Overview of the Arrowhead House

The Arrowhead house, also known by its alternative names such as Prowting, RFC, and Rigid Frame Construction, is a distinctive property type that emerged in the UK during the mid-20th century. Manufactured by Rigid Frame Construction Ltd and designed by a team of innovative architects, these properties were built between 1963 and 1970. With approximately 1,000 units constructed, the Arrowhead house remains a notable example of system-built properties from that era.

These homes are typically found in suburban areas and are characterized by their unique construction methods and materials. They come in various forms, including bungalows, two-storey semi-detached houses, and terraced houses. The Arrowhead house is known for its shallow pitch gable or monopitch roof, front and rear walls of brick or exposed aggregate, and distinctive flat canopy over the front door.

Historical Context and Manufacturers

The Arrowhead house was a product of its time, designed to address the post-war housing shortage in the UK. Rigid Frame Construction Ltd, the manufacturer, played a pivotal role in the development and production of these homes. The company was known for its innovative use of materials and construction techniques, which allowed for rapid and cost-effective building.

During the 1960s, there was a significant demand for affordable housing, and system-built properties like the Arrowhead house provided a solution. These homes were designed to be quickly assembled on-site, using prefabricated components. This approach not only reduced construction time but also minimized costs, making homeownership more accessible to a broader population.

Typical Characteristics of the Arrowhead House

Exterior Features

The Arrowhead house is easily identifiable by its exterior features. The roof is either a shallow pitch gable or monopitch, covered with interlocking concrete tiles or bituminous felt. The front and rear walls are constructed from brick, exposed aggregate, or Tyrolean finish PC panels. In some cases, mathematical tiling is used up to the eaves level at the separating wall, with flat asbestos cement sheets or horizontal timber boarding above.

The gable wall is typically made of brick or mathematical tiling, which is returned around corners or to the eaves level with flat asbestos cement sheets at the apex. A flat canopy over the front door is a common feature, providing a distinctive look to the property.

Interior Features

Inside, the Arrowhead house features a concrete ground floor and a first floor made of tongue-and-groove boarding on timber joists. The ceilings are plasterboard, and the roof structure consists of timber rafters, bituminous felt, timber battens, and interlocking concrete tiles.

The internal walls are made of composite panels of compressed fibre and flat asbestos cement sheets. The separating wall between properties is also constructed from storey-height composite panels, providing sound insulation and fire resistance.

Typical Hazards and Risks

Asbestos

One of the primary concerns with Arrowhead houses is the presence of asbestos. Asbestos cement sheets were commonly used in the construction of these properties, particularly in the external walls and roof. Asbestos is a hazardous material that can pose serious health risks if disturbed. It is essential to have a professional survey conducted to identify and manage any asbestos-containing materials in the property.

Structural Issues

Over time, Arrowhead houses may develop structural issues, particularly with the metal web stanchions used in the frame. Superficial corrosion of these stanchions is a common problem, which can compromise the structural integrity of the property. Regular inspections and maintenance are crucial to address any corrosion and prevent further deterioration.

Roof and Wall Defects

The roof and walls of Arrowhead houses can also be prone to defects. Broken or missing tiles in the tile hanging, poorly constructed blockwork at the verge of the gable wall in the roof space, and large notches cut in floor joists are some of the typical issues that may arise. These defects can lead to water ingress, dampness, and other related problems if not addressed promptly.

Defective Premises Act and Arrowhead Houses

The Defective Premises Act 1972 is a piece of legislation in the UK that imposes a duty on builders, developers, and landlords to ensure that properties are constructed and maintained to a reasonable standard. While the Arrowhead house is not specifically listed as a defective property under this act, the presence of asbestos and potential structural issues mean that it is essential to conduct thorough inspections and maintenance.

Homebuyers and investors should be aware of their rights and responsibilities under the Defective Premises Act. If a property is found to be defective, the owner may be entitled to compensation for any necessary repairs or remedial work. It is advisable to seek legal advice if you believe that an Arrowhead house you own or are considering purchasing may be affected by defects.

Inspecting an Arrowhead House: A Step-by-Step Guide

Pre-Inspection Preparation

Before conducting an inspection of an Arrowhead house, it is essential to gather as much information as possible about the property. This includes reviewing any available documentation, such as previous survey reports, maintenance records, and planning permissions. It is also helpful to familiarize yourself with the typical characteristics and potential issues associated with Arrowhead houses.

External Inspection

Roof

Begin the inspection by examining the roof. Look for any signs of damage or wear, such as broken or missing tiles, sagging, or water stains. Pay particular attention to the condition of the bituminous felt and interlocking concrete tiles. Check the gutters and downpipes for blockages or leaks, as these can lead to water damage.

Walls

Inspect the front, rear, and gable walls for any signs of cracking, bulging, or dampness. Check the condition of the brickwork, exposed aggregate, or Tyrolean finish PC panels. Look for any areas where the mathematical tiling, asbestos cement sheets, or horizontal timber boarding may be damaged or deteriorating.

Canopy

Examine the flat canopy over the front door for any signs of damage or wear. Ensure that it is securely attached and free from any structural issues.

Internal Inspection

Ground Floor

Inspect the concrete ground floor for any signs of cracking, settlement, or dampness. Check for any large notches cut in the floor joists, as these can weaken the structure and lead to further issues.

First Floor

Examine the tongue-and-groove boarding on the first floor for any signs of damage or wear. Check the timber joists for any signs of rot, insect infestation, or structural issues.

Ceilings

Inspect the plasterboard ceilings for any signs of cracking, sagging, or water stains. Pay particular attention to areas around light fixtures and vents, as these can be prone to leaks.

Internal Walls

Examine the composite panels of compressed fibre and flat asbestos cement sheets for any signs of damage or wear. Check for any areas where the panels may be loose or deteriorating.

Structural Elements

Metal Web Stanchions

Inspect the metal web stanchions for any signs of superficial corrosion. Pay particular attention to areas where the stanchions are exposed to moisture, as these are more prone to corrosion. Ensure that any corrosion is addressed promptly to prevent further deterioration.

Frame

Examine the frame for any signs of structural issues, such as sagging, cracking, or movement. Check the condition of the protective coating, such as stove enamelled paint, and ensure that it is intact and free from damage.

Asbestos

Conduct a thorough inspection for any asbestos-containing materials in the property. This includes the external walls, roof, and internal partitions. If asbestos is identified, it is essential to have it managed or removed by a qualified professional to ensure the safety of the occupants.

Typical Construction of Arrowhead Houses

Substructure

The substructure of Arrowhead houses consists of concrete pads below the stanchions and a concrete slab thickened around the perimeter. A damp-proof course (DPC) is installed to prevent moisture from rising through the structure.

Frame

The frame is made up of four double PS metal web stanchions, one single-storey RS hollow box stanchion, eight PS metal web perimeter beams, one flitched floor support beam, and two PS metal web purlins. The frame is protected with a stove enamelled paint coating to prevent corrosion.

External Walls

The external walls are constructed from storey-height timber frame infill panels clad with mathematical tiling over bituminous felt at the separating wall and asbestos cement sheets to the first floor level. The upper sections of the walls are clad with tile hanging over bituminous felt and asbestos cement sheets. The gable wall is clad with brickwork and/or mathematical tiling over bituminous felt to the eaves level, with angle trims masking the corners.

Internal Walls

The internal walls are made of composite panels of compressed fibre and flat asbestos cement sheets. The separating wall between properties is constructed from storey-height composite panels, providing sound insulation and fire resistance.

Floors

The ground floor is made of concrete, while the first floor consists of tongue-and-groove boarding on timber joists. In some variants, the ground floor may be suspended, with chipboard on timber joists.

Roof

The roof structure consists of timber rafters, bituminous felt, timber battens, and interlocking concrete tiles. In some cases, the roof may be flat, with timber boarding and bituminous felt.

Typical Defects in Arrowhead Houses

Superficial Corrosion of Metal Web Stanchions

One of the most common defects in Arrowhead houses is the superficial corrosion of the metal web stanchions. This can compromise the structural integrity of the property if not addressed promptly. Regular inspections and maintenance are essential to prevent further deterioration.

Broken or Missing Tiles

Broken or missing tiles in the tile hanging are another common issue. This can lead to water ingress and dampness, which can cause further damage to the property. It is important to replace any damaged or missing tiles as soon as possible to prevent water damage.

Large Notches in Floor Joists

Large notches cut in the floor joists can weaken the structure and lead to further issues. It is important to inspect the floor joists regularly and address any notches or damage promptly.

Poorly Constructed Blockwork

Poorly constructed blockwork at the verge of the gable wall in the roof space is another common defect. This can lead to structural issues and water ingress if not addressed. Regular inspections and maintenance are essential to ensure the integrity of the blockwork.

Variants of Arrowhead Houses

Arrowhead houses come in various variants, each with its own unique features and construction methods. Some of the common variants include:

Concrete Trench Fill Foundation

Some Arrowhead houses have a concrete trench fill foundation with a concrete or brick kerb around the perimeter. This provides additional stability and support to the structure.

Additional Stanchions

In some cases, additional stanchions are used to support wide spans. This provides additional structural support and stability to the property.

Conventional Crosswall Construction

Some Arrowhead houses feature conventional crosswall construction with PS metal web beams at the first floor and eaves level in the front and rear walls. This provides additional structural support and stability.

Brick and Block Cavity External Walls

In some variants, the external walls are constructed from brick and block cavity walls lined with plasterboard. This provides additional insulation and soundproofing.

Gable Apex of Asbestos Cement Sheets

Some Arrowhead houses have a gable apex made of asbestos cement sheets. This provides additional weatherproofing and durability.

PC Exposed Aggregate Cladding Panels

In some cases, the external walls are clad with PC exposed aggregate cladding panels. This provides a distinctive look and additional weatherproofing.

PC Lightweight Panels with Tyrolean Finish

Some Arrowhead houses feature PC lightweight panels with a Tyrolean finish. This provides a distinctive look and additional weatherproofing.

Linings of Straw Cored Panels

In some variants, the internal walls are lined with straw cored panels. This provides additional insulation and soundproofing.

Block Cavity Separating Wall

Some Arrowhead houses have a block cavity separating wall lined with plasterboard. This provides additional soundproofing and fire resistance.

Honeycomb Plasterboard Partitions

In some cases, the internal partitions are made of honeycomb plasterboard. This provides additional insulation and soundproofing.

Suspended Ground Floor

Some Arrowhead houses feature a suspended ground floor made of chipboard on timber joists. This provides additional insulation and soundproofing.

Timber Roof Trusses

In some variants, the roof structure consists of timber roof trusses. This provides additional structural support and stability.

Flat Roof

Some Arrowhead houses have a flat roof made of timber boarding and bituminous felt. This provides additional weatherproofing and durability.

Conclusion

The Arrowhead house is a distinctive and historically significant property type in the UK. Manufactured by Rigid Frame Construction Ltd between 1963 and 1970, these homes are known for their unique construction methods and materials. While they offer many benefits, such as rapid construction and cost-effectiveness, they also come with potential hazards and risks, particularly related to asbestos and structural issues.

When considering the purchase of an Arrowhead house, it is essential to conduct a thorough inspection and be aware of the typical defects and maintenance requirements. By understanding the unique characteristics and potential issues associated with these properties, homebuyers and investors can make informed decisions and ensure the long-term safety and stability of their 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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