Historical Context and Background
The Malthouse house, a distinctive property type in the UK, was manufactured by W Malthouse Ltd and designed by the Sheffield City Architect. These properties were constructed primarily in the 1940s and 1950s, a period marked by a significant demand for housing post-World War II. With only 50 units built, these houses are relatively rare, making them a unique find for home buyers and investors.
These properties are typically found in urban areas, particularly in regions where rapid housing development was necessary to accommodate the growing population. The Malthouse house is also known by alternative names, but its unique construction and design features make it easily identifiable.
Identification Characteristics
Exterior Features
Malthouse houses are 2-storey semi-detached properties. They often feature a medium pitch hipped roof covered with asbestos cement tiles or a flat roof covered with bituminous felt. The external walls are constructed of brick or dense Precast Reinforced Concrete (PRC) panels, with visible junctions between adjacent panels.
The door and window frames are surrounded by PRC, and there is typically a PRC canopy over the front door. For houses with hipped roofs, the eaves height includes a rectangular flat-roofed bay containing the front door.
Interior Features
Internally, these houses have a variety of construction elements that are characteristic of the period. The ground and first floors are made of Reinforced Concrete (RC) topped hollow clay blocks and RC beams. The ceilings are rendered with foamed slag, and the staircase is constructed from PRC units with cork treads and oak nosings.
Construction Details
Substructure
The substructure of Malthouse houses consists of concrete strip footings with a 2-course blue brick Damp Proof Course (DPC). This foundation type was common in the mid-20th century and provides a stable base for the structure.
External Walls
The external walls are lightly reinforced brick cavity walls lined with 2 inches of rendered foamed slag concrete or 1/2 inch of cork grooved and keyed to the concrete. The PRC surrounds to door and window frames, along with wall ties, are notable features. In some variants, the external walls and separating walls are made entirely of dense PRC panels.
Separating Wall
The separating wall between semi-detached units is a brick cavity wall, providing both structural support and sound insulation between properties.
Partitions
Internal partitions are typically made of hollow clay blocks, although some variants use woodwool slabs or 3-inch foamed slag concrete panels.
Floors
Both the ground and first floors are constructed using RC topped hollow clay blocks and RC beams, with the ends toothed to fit recesses formed in the external walls. This method provides a robust and durable flooring system.
Ceilings
Ceilings in Malthouse houses are rendered with 3/4 inch foamed slag, a material that was commonly used for its insulating properties.
Roof
The roof construction varies between RC slabs covered with bituminous felt and RSA trusses with asbestos cement tiles. The choice of roofing material impacts the maintenance and potential hazards associated with the property.
Typical Hazards and Risks
Movement at Junctions Between PRC Panels
One of the most common issues with Malthouse houses is movement at the junctions between PRC panels. This movement can lead to cracks and gaps, which may compromise the structural integrity of the property and allow water ingress.
Corrosion of Light Reinforcement in PRC Panels
The light reinforcement within the PRC panels is susceptible to corrosion, particularly in areas exposed to moisture. This corrosion can weaken the panels and lead to structural issues over time.
High Rates of Carbonation in Dense PRC Panels
Dense PRC panels in Malthouse houses are prone to high rates of carbonation. This chemical process reduces the alkalinity of the concrete, making the reinforcement more susceptible to corrosion. Regular inspections and maintenance are essential to mitigate this risk.
Defective Premises Act Considerations
Malthouse houses are not typically classified as defective under the Defective Premises Act. However, the specific construction issues associated with PRC panels, such as movement at junctions and corrosion, require careful consideration. Buyers and investors should ensure that any potential property has been thoroughly inspected and that any necessary repairs or reinforcements have been carried out.
Inspection Guide for Surveyors
When inspecting a Malthouse house, surveyors should pay close attention to the following areas:
External Walls
- Check for visible movement at the junctions between PRC panels.
- Inspect for signs of corrosion in the light reinforcement within the panels.
- Assess the condition of the wall ties and PRC surrounds to door and window frames.
Roof
- Examine the condition of the asbestos cement tiles or bituminous felt covering.
- Look for signs of water ingress or damage to the RC slabs or RSA trusses.
Floors
- Inspect the RC topped hollow clay blocks and RC beams for signs of wear or damage.
- Ensure that the ends of the beams are securely fitted into the recesses formed in the external walls.
Ceilings
- Check the condition of the foamed slag render for any signs of cracking or deterioration.
Staircase
- Assess the condition of the PRC units, cork treads, and oak nosings for any signs of wear or damage.
Typical Defects Common in Malthouse Houses
Cracking and Movement
Cracking and movement at the junctions between PRC panels are common issues in Malthouse houses. These defects can compromise the structural integrity of the property and should be addressed promptly.
Corrosion of Reinforcement
Corrosion of the light reinforcement within PRC panels is another typical defect. This issue can weaken the panels and lead to structural problems if not properly managed.
Carbonation of Concrete
High rates of carbonation in dense PRC panels can reduce the alkalinity of the concrete, making the reinforcement more susceptible to corrosion. Regular inspections and maintenance are essential to mitigate this risk.
Water Ingress
Water ingress can occur through cracks and gaps in the PRC panels, as well as through the roof covering. This issue can lead to dampness and mould growth, which can affect the health and safety of the occupants.
Maintenance and Repair Considerations
Regular Inspections
Regular inspections are crucial for identifying and addressing potential issues in Malthouse houses. Surveyors should conduct thorough assessments of the external walls, roof, floors, ceilings, and staircase to ensure that any defects are promptly addressed.
Reinforcement Repairs
Corrosion of the light reinforcement within PRC panels can be addressed through various repair methods, including the application of corrosion inhibitors, cathodic protection, or the replacement of affected panels.
Carbonation Mitigation
To mitigate the effects of carbonation, surveyors can recommend the application of protective coatings or the use of carbonation-resistant materials in any repair work.
Waterproofing
Ensuring that the roof covering is in good condition and addressing any cracks or gaps in the PRC panels can help prevent water ingress. Waterproofing measures, such as the application of sealants or the installation of additional drainage systems, can also be beneficial.
Investment Potential
Despite the potential issues associated with Malthouse houses, these properties can offer significant investment potential. Their unique construction and historical significance make them attractive to certain buyers, and with proper maintenance and repair, they can provide a stable and valuable asset.
Historical Significance
The historical significance of Malthouse houses, as part of the post-World War II housing boom, adds to their appeal. Investors who appreciate the architectural and historical value of these properties may find them particularly attractive.
Rarity
With only 50 units built, Malthouse houses are relatively rare. This rarity can increase their value, particularly in areas where demand for unique and historically significant properties is high.
Potential for Modernisation
Malthouse houses offer significant potential for modernisation and improvement. Investors can enhance the value of these properties by addressing any structural issues, updating the interior, and incorporating modern amenities.
Conclusion
The Malthouse house is a unique and historically significant property type in the UK. Manufactured by W Malthouse Ltd and designed by the Sheffield City Architect, these houses were constructed in the 1940s and 1950s to meet the post-war housing demand. With only 50 units built, they are relatively rare and offer significant investment potential.
However, buyers and investors should be aware of the typical hazards and risks associated with these properties, including movement at junctions between PRC panels, corrosion of light reinforcement, and high rates of carbonation in dense PRC panels. Regular inspections and maintenance are essential to ensure the structural integrity and safety of these houses.
At Flettons, we’re committed to safeguarding your investment. When considering a property purchase, trust our seasoned expertise to uncover any hidden risks. For a thorough building survey, get your instant quote through our online calculator or call us directly on 0330 043 4650. Your home’s safety is our top priority. Disclaimer: This article is provided for general educational purposes only and is based on industry research, professional knowledge, and experience. It does not relate to any specific property and should not be relied upon when making a purchasing decision. Prospective purchasers should always commission an independent RICS-qualified surveyor to conduct a full inspection and provide a report on the actual condition of any property of interest.
