Overview of the Smith House
The Smith House, a hallmark of post-war British architecture, stands as a testament to the ingenuity and resilience of the mid-20th century construction industry. Manufactured by Smith’s Building Systems and designed by a team of innovative architects, these properties were built between 1945 and 1955. With approximately 4,500 units constructed, the Smith House, also known as British Steel Construction (BSC), remains a significant part of the UK’s housing landscape.
Identifying Characteristics
Architectural Features
Smith Houses are typically two-storey semi-detached or terraced homes. They are easily identifiable by their medium pitch hipped or gable roofs, which are covered with concrete tiles. The external walls are either brick-slip-faced panels or rendered throughout, giving them a distinctive appearance. Additionally, these houses feature Precast Reinforced Concrete (PRC) window surrounds and sill units, which are characteristic of the era’s construction methods.
Common Locations
These properties are predominantly found in suburban areas across the UK, particularly in regions that experienced significant housing shortages post-World War II. They were designed to provide affordable and durable housing solutions for the growing population during that period.
Construction Details
Substructure
The foundation of a Smith House consists of a concrete slab thickened to form strip foundations under the external walls. This robust foundation was designed to provide stability and support for the structure above.
External Walls
The external walls are constructed using 1 1/4″ brick slip facing attached to 2′ 6″ x 7′ x 8″ foamed slag PRC panels on the ground floor and 6″ panels on the first floor. The panels are joined using concrete grout or mortar in grooved horizontal and vertical joints, secured with mild steel staples. Dense reinforced concrete lintels are used over openings to provide additional support.
Separating Walls and Partitions
The separating walls between properties are made of 8″ foamed slag PRC panels, while internal partitions are constructed using 4″ foamed slag concrete. This design ensures both structural integrity and sound insulation between rooms and neighbouring properties.
Floors
The ground floor consists of timber block flooring on a 2″ foamed slag screed laid over a concrete base. The first floor features timber boarding on timber joists, supported by the ground floor PRC panels and brick noggins.
Roof
The roof structure comprises timber rafters and purlins, covered with concrete tiles. Some variants of the Smith House may feature roofs with light steel trusses, grooved lightweight precast concrete decking, and tiles.
Typical Defects and Hazards
Foundation Movement
One of the most common issues with Smith Houses is foundation movement. This can lead to structural instability and requires careful monitoring and potential remedial work to ensure the safety and longevity of the property.
Cracking
Cracking is another prevalent issue, particularly at the junctions between PRC panels and at the junctions of external walls, partitions, and separating walls. These cracks can compromise the structural integrity of the property and may require professional assessment and repair.
Deterioration of PRC Window and Sill Units
Over time, the PRC window surrounds and sill units can deteriorate, leading to potential water ingress and further structural issues. Regular inspection and maintenance are essential to address these problems promptly.
Designation as Defective
Under the Defective Premises Act, Smith Houses are designated as defective due to the inherent issues with PRC construction. This designation means that buyers and investors need to be aware of the potential risks and necessary remedial works when considering these properties.
Inspection Guide for Surveyors
External Inspection
- Foundation and Ground Movement: Check for signs of foundation movement, such as uneven floors, cracks in the walls, and doors or windows that do not close properly.
- Cracking: Inspect the external walls for cracks, particularly at the junctions between PRC panels and at the junctions of external walls, partitions, and separating walls.
- PRC Window and Sill Units: Examine the condition of the PRC window surrounds and sill units for signs of deterioration, such as spalling concrete or rusting reinforcement.
Internal Inspection
- Internal Walls and Partitions: Check for cracks in the internal walls and partitions, particularly at the junctions with external walls and separating walls.
- Floors: Inspect the ground and first floors for signs of movement or instability, such as uneven surfaces or creaking floorboards.
- Ceilings: Although the ceiling construction details are not well-documented, check for any signs of sagging or water damage that could indicate underlying issues.
Roof Inspection
- Roof Structure: Examine the roof structure, including the timber rafters and purlins, for signs of rot, insect infestation, or other damage.
- Roof Covering: Check the condition of the concrete tiles for any signs of damage or wear, and ensure that the roof is watertight.
Variants and Their Implications
Light Steel Trusses and Precast Concrete Decking
Some Smith Houses feature roofs with light steel trusses and grooved lightweight precast concrete decking. These variants may have different maintenance requirements and potential issues compared to the standard timber roof structure.
Rendered External Walls
In some cases, the external walls of Smith Houses are rendered rather than brick-slip-faced. Rendered walls can be more susceptible to cracking and water ingress, so it is essential to inspect the condition of the render and address any issues promptly.
Maintenance and Remedial Works
Addressing Foundation Movement
If foundation movement is detected, it is crucial to engage a structural engineer to assess the extent of the movement and recommend appropriate remedial works. This may include underpinning the foundations or other stabilisation methods.
Repairing Cracks
Cracks in the walls should be repaired promptly to prevent further deterioration. This may involve filling the cracks with suitable materials and, in some cases, reinforcing the affected areas to restore structural integrity.
Replacing Deteriorated PRC Units
Deteriorated PRC window surrounds and sill units should be replaced to prevent water ingress and further structural issues. This may involve removing the damaged units and installing new, more durable replacements.
Conclusion
The Smith House, with its distinctive architectural features and historical significance, remains a notable part of the UK’s housing stock. However, potential buyers and investors must be aware of the typical defects and hazards associated with these properties. By conducting thorough inspections and addressing any issues promptly, it is possible to maintain the structural integrity and value of a Smith House.
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.
