Overview of the AMcK House

The AMcK house, a distinctive property type in the UK, was manufactured by Cementation Co. Ltd and designed by Boyd Auger. These properties were constructed during the 1960s, with a total of 310 units built. Known for their unique construction and design, AMcK houses are primarily found in urban areas, often as part of larger housing estates. This article delves into the various aspects of AMcK houses, including their construction, typical characteristics, potential hazards, and inspection tips for prospective buyers and investors.

Historical Context and Manufacturing Details

Period of Construction

The AMcK houses were built in the 1960s, a period marked by a significant demand for affordable housing in the UK. This era saw the rise of various system-built properties designed to address the housing shortage quickly and efficiently.

Manufacturer and Designer

The AMcK houses were manufactured by Cementation Co. Ltd, a company known for its innovative construction techniques. The design was spearheaded by Boyd Auger, an architect who played a crucial role in the development of system-built housing during this period.

Number Built

A total of 310 AMcK houses were constructed, making them a relatively rare property type. Their unique design and construction methods have made them a subject of interest for both home buyers and property investors.

Identification Characteristics

Structural Features

AMcK houses are typically two-storey terraced houses. They are easily identifiable by their flat roofs covered with bituminous felt. The front and rear external walls are made of horizontal plastics-coated plywood weatherboarding, while the flank walls are constructed entirely of brick.

External Appearance

The use of horizontal plastics-coated plywood weatherboarding gives AMcK houses a distinctive look. This material was chosen for its durability and ease of maintenance. The brick flank walls provide additional structural support and fire resistance.

References and Certifications

The construction and design of AMcK houses are documented in various references, including the CIBSA 1968 and the NBA Certificate from January 1968. These references provide valuable information for surveyors and property inspectors.

Typical Construction Details

Substructure

The substructure of AMcK houses consists of a concrete foundation incorporating a ground floor slab. A damp-proof membrane (DPM) and damp-proof course (DPC) are included to prevent moisture ingress.

External Walls

The front and rear walls are constructed using timber frame panels sheathed internally and externally with plywood. These walls are clad with horizontal Tedlar-faced plywood weatherboarding and lined with foil-backed plasterboard. Glass fibre insulation is placed between the frame studs to enhance thermal performance. Additional features include Tedlar-coated aluminium flashing, galvanised mild steel fixing brackets, and PRC beams.

The flank walls are made of brick with a cavity filled with polystyrene insulation and a bitumen coating. Eaves height is achieved using 7″ PC panels on 3/4″ levelled bolts and dry pack mortar. Non-ferrous wall ties and galvanised mild steel firestops at the first-floor level are also present.

Separating Walls

Separating walls in AMcK houses consist of 7″ PRC eaves height panels with shear keys at vertical joints, secured with 3/4″ bolts and dry-pack mortar. An RC roof beam provides additional support.

Partitions

Internal partitions are proprietary, designed to provide flexibility in room layout and ease of installation.

Floors

The ground floor is made of concrete, while the first floor consists of stressed skin floor panels fixed to the flank wall panels with 1/2″ bolts.

Ceilings

Ceilings are constructed using plasterboard, providing a smooth and durable finish.

Roof

The roof is made of stressed skin timber roof panels fixed to RC roof beams and covered with bituminous felt. Glass fibre insulation is installed at ceiling level to improve thermal efficiency.

Typical Hazards and Risks

Structural Issues

One of the primary concerns with AMcK houses is the potential for structural issues, particularly related to the timber frame and plywood components. Over time, these materials can deteriorate, leading to problems such as rot, warping, and loss of structural integrity.

Moisture Ingress

The flat roof design, while aesthetically pleasing, can be prone to water ingress if not properly maintained. Bituminous felt roofing requires regular inspection and maintenance to prevent leaks and water damage.

Insulation and Thermal Performance

While the original design includes glass fibre insulation, the thermal performance of AMcK houses may not meet modern standards. Upgrading insulation and improving airtightness can be necessary to enhance energy efficiency and reduce heating costs.

Fire Safety

The use of timber and plywood in the construction of AMcK houses raises concerns about fire safety. Ensuring that firestops and other fire-resistant features are in good condition is crucial for occupant safety.

Defective Premises Act Considerations

Classification as Defective

AMcK houses are not specifically classified as defective under the Defective Premises Act. However, their age and construction methods mean that they may require careful inspection and maintenance to ensure they meet current safety and performance standards.

Legal Implications

Under the Defective Premises Act, property owners and landlords have a duty to ensure that their properties are safe and fit for habitation. This includes addressing any structural issues, moisture ingress, and fire safety concerns that may be present in AMcK houses.

Inspection Tips for Surveyors

External Inspection

When inspecting an AMcK house, start with a thorough external inspection. Look for signs of deterioration in the plywood weatherboarding, such as warping, cracking, or rot. Check the condition of the bituminous felt roofing and ensure that it is free from leaks and damage.

Internal Inspection

Inside the property, pay close attention to the condition of the timber frame and plywood panels. Look for signs of moisture ingress, such as damp patches, mould, or mildew. Check the insulation and ensure that it is in good condition and providing adequate thermal performance.

Structural Integrity

Assess the overall structural integrity of the property, paying particular attention to the condition of the PRC beams, RC roof beams, and other load-bearing components. Look for any signs of movement, cracking, or other structural issues.

Fire Safety

Ensure that all fire safety features, such as firestops and non-ferrous wall ties, are in place and in good condition. Check that the property meets current fire safety regulations and consider recommending upgrades if necessary.

Typical Defects and Maintenance

Common Defects

Some of the most common defects found in AMcK houses include:

• Rot and Decay: Timber components, particularly in the external walls and roof, can be prone to rot and decay if exposed to moisture.
• Warping and Cracking: Plywood panels can warp or crack over time, compromising the structural integrity and appearance of the property.
• Moisture Ingress: Flat roofs and inadequate waterproofing can lead to moisture ingress, causing damage to the internal structure and finishes.
• Insulation Issues: Original insulation may be insufficient by modern standards, leading to poor thermal performance and higher energy costs.

Maintenance Tips

To maintain an AMcK house in good condition, consider the following maintenance tips:

• Regular Inspections: Conduct regular inspections of the roof, external walls, and internal structure to identify and address any issues early.
• Roof Maintenance: Ensure that the bituminous felt roofing is in good condition and free from leaks. Consider upgrading to a more durable roofing material if necessary.
• Moisture Control: Address any signs of moisture ingress promptly to prevent further damage. This may include repairing or replacing damaged weatherboarding, improving waterproofing, and upgrading insulation.
• Structural Repairs: Address any structural issues, such as rot, warping, or cracking, promptly to maintain the integrity of the property. This may involve replacing damaged timber components or reinforcing load-bearing elements.

Variants and Alternative Cladding Materials

Variants

While the standard AMcK house features horizontal plastics-coated plywood weatherboarding, some variants may have different cladding materials. These variants can offer different aesthetic and performance characteristics, but the underlying construction principles remain the same.

Alternative Cladding Materials

Alternative cladding materials that may be used in AMcK house variants include:

• Brick: Some variants may feature brick cladding, providing a more traditional appearance and improved durability.
• Render: Rendered finishes can offer a smooth, modern look and additional weather protection.
• Metal Cladding: Metal cladding, such as aluminium or steel, can provide a contemporary appearance and enhanced durability.

Conclusion

The AMcK house is a unique and historically significant property type in the UK, offering both opportunities and challenges for home buyers and investors. Understanding the construction details, typical characteristics, and potential hazards of these properties is essential for making informed decisions. Regular maintenance and careful inspection can help ensure that AMcK houses remain safe, comfortable, and valuable investments.

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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