Historical Context and Manufacturing

The Winget house, a notable example of system-built properties, was constructed between 1928 and 1931. These homes were primarily built in the UK, with a total of approximately 4,700 units, including the Underdown variant. The design and manufacturing of these properties were spearheaded by Winget Ltd, with contributions from F Hill. These houses were part of a broader movement during the interwar period to address housing shortages through innovative construction techniques.

Identification Characteristics

Winget houses are typically two-storey semi-detached or terraced homes. They feature a medium pitch hipped roof covered with tiles and external walls that are rendered throughout. Some of these houses also have single-storey bay windows, adding to their distinctive appearance. These identification characteristics are crucial for surveyors and potential buyers to recognize Winget houses accurately.

Construction Details

Substructure

The substructure of Winget houses consists of concrete strip footings and under-building, with a damp-proof course (DPC) to prevent moisture ingress. This foundational setup is relatively robust, but it is essential to inspect for any signs of settlement or movement.

External Walls

The external walls are a complex assembly involving reinforced concrete (RC) columns and RC ring beams. The walls are rendered and consist of 9″ x 3′ x 3″ precast reinforced concrete (PRC) slabs, with a 2″ cavity filled with clinker concrete slabs. These slabs are shaped to act as permanent formwork for casting the columns, with the cavity closed by timber or building board strips. Galvanized mild steel (MS) ties are used to secure the structure, and corner columns are cast in hollow precast concrete (PC) blocks.

Separating Walls and Partitions

The separating walls between properties are constructed using PRC slabs and clinker concrete slab cavity walls. Internal partitions are made from clinker concrete panels, providing a sturdy yet lightweight solution for internal divisions.

Floors

The ground floor typically consists of timber boarding on timber joists, supported by a timber sole plate. The first floor follows a similar construction method, with timber boarding on timber floor joists, all supported by an RC ring beam. This combination of materials provides a balance of strength and flexibility.

Ceilings and Roof

Ceilings in Winget houses are generally made from plasterboard, offering a smooth and easily maintainable surface. The roof structure comprises timber rafters covered with tiles, providing a traditional and aesthetically pleasing finish.

Typical Defects and Hazards

Cracking of Render

One of the most common issues with Winget houses is the cracking of the external render. This can be due to various factors, including thermal movement, settlement, or poor initial application. Regular inspection and maintenance are essential to prevent water ingress and further deterioration.

Carbonation of Concrete and Corrosion of Reinforcement

Carbonation of concrete is a chemical process that reduces the alkalinity of concrete, leading to the corrosion of embedded steel reinforcement. This is a significant concern in Winget houses, particularly in the RC columns and ring beams. Regular monitoring and remedial work are necessary to address this issue.

Low Chloride Levels

While low chloride levels in concrete are generally beneficial, they can also indicate poor-quality concrete or inadequate mixing during construction. This can lead to reduced durability and increased susceptibility to other forms of degradation.

Poorly Cast Columns

Some Winget houses suffer from poorly cast columns, particularly at the bases where they do not meet the first-floor RC ring beams correctly. This can compromise the structural integrity of the property and requires careful inspection and potential reinforcement.

Designation as Defective

Winget houses are designated as defective under the Defective Premises Act. This designation means that these properties are recognized as having inherent structural issues that can affect their safety and habitability. Buyers and investors should be aware of this designation and consider the implications for insurance, mortgage availability, and potential repair costs.

Inspection Guide for Surveyors

External Inspection

1. Render Condition: Check for any signs of cracking, bulging, or detachment. Pay particular attention to areas around windows and doors, as these are common points of stress.
2. Carbonation and Corrosion: Look for signs of rust staining or spalling concrete, which can indicate corrosion of the reinforcement. Use a carbonation depth test to assess the extent of carbonation.
3. Column Integrity: Inspect the bases of RC columns for any signs of poor casting or separation from the first-floor ring beams. Check for vertical alignment and any signs of movement.

Internal Inspection

1. Flooring: Examine the timber boarding and joists for any signs of rot, insect infestation, or excessive deflection. Check the condition of the timber sole plate on the ground floor.
2. Partitions: Inspect clinker concrete panels for any signs of cracking or movement. Ensure that internal partitions are securely fixed and free from significant defects.
3. Ceilings: Look for any signs of sagging, cracking, or water damage in plasterboard ceilings. Check for adequate ventilation in roof spaces to prevent condensation and mould growth.

Roof Inspection

1. Rafters and Tiles: Inspect timber rafters for any signs of rot, insect damage, or warping. Check the condition of roof tiles and ensure they are securely fixed and free from damage.
2. Guttering and Downpipes: Ensure that guttering and downpipes are in good condition and free from blockages. Check for any signs of water ingress or damage to the external walls.

Variants and Regional Differences

England

In England, some Winget houses feature unreinforced columns, brick and galvanized steel strips in place of first-floor ring beams, and concrete ground floors. Hollow PRC block floors and double PC quoin blocks at corners are also common. Additionally, some properties have a brick outer leaf of external walls and brick partitions.

Scotland

In Scotland, Winget houses may have external wall panels of various widths, ranging from 9″ to 3′. Additional RC columns are often present at changes in wall direction, such as bay windows. External wall panels are typically dry bedded, and galvanized MS wall ties are nailed into slabs. Corner columns are usually 6″ x 6″ PC columns.

Maintenance and Repair Strategies

Render Repairs

To address cracking render, it is essential to remove any loose or damaged material and apply a suitable repair mortar. Ensure that the new render is compatible with the existing material and adequately bonded to the substrate. Regular repainting and sealing can help protect the render from further damage.

Concrete and Reinforcement

For carbonation and corrosion issues, it is crucial to remove any damaged concrete and treat the exposed reinforcement with a corrosion inhibitor. Apply a suitable repair mortar to restore the concrete cover and protect the reinforcement. Regular monitoring and maintenance are essential to prevent further deterioration.

Structural Reinforcement

In cases of poorly cast columns or other structural issues, it may be necessary to reinforce the affected areas. This can involve adding additional steel reinforcement, applying structural epoxy, or using other strengthening techniques. Consult a structural engineer to determine the most appropriate solution for each specific case.

Conclusion

Winget houses, with their unique construction methods and historical significance, present both opportunities and challenges for home buyers and investors. Understanding the typical characteristics, common defects, and necessary maintenance strategies is crucial for making informed decisions about these properties. Regular inspections and proactive repairs can help ensure the long-term safety and habitability of Winget 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.

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