Understanding the IBIS House

The IBIS house, a notable example of system-built properties, emerged in the 1960s as a response to the post-war housing shortage in the UK. These homes, manufactured by Richard Thomas & Baldwins and the Pressed Steel Co., were designed by A Gordon & Partners. Known for their distinctive construction and design, IBIS houses are found in various configurations, including bungalows and two-storey detached, semi-detached, and terraced houses. This article delves into the essential aspects of IBIS houses, providing valuable insights for home buyers and investors.

Historical Context and Manufacturing

Period and Location

IBIS houses were predominantly built during the 1960s, a period marked by a significant demand for affordable and quickly constructed housing. These properties are typically located in suburban areas across the UK, where rapid urban development was necessary to accommodate the growing population.

Manufacturers and Designers

The primary manufacturers of IBIS houses were Richard Thomas & Baldwins and the Pressed Steel Co. These companies collaborated with A Gordon & Partners, the designers responsible for the architectural and structural aspects of the IBIS house. Their combined expertise resulted in a unique housing solution that addressed the immediate needs of the time.

Characteristics of IBIS Houses

Design and Structure

IBIS houses are easily identifiable by their distinctive design features. They often have monopitch or flat roofs covered with butyl rubber sheets. The external walls are aggregate-coated up to the first-floor level, with vertically profiled steel sheets above. Corners are typically masked with cover strips, giving the houses a clean and uniform appearance. Some IBIS houses also feature single-storey or two-storey extensions, adding to their versatility.

Construction Details

Substructure

The substructure of an IBIS house consists of concrete pads below stanchions, providing a stable foundation. A concrete oversite and a pre-cast (PC) apron around the perimeter further enhance the structural integrity. A damp-proof course (DPC) is included to prevent moisture ingress.

Frame

The main frame of an IBIS house is constructed using hollow box stanchions, perimeter beams, floor and ceiling support beams, and intermediate joists. These components are typically galvanised or coated with RTB for added protection against corrosion.

External Walls

The external walls are made of storey-height pre-cast frame panels clad with steel and backed with polystyrene sheets. The lower part of the walls is aggregate-coated, while the upper part features vertically profiled steel sheets. Internally, the walls are lined with plasterboard.

Internal Partitions

Internal partitions in IBIS houses are constructed using pre-cast frame panels lined with plasterboard, providing a lightweight yet sturdy solution for dividing spaces.

Floors

The ground and first floors are made of plywood sheets supported by steel joists, ensuring a robust and durable flooring system.

Ceilings and Roof

Ceilings are lined with plasterboard, while the roof consists of plywood sheets covered with a single piece of butyl rubber. The roof covering is fixed around the edges and weighted down with pebbles to prevent movement.

Typical Hazards and Risks

Structural Issues

One of the primary concerns with IBIS houses is the potential for structural issues, particularly related to the steel frame. Over time, corrosion can weaken the structural integrity, leading to significant safety hazards. Regular inspections and maintenance are crucial to identify and address any signs of deterioration.

Thermal Insulation

The original design of IBIS houses included polystyrene sheets for thermal insulation. However, these materials may not meet modern energy efficiency standards. Upgrading the insulation can improve the property’s energy performance and reduce heating costs.

Moisture Ingress

Despite the inclusion of a damp-proof course, moisture ingress can still be a concern, particularly if the DPC has deteriorated over time. Regular inspections and repairs are necessary to prevent damp-related issues, such as mould growth and structural damage.

Fire Safety

The use of polystyrene sheets in the construction of IBIS houses raises concerns about fire safety. Polystyrene is highly flammable, and its presence can increase the risk of fire spread. Upgrading to fire-resistant materials can enhance the safety of the property.

Defective Premises Act and IBIS Houses

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 IBIS houses were innovative at the time of their construction, some may now be considered defective under this Act due to issues such as structural deterioration, inadequate insulation, and fire safety concerns. It is essential for buyers and investors to conduct thorough inspections and seek professional advice to ensure compliance with current standards.

Inspection and Assessment of IBIS Houses

Pre-Inspection Preparation

Before conducting an inspection of an IBIS 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 identify potential problem areas and ensure a comprehensive assessment.

External Inspection

Roof

Inspect the roof for signs of damage or wear, such as cracks, leaks, or missing pebbles. Check the butyl rubber covering for any signs of deterioration and ensure that it is securely fixed around the edges.

Walls

Examine the external walls for signs of corrosion, particularly in the steel cladding. Look for cracks, bulges, or other indications of structural issues. Check the condition of the aggregate coating and the vertically profiled steel sheets.

Foundation

Inspect the foundation for any signs of movement or cracking. Ensure that the concrete pads and oversite are in good condition and that the damp-proof course is intact.

Internal Inspection

Frame

Check the condition of the steel frame, looking for signs of corrosion or damage. Pay particular attention to the stanchions, perimeter beams, and support beams.

Floors

Inspect the floors for any signs of sagging, warping, or damage. Check the condition of the plywood sheets and the steel joists.

Walls and Partitions

Examine the internal walls and partitions for signs of damage, such as cracks or bulges. Check the condition of the plasterboard lining and look for any signs of moisture ingress.

Ceilings

Inspect the ceilings for any signs of damage or sagging. Check the condition of the plasterboard and ensure that it is securely fixed.

Additional Considerations

Thermal Insulation

Assess the thermal insulation of the property and consider upgrading if necessary. Modern insulation materials can significantly improve energy efficiency and reduce heating costs.

Fire Safety

Evaluate the fire safety of the property, particularly the presence of polystyrene sheets. Consider upgrading to fire-resistant materials to enhance safety.

Typical Defects in IBIS Houses

Corrosion

Corrosion of the steel frame is one of the most common defects in IBIS houses. Regular inspections and maintenance are essential to identify and address any signs of corrosion before they compromise the structural integrity of the property.

Moisture Ingress

Moisture ingress can lead to a range of issues, including mould growth, structural damage, and health concerns. Regular inspections and repairs are necessary to prevent and address moisture-related problems.

Insulation

The original insulation materials used in IBIS houses may not meet modern standards. Upgrading the insulation can improve energy efficiency and reduce heating costs.

Fire Safety

The presence of polystyrene sheets raises concerns about fire safety. Upgrading to fire-resistant materials can enhance the safety of the property.

Maintaining and Improving IBIS Houses

Regular Inspections

Regular inspections are crucial to identify and address any issues before they become significant problems. A professional surveyor can provide a comprehensive assessment of the property and recommend necessary repairs and upgrades.

Structural Repairs

Addressing structural issues, such as corrosion and damage to the steel frame, is essential to maintain the safety and integrity of the property. Professional repairs and maintenance can extend the lifespan of the property and ensure compliance with current standards.

Insulation Upgrades

Upgrading the insulation can significantly improve the energy efficiency of the property. Modern insulation materials can reduce heating costs and enhance the comfort of the home.

Fire Safety Improvements

Enhancing the fire safety of the property is crucial, particularly if polystyrene sheets are present. Upgrading to fire-resistant materials can reduce the risk of fire spread and improve the overall safety of the property.

Conclusion

IBIS houses, with their distinctive design and construction, represent an important chapter in the history of UK housing. While they offered a practical solution to the post-war housing shortage, modern buyers and investors must be aware of the potential issues and necessary upgrades to ensure these properties meet current standards. Regular inspections, professional maintenance, and targeted improvements can help maintain the safety, comfort, and value of IBIS houses.

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.

---