Introduction to Stonecrete Houses

Stonecrete houses, a unique and historically significant type of property, have piqued the interest of home buyers and investors alike. These properties, constructed primarily in the mid-20th century, offer a distinctive architectural style and construction method that sets them apart from other residential buildings. As an expert surveyor with extensive knowledge of system-built properties, I will delve into the intricacies of Stonecrete houses, providing a detailed overview of their construction, typical characteristics, potential hazards, and inspection tips.

Historical Context and Manufacturing Details

Period and Location

Stonecrete houses were predominantly built from 1934 onwards, during a period when the UK was exploring various innovative construction methods to address housing shortages. These properties are typically found in urban and suburban areas across the UK, often forming part of larger housing estates developed during the mid-20th century.

Manufacturers and Designers

The British Cast Concrete Federation was the primary manufacturer of Stonecrete houses, with F J Moore Ltd serving as the designers. This collaboration resulted in a distinctive property type that combined practicality with a unique aesthetic.

Number Built and Alternative Names

While the exact number of Stonecrete houses built is not well-documented, they are known to be relatively common in certain regions. These properties are also referred to as F J Moore houses, named after the design firm responsible for their creation.

Identification Characteristics

Architectural Features

Stonecrete houses are typically two-storey terraced houses with a medium pitch hipped roof covered with tiles. The external walls are constructed using precast reinforced concrete (PRC) panels and posts, giving the properties a distinctive appearance.

Reference for Identification

For those looking to identify Stonecrete houses, the “Aid to Identification: Stonecrete Houses” (BRE OP 10, 1983) is a valuable resource. This document provides detailed information on the architectural and construction features of these properties.

Construction Details

Substructure

The substructure of Stonecrete houses consists of concrete strip footings, a damp-proof course (DPC), and precast concrete (PC) blocks. PRC base units are also used in the construction.

Frame

The main frame of Stonecrete houses is constructed using 7″ x 4″ storey height PRC posts, PRC corner posts, and a PC ring beam located on dowels protruding from the top of the lower columns. Additional components include PC first floor sills, L-shaped PC filler blocks between floor joists, and PC eaves level string units.

External Walls

The external walls are made up of storey height PC panels that fit into grooves formed in the posts. These panels are reinforced with plaster slabs fixed to the posts by T-headed screws.

Separating Wall and Partitions

The separating wall between properties is a 4″ clinker PC cavity wall, while internal partitions are constructed using 3″ or 4″ plaster blocks.

Floors

The ground floor of Stonecrete houses is typically timber, while the first floor consists of timber boarding on timber joists.

Roof

The roof structure includes timber rafters, purlins, and tiles, providing a traditional appearance that complements the overall design of the property.

Typical Characteristics and Hazards

Designated Defective

Stonecrete houses are classified as defective under the Defective Premises Act. This designation is due to the potential for structural issues related to the use of PRC in their construction. It is important for potential buyers and investors to be aware of this classification and the associated risks.

Common Defects

Corrosion of Steel Reinforcement

One of the most significant issues with Stonecrete houses is the corrosion of steel reinforcement within the PRC panels. This can lead to structural instability and requires careful inspection and maintenance.

Carbonation of Concrete

Carbonation, a process where carbon dioxide penetrates the concrete and reduces its alkalinity, can also affect the durability of Stonecrete houses. This issue is particularly relevant for the reinforced concrete components.

Cracking and Spalling

Cracking and spalling of the concrete panels are common defects in Stonecrete houses. These issues can compromise the structural integrity of the property and may require extensive repairs.

Inspection and Assessment Guidance

For those inspecting Stonecrete houses, several resources provide valuable guidance on assessing the durability of reinforced concrete. These include:

• “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)

Inspection Tips for Surveyors

Pre-Inspection Preparation

Before conducting an inspection of a Stonecrete house, it is essential to gather relevant information about the property, including its construction details, previous maintenance records, and any known issues. This preparation will help you focus on potential problem areas during the inspection.

External Inspection

Roof

Inspect the roof for any signs of damage or wear, such as missing or broken tiles, sagging, or water ingress. Pay particular attention to the timber rafters and purlins, as these components can be susceptible to rot and decay.

External Walls

Examine the external walls for signs of cracking, spalling, or other damage to the PRC panels. Look for any evidence of corrosion in the steel reinforcement, such as rust stains or exposed metal.

Internal Inspection

Ground and First Floors

Inspect the ground and first floors for any signs of structural movement, such as uneven or sagging floors. Check the timber joists and boarding for signs of rot, decay, or insect infestation.

Separating Wall and Partitions

Examine the separating wall and internal partitions for any signs of cracking or movement. Pay particular attention to the condition of the plaster blocks, as these can be prone to damage.

Additional Considerations

Damp and Moisture

Check for any signs of damp or moisture ingress, particularly around the DPC and PC blocks. Damp issues can lead to further structural problems and may require remedial work.

Carbonation Testing

Consider conducting carbonation testing on the concrete components to assess the extent of carbonation and its impact on the structural integrity of the property.

Maintenance and Repair Recommendations

Regular Inspections

Regular inspections are crucial for identifying and addressing potential issues in Stonecrete houses. Schedule inspections at least annually, and more frequently if any significant defects are identified.

Addressing Corrosion

If corrosion of the steel reinforcement is detected, it is essential to address this issue promptly. This may involve removing and replacing affected concrete panels, applying corrosion inhibitors, or using cathodic protection systems.

Repairing Cracks and Spalling

Cracks and spalling should be repaired as soon as they are identified to prevent further deterioration. This may involve patching the affected areas with suitable repair materials or replacing damaged panels.

Preventing Damp and Moisture Ingress

Ensure that the DPC and PC blocks are in good condition and functioning effectively to prevent damp and moisture ingress. Address any issues with the roof, gutters, and downpipes to prevent water from entering the property.

Conclusion

Stonecrete houses, with their unique construction and historical significance, offer a distinctive option for home buyers and investors. However, it is essential to be aware of the potential hazards and defects associated with these properties. By conducting thorough inspections and addressing any issues promptly, you can ensure the long-term durability and safety of a Stonecrete house.

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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