The Smith House: A Comprehensive Guide for Home Buyers and Investors
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.
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It would be good to have a picture of an actual Smith House, not some generic illustration. What was the floor space of a Smith House? I guess they would have conformed to the Ministry’s standards in the 1940s, but the Smith houses in Leicester were built in 1954 when Macmillan had reduced space standards. You do not mention the method of construction which required a gantry.
Smith Houses, developed post-World War II, were a type of prefabricated housing in the UK, specifically designed to address the housing shortage. You are correct that the space standards were influenced by changing government policies, with the 1944 Dudley Committee setting earlier guidelines, but by 1954, when the Smith Houses in Leicester were built, the standards had been reduced under Harold Macmillan’s housing initiatives. These policies led to a focus on quantity over space, and the size of Smith Houses was notably smaller than their earlier counterparts.
Floor Space of a Smith House
The typical floor space for a Smith House built under these post-1951 reduced standards was around 850 to 1,000 square feet (approximately 79 to 93 square meters). This floor space varied depending on the number of bedrooms (usually two or three) and the layout. These homes were modest but aimed to provide sufficient space for a growing family, albeit with smaller room dimensions compared to homes built immediately after the war.
Construction Method
The construction of Smith Houses involved a steel frame, clad with prefabricated concrete panels. This process was part of a broader trend in the 1940s and 1950s toward system-built housing, where sections of the home were manufactured offsite and assembled onsite. The use of a gantry system in the construction process was a significant feature of Smith Houses. Gantries were essentially large, mobile cranes used to hoist and position the prefabricated panels into place. These panels were often heavy and large, requiring mechanical assistance for accurate placement.
In particular, the gantry system was crucial in speeding up the construction process, as it enabled rapid assembly of the house frame and cladding. Once the steel framework was erected, the concrete panels could be slotted into position, significantly reducing the time and labour required compared to traditional brick-and-mortar construction.
Ministry of Housing Standards and Reduction
When the first Smith Houses were developed, they likely adhered to the standards set by the Ministry of Housing in the 1940s. These earlier standards provided larger living spaces and rooms. However, as you mentioned, by the time the Leicester Smith Houses were built in 1954, Harold Macmillan’s policies had reduced space standards in a bid to meet the ambitious target of building 300,000 homes annually. This reduction in space resulted in smaller room dimensions and more compact overall layouts, but the homes still adhered to the essential functional and aesthetic requirements.
Typical Construction Characteristics of Smith Houses
Roof: The roof of a Smith House typically comprised a lightweight structure covered with tiles or sometimes asbestos sheeting. The lightweight nature of the roof was necessary due to the prefabricated design and the need for quick assembly.
Walls
: Smith Houses were characterised by their non-traditional walls made of prefabricated concrete panels. These panels were often reinforced with steel mesh for added structural integrity. The cladding system was designed to fit around the steel frame, and while this provided a fast construction method, it led to long-term durability issues due to poor insulation and water ingress.
Floors
: The floors were usually of a solid concrete construction at ground level, with timber joists supporting the upper floor in two-storey versions. Insulation was minimal, and over time, these concrete floors could suffer from cracks and moisture-related issues.
Typical Defects in Smith Houses
Concrete Spalling and Corrosion: One of the main issues with Smith Houses, particularly in later years, was concrete spalling—where the concrete panels begin to degrade, crack, and lose chunks of material. This is often caused by corrosion of the steel mesh reinforcement inside the panels, which expands as it rusts, leading to cracks in the surrounding concrete.
Poor Insulation
: Smith Houses were built before modern insulation standards were introduced, meaning they suffer from poor thermal performance. Many were cold and damp, with condensation problems exacerbated by the concrete construction, which does not breathe like traditional brick.
Water Ingress
: The panel construction was vulnerable to water ingress, particularly at the joints between panels. Over time, water penetration could lead to damp problems inside the house, contributing to mould growth and structural deterioration.
Foundation Movement
: Smith Houses, like many post-war prefabricated homes, were often built on simple, shallow foundations. This could lead to subsidence issues, particularly in areas with poor soil conditions.
Classification Under Defective Premises Act
Smith Houses, while not explicitly listed under the Housing Defects Act 1984, were considered substandard due to their construction type. Many fell into disrepair due to the typical defects mentioned above. However, under the Defective Premises Act, homeowners or occupiers could seek remedies if it was proven that their home posed a health and safety risk due to its defective construction. The main concerns with Smith Houses revolved around the degradation of the concrete panels and the structural issues arising from steel corrosion, making them liable under this legislation in some cases.
Notes for Surveyors
When surveying a Smith House, particular attention should be paid to:
Condition of concrete panels:
Check for visible signs of spalling, cracking, or reinforcement corrosion.
Insulation and dampness:
Inspect for condensation, poor insulation, and water ingress at the panel joints.
Roof structure:
Look for sagging, degradation of tiles, or problems related to lightweight construction.
Subsidence:
Check for evidence of foundation movement or settlement.
Surveyors assessing these homes for prospective buyers should inform them of the long-term maintenance costs and potential structural risks associated with these properties.