Historical Context and Background

The Grenfell Baines house, a unique architectural marvel, stands as a testament to post-war ingenuity and the drive for rapid housing solutions. Designed by the Grenfell Baines Group and manufactured by English Electric Ltd, these properties were constructed in 1945, a period marked by a significant housing shortage in the UK. Only two of these semi-detached houses were built, making them rare and intriguing subjects for property enthusiasts and investors alike.

Design and Construction

Structural Overview

The Grenfell Baines house is a two-storey semi-detached property, identifiable by its medium pitch gable roof covered with bituminous felt. The front and rear external walls are composed of fine pebble-dashed ribbed steel sheets, while the gable wall is constructed of brick. A brick pier at the separating wall adds to the structural integrity of the building.

Substructure

The foundation of the Grenfell Baines house consists of concrete strip footings and a hollow clay block oversite. A bituminous felt damp-proof membrane (DPM) is used to prevent moisture ingress, and the ground floor is a concrete slab.

Frame

The frame of the house is a steel channel setting out jig, with front and rear elevations of eaves height pre-stressed concrete (PSC) panels. The structure includes rolled steel channel (RSC) perimeter beams and double rolled steel angle (RSA) forming T lattice first-floor joists. The roof panels are made of PSC framing, stiffened with pre-stressed (PS) cross members and incorporating mock roof trusses.

External Walls

The front and rear walls are made of vertically ribbed steel sheets, with a cavity filled with wood wool slabs for insulation. The gable wall is a cavity brick construction, providing additional stability and thermal efficiency.

Internal Partitions

Internal partitions are constructed from wood wool slabs, offering a lightweight yet sturdy solution for dividing internal spaces.

Floors and Ceilings

The ground floor is a solid concrete slab, while the first floor consists of plywood on timber bearers. Ceilings are made from wood wool slabs, contributing to the overall fire resistance and acoustic performance of the property.

Roof

The roof is constructed from fibreboard and bituminous felt, providing a durable and weather-resistant covering.

Typical Characteristics and Hazards

Identification Characteristics

Grenfell Baines houses are easily identifiable by their two-storey semi-detached design, medium pitch gable roof, and the distinctive fine pebble-dashed ribbed steel sheets on the front and rear external walls. The gable wall of brick and the brick pier at the separating wall further distinguish these properties.

Common Hazards and Risks

1. Corrosion of Steel Components: Over time, the steel frame and external steel sheets can suffer from corrosion, particularly if the protective coating has deteriorated.
2. Moisture Ingress: The bituminous felt DPM and roof covering can degrade, leading to potential moisture ingress and associated issues such as damp and mould.
3. Thermal Bridging: The steel frame can act as a thermal bridge, leading to heat loss and potential condensation issues.
4. Asbestos: Given the period of construction, there is a possibility that asbestos-containing materials were used, particularly in the insulation and roofing materials.

Defective Premises Act Considerations

The Grenfell Baines house is not specifically classed as defective under the Defective Premises Act. However, due to the potential for corrosion and other age-related issues, it is crucial to conduct a thorough survey to identify any defects that could impact the safety and habitability of the property.

Inspection Guide for Surveyors

Pre-Inspection Preparation

Before conducting an inspection, surveyors should familiarize themselves with the following references:
– Steel framed and steel clad houses: inspection and assessment (BR 113)
– Inspecting steel houses (IP 14/87)
– Maintaining and improving steel houses (IP 15/87)

External Inspection

1. Roof: Check the condition of the bituminous felt covering for signs of wear, tear, or damage. Inspect the fibreboard for any signs of water ingress or rot.
2. Walls: Examine the pebble-dashed ribbed steel sheets for corrosion, dents, or other damage. Check the brick gable wall for cracks or signs of movement.
3. Damp-Proof Membrane: Inspect the bituminous felt DPM for any signs of deterioration or breaches that could allow moisture ingress.

Internal Inspection

1. Frame: Assess the condition of the steel frame, looking for signs of corrosion or structural weakness. Pay particular attention to the junctions and connections.
2. Partitions: Check the wood wool slab partitions for any signs of damage or degradation.
3. Floors: Inspect the concrete ground floor for cracks or signs of settlement. Check the plywood first floor for any signs of deflection or damage.
4. Ceilings: Examine the wood wool slab ceilings for any signs of water damage or sagging.

Additional Considerations

1. Thermal Performance: Assess the insulation levels and look for any signs of thermal bridging that could lead to heat loss or condensation issues.
2. Asbestos: If there is any suspicion of asbestos-containing materials, recommend a specialist survey to confirm and, if necessary, arrange for safe removal.

Typical Defects and Maintenance

Common Defects

1. Corrosion: The steel frame and external steel sheets are prone to corrosion, particularly in areas where the protective coating has failed.
2. Moisture Ingress: Degradation of the bituminous felt DPM and roof covering can lead to moisture ingress, causing damp and mould issues.
3. Thermal Bridging: The steel frame can act as a thermal bridge, leading to heat loss and potential condensation issues.
4. Asbestos: Asbestos-containing materials may be present, particularly in the insulation and roofing materials.

Maintenance Tips

1. Regular Inspections: Conduct regular inspections to identify and address any signs of corrosion, moisture ingress, or other defects.
2. Protective Coatings: Ensure that the protective coatings on the steel components are maintained and reapplied as necessary to prevent corrosion.
3. Damp-Proof Membrane: Regularly check the condition of the bituminous felt DPM and roof covering, and repair or replace as necessary to prevent moisture ingress.
4. Thermal Insulation: Improve thermal insulation to reduce the risk of thermal bridging and associated condensation issues.
5. Asbestos Management: If asbestos-containing materials are present, ensure they are managed safely and, if necessary, arrange for their removal by a specialist.

Conclusion

The Grenfell Baines house, with its unique design and construction, offers a fascinating glimpse into post-war housing solutions. While these properties are rare, they present both opportunities and challenges for home buyers and investors. Understanding the typical characteristics, potential hazards, and maintenance requirements is crucial for making informed decisions and ensuring the long-term safety and habitability of these homes.

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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