Historical Context and Manufacturing Background

The Alderton House, a notable example of post-war British architecture, was designed and manufactured by J S Alderton & Co. during the 1940s. This period was marked by a significant housing shortage in the UK, prompting the need for rapid and cost-effective construction methods. The Alderton House emerged as a solution, embodying the principles of system-built properties that were prevalent during this era.

These houses were primarily constructed in suburban areas, catering to the growing demand for family homes. The design and construction techniques employed in the Alderton House reflect the ingenuity and resourcefulness of the time, making it a subject of interest for both home buyers and property investors today.

Identifying Characteristics

The Alderton House is typically a two-storey detached property, easily recognizable by its flat roof covered with bituminous felt and its rendered external walls. These houses were built with reinforced concrete (RC) as the primary material, a choice driven by the need for durability and cost-efficiency.

Key Features

• Flat Roof: Covered with bituminous felt, providing a distinctive appearance and practical weatherproofing.
• Rendered External Walls: The walls are rendered throughout, offering a uniform and aesthetically pleasing finish.
• Reinforced Concrete Construction: Utilized for both structural integrity and longevity.

Construction Details

Understanding the construction details of the Alderton House is crucial for potential buyers and investors. This knowledge not only aids in identifying the property but also in assessing its condition and potential risks.

Substructure

The substructure of the Alderton House consists of RC piles and a 6-inch RC slab, thickened to 12 inches below the external and spine walls. A damp-proof course (DPC) is also included to prevent moisture ingress.

External Walls

The external walls are constructed from 8-inch dense aggregate RC cavity walls, with a 2-inch cavity filled with wheat straw rope laid horizontally. This unique insulation method was innovative for its time, providing both thermal and acoustic benefits. The walls are reinforced with 3/8-inch horizontal reinforcement and 1/4-inch hook reinforcement at junctions with internal walls.

Partitions

The spine wall, reaching eaves height, is made of 4-inch dense aggregate RC walls. Ground floor partitions are of storey height, also constructed from 4-inch dense aggregate RC walls. Non-loadbearing walls consist of 3-foot by 1-foot by 3-inch precast reinforced concrete (PRC) slabs.

Floors

• Ground Floor: Made of concrete, providing a solid and durable base.
• First Floor: Comprises tongue and groove (T&G) boarding on timber fillets cast into a 3-inch RC topping, reinforced with 5/8-inch mild steel (MS) bars and 1/4-inch MS bars on 5-inch hollow clay blocks.

Roof

The roof structure includes an 11-inch by 5 1/2-inch RC beam bearing on the spine wall, with 5-inch hollow clay blocks and an RC topping covered with bituminous felt.

Typical Hazards and Risks

While the Alderton House boasts a robust construction, it is not without its potential hazards and risks. Understanding these can help buyers and investors make informed decisions.

Reinforced Concrete Durability

Reinforced concrete, while durable, is susceptible to certain issues over time. The primary concerns include:

• Corrosion of Steel Reinforcement: Over time, the steel reinforcement within the concrete can corrode, leading to structural weaknesses. This is particularly prevalent in areas with high moisture levels or where the concrete cover is insufficient.
• Carbonation: This chemical process reduces the pH of the concrete, making the steel reinforcement more susceptible to corrosion. Regular inspections and maintenance are essential to mitigate this risk.

Bituminous Felt Roof

The flat roof covered with bituminous felt, while effective in its time, can present several challenges:

• Water Ingress: Over time, the bituminous felt can deteriorate, leading to potential water ingress and associated damage.
• Thermal Insulation: Flat roofs are generally less effective at providing thermal insulation compared to pitched roofs, potentially leading to higher energy costs.

Wheat Straw Rope Insulation

The use of wheat straw rope as cavity insulation, while innovative, can pose certain risks:

• Moisture Retention: Organic materials like wheat straw can retain moisture, potentially leading to mould growth and associated health risks.
• Pest Infestation: The organic nature of the insulation can attract pests, necessitating regular inspections and potential treatments.

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 Alderton House was a product of its time, it is essential to assess whether it meets modern standards.

Structural Integrity

Given the age of the Alderton House, a thorough structural assessment is crucial. This includes evaluating the condition of the reinforced concrete, the effectiveness of the damp-proof course, and the overall stability of the property.

Health and Safety

Ensuring that the property is free from health and safety hazards is paramount. This includes addressing any issues related to moisture ingress, mould growth, and pest infestations.

Inspection Guide for Surveyors

For surveyors tasked with inspecting an Alderton House, a systematic approach is essential. The following guide provides a step-by-step process to ensure a comprehensive assessment.

Pre-Inspection Preparation

• Review Historical Data: Familiarize yourself with the property’s history, including any previous inspections, repairs, or modifications.
• Gather Tools and Equipment: Ensure you have all necessary tools, including moisture meters, thermal imaging cameras, and concrete testing equipment.

External Inspection

• Roof: Inspect the bituminous felt for signs of wear, damage, or water ingress. Check the condition of the RC beams and hollow clay blocks.
• Walls: Examine the rendered external walls for cracks, spalling, or other signs of deterioration. Assess the condition of the wheat straw rope insulation and check for moisture retention or pest infestations.
• Substructure: Evaluate the condition of the RC piles and slab. Check for any signs of settlement or movement.

Internal Inspection

• Partitions: Inspect the spine wall and ground floor partitions for structural integrity. Look for any signs of cracking or movement.
• Floors: Assess the condition of the ground and first floors. Check for any signs of moisture ingress, warping, or other damage.
• Ceilings: While the specific construction details of the ceilings are not known, inspect for any signs of water damage, mould growth, or structural issues.

Reinforced Concrete Assessment

• Corrosion: Use a cover meter to assess the depth of the concrete cover and identify areas where the steel reinforcement may be at risk of corrosion.
• Carbonation: Conduct carbonation tests to determine the depth of carbonation and assess the risk to the steel reinforcement.
• Structural Integrity: Evaluate the overall condition of the reinforced concrete, looking for signs of spalling, cracking, or other structural issues.

Reporting and Recommendations

• Document Findings: Provide a detailed report of your findings, including photographs and measurements.
• Recommendations: Offer clear and actionable recommendations for any necessary repairs or maintenance. Highlight any urgent issues that require immediate attention.

Typical Defects and Maintenance Tips

Understanding the typical defects associated with the Alderton House can help homeowners and investors plan for maintenance and repairs.

Common Defects

• Concrete Spalling: This occurs when the surface of the concrete flakes off, exposing the steel reinforcement to the elements. Regular inspections and timely repairs can prevent further deterioration.
• Roof Leaks: The bituminous felt roof is prone to wear and tear, leading to potential leaks. Regular inspections and maintenance can help identify and address issues before they become severe.
• Moisture Ingress: The use of wheat straw rope insulation can lead to moisture retention, increasing the risk of mould growth and structural damage. Ensuring proper ventilation and addressing any signs of moisture ingress promptly is essential.

Maintenance Tips

• Regular Inspections: Conduct regular inspections of the roof, walls, and substructure to identify and address any issues early.
• Moisture Control: Ensure proper ventilation and address any signs of moisture ingress promptly to prevent mould growth and structural damage.
• Concrete Repairs: Address any signs of concrete spalling or cracking promptly to prevent further deterioration and ensure the structural integrity of the property.

Conclusion

The Alderton House, with its unique construction and historical significance, offers a fascinating glimpse into post-war British architecture. For home buyers and investors, understanding the intricacies of this property type is essential for making informed decisions. From its reinforced concrete construction to its innovative insulation methods, the Alderton House presents both opportunities and challenges.

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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