Garstang Surveyor Case Study: Wall Tie Failure in a Semi-Detached House in Garstang
Introduction
This case study details the discovery and implications of wall tie failure in a semi-detached house located in Garstang. As an RICS (Royal Institution of Chartered Surveyors) accredited surveyor, my objective is to provide a thorough explanation of the issue to assist potential homebuyers in making an informed decision.
Garstang Surveyor – Property Overview
The property under consideration was a semi-detached house, built in the 1960s, situated in a quiet residential area of Garstang. The house exhibited typical architectural features of the period, including cavity wall construction, which were a common building practice at the time.
Identification of the Problem
During a routine Level 3 Building Survey, several symptoms indicative of wall tie failure were observed:
1. Horizontal Cracks: Horizontal cracking was noted on the external brickwork, particularly around the middle courses of the walls. These cracks are often a sign that the wall ties, which are designed to secure the outer brickwork to the inner structure, have corroded and expanded, causing the bricks to crack and displace.
2. Bulging Walls: Localised bulging of the external walls was observed. This distortion occurs because the corroded wall ties lose their strength and fail to hold the walls together properly, leading to an outward bulge under the pressure of the building’s weight.
3. Internal Cracks: Cracks were also visible on the internal plasterwork, correlating with the external defects. These cracks typically appear around window and door frames, indicating movement and instability in the wall structure.
Cause of the Problem
Wall ties are metal strips or wires embedded in the mortar joints during construction to tie the inner and outer leaves of cavity walls together. Over time, particularly in properties of this age, the steel wall ties can corrode due to exposure to moisture and salts within the cavity. As they rust, they expand, causing the surrounding masonry to crack and eventually leading to a loss of structural integrity.
Implications for the Property
Wall tie failure can have significant structural implications if not addressed promptly:
1. Structural Integrity: The primary concern is the weakening of the wall structure. If the ties fail completely, there is a risk of wall collapse, particularly under heavy loads or during high winds.
2. Aesthetic Damage: The visible cracking and bulging can detract from the property’s appearance and may lower its market value.
3. Water Ingress: Cracks in the external brickwork can allow water to penetrate the cavity, leading to damp issues inside the property, which can cause further damage and potential health problems due to mould growth.
Garstang Surveyor – Recommended Remedial Action
Addressing wall tie failure involves several steps:
1. Inspection and Assessment: A detailed inspection by a specialist should be conducted to assess the extent of the wall tie corrosion and to map out the exact locations of failure.
2. Replacement of Wall Ties: The existing corroded wall ties need to be replaced with new stainless steel ties, which are resistant to corrosion. This process involves removing small sections of mortar, inserting the new ties, and repointing the mortar joints.
3. Repair of Masonry: Cracked and displaced bricks should be carefully removed and replaced, and all cracks should be properly repaired to restore the structural integrity and appearance of the walls.
4. Preventative Measures: To prevent future issues, consideration should be given to improving the cavity wall insulation and ensuring proper drainage and moisture management around the property.
Conclusion
While the discovery of wall tie failure in this semi-detached house in Garstang is concerning, it is a common issue in properties of this age and construction type. With proper remediation, the structural integrity and appearance of the property can be fully restored. Potential homebuyers should factor in the cost of these repairs when considering the purchase but can be reassured that once addressed, the property can offer many years of safe and stable living.
I recommended engaging a specialist contractor to carry out the necessary repairs to the highest standard, ensuring peace of mind and protecting the investment in this particular home.
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Disclaimer: The information contained in this blog is provided for general guidance only and does not constitute legal, financial, medical, or other professional advice. No warranty, express or implied, is given as to the accuracy or completeness of the information. Reliance on any information provided is at your own risk.
