover and address any signs of spalling or cracking promptly. In some cases, it may be necessary to apply a protective coating to the reinforcement.

Timber Treatment

Regular inspections and treatment of timber elements can help prevent decay. This may include applying preservative treatments, ensuring adequate ventilation, and addressing any sources of moisture.

Conclusion

Uniment houses, with their unique construction and historical significance, offer a fascinating opportunity for home buyers and investors. Understanding the typical characteristics, potential defects, and maintenance requirements of these properties is essential in making an informed decision. By conducting thorough inspections and addressing any issues promptly, you can ensure that a Uniment house remains a safe and valuable 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.

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