Wall ties are crucial components in the structural integrity of buildings, particularly those with cavity walls. These inconspicuous elements play a vital role in connecting the inner and outer layers of brickwork, ensuring stability and preventing wall collapse. However, wall ties can fail over time due to various factors, potentially leading to severe structural issues if left unaddressed.
Recognising the signs of failed wall ties is essential for maintaining the structural health of your building and preventing costly damage. This article will explore the key indicators that suggest your wall ties need repair, the causes of failure, and the steps necessary to rectify the problem. By understanding these signs and acting promptly, property owners can safeguard their buildings against the risks associated with compromised wall ties.
Common Causes of Wall Tie Failure
Wall tie failure can occur due to several factors:
- Corrosion of mild steel wall ties: This is the most common cause, particularly in older buildings where galvanised mild steel ties were used. Exposure to moisture within the cavity leads to rust, weakening the tie's structural integrity.
- Insufficient wall ties in original construction: Inadequate spacing or number of wall ties during initial construction can lead to premature failure, especially under high wind loads.
- Water ingress: Persistent moisture within the cavity can accelerate corrosion and compromise the effectiveness of wall ties, even in more resistant materials like stainless steel.
- Building movement and temperature fluctuations: Thermal expansion and contraction, as well as settlement or subsidence, can stress wall ties beyond their design limits, leading to failure over time.
Signs You Need to Repair Your Wall Ties
Visual Signs
- Horizontal cracks in brickwork coinciding with tie positions: These typically appear at regular intervals, often every 4-5 brick courses.
- Cracks around windows and doors: Wall tie failure can cause localised stress, leading to visible cracks near openings.
- Bulging or bowing of walls: As ties fail, walls may start to separate, resulting in noticeable outward bulging.
- Loose or detached brickwork: In severe cases, bricks may become loose or fall away from the wall.
Structural Signs
- Wall collapse or partial collapse: In extreme cases, entire sections of the outer leaf may fail.
- Doors and windows becoming misaligned: As the wall structure shifts, openings may become distorted.
- Increased noise from wind or weather: Failed wall ties allow more movement, resulting in audible creaking or whistling during windy conditions.
Other Indicators
- Age of the building: Properties built between the 1920s and 1980s are more likely to have used corrosion-prone mild steel ties.
- Previous repairs or signs of water damage: These can indicate ongoing issues with the wall structure and potential tie failure.
How to Identify Failed Wall Ties
- Using metal detectors: A quality metal detector can locate existing wall ties within the cavity. Scanning the wall surface will reveal the pattern and spacing of ties.
- Conducting a professional wall tie survey: This involves a thorough inspection by a qualified surveyor, often including the use of borescopes to visually assess the condition of ties within the cavity.
- Checking for rust stains or efflorescence: Rust stains on brickwork can indicate corroding ties. Efflorescence (white, powdery deposits) may suggest moisture issues within the cavity.
Steps to Replace Failed Wall Ties
Preparation:
- Identify the positions of existing wall ties using a metal detector.
- Clear the area around the ties, removing any obstructions.
Installation:
- Drill pilot holes for new ties, ensuring correct depth and angle.
- Install mechanical or resin wall ties:
- For mechanical ties: Insert the tie into the pilot hole and expand using a setting tool.
- For resin ties: Inject resin into the hole, then insert the tie and allow to cure.
Post-Installation:
- Ensure correct spacing and distribution of new ties (typically 2.5 ties per m² in a staggered pattern).
- Test the fixing strength of the ties using a pull-out tester.
Best Practices for Wall Tie Replacement
- Follow recommended spacing guidelines: Install ties at 450mm horizontal centres and 450mm vertical centres, staggered between courses.
- Use the right type of replacement ties: Choose ties suitable for the condition of the brickwork and the presence of cavity insulation.
- Apply external waterproofing treatments: This helps prevent future corrosion by reducing moisture ingress.
Preventative Measures
- Regular inspections: Conduct visual checks annually and professional surveys every 5-10 years.
- Address water ingress issues promptly: Repair damaged pointing, flashing, and guttering to prevent moisture accumulation in the cavity.
- Use high-quality, stainless steel wall ties: For new constructions or replacements, opt for austenitic stainless steel ties (grades 304 or 316) to ensure longevity and corrosion resistance.
Wall Tie Replacement FAQs
Here are the answers to your top questions on wall tie replacements:
- What are the most common signs of wall tie failure?
- Key indicators include horizontal cracks in brickwork, bulging or bowing walls, loose bricks, and misaligned doors or windows.
- How can I identify failed wall ties without professional help?
- Use a metal detector to locate existing ties, look for rust stains or efflorescence, and check for visible cracks or bulges in your walls.
- Is wall tie replacement a DIY job?
- While possible, it's not recommended. Professional expertise ensures correct installation and prevents further structural damage.
- What types of wall ties are best for replacement?
- The choice depends on your wall's condition and insulation. Stainless steel mechanical, resin, or neoprene ties are common options.
- How often should wall ties be inspected?
- Regular inspections are crucial, especially for buildings over 30 years old or in areas with harsh weather conditions.
- What are the risks of ignoring wall tie failure?
- Potential consequences include severe structural damage, wall collapse, and increased vulnerability to weather-related issues.
- How can I prevent future wall tie failure?
- Use high-quality stainless steel ties, address water ingress promptly, and apply external waterproofing treatments.
Contact our wall tie experts
Should you need help with wall tie replacements, our team is here to help! For advice or support, you can contact us at 01639 790426 or 07852 229017 or by filling in our online contact form.
We work throughout South Wales, Swansea, Cardiff, Bristol, and nearby areas.
