Published on 10th July 2017
The clock is ticking for coastal homes
Do cavity wall ties mean anything to you? Probably not right, but if you own a brick building with a cavity you probably have quite a lot of them tying your walls together. "So what's the problem you may ask", the answer is "rusting" cavity wall ties and the effects this can have on your building.
It is estimated that all brick buildings containing cavity walls constructed before the 2000s will have a degree of wall tie corrosion.
Wall ties corrode at different rates and hence why not every building is at immediate risk. However, it's worth noting that if your building is within a marine environment (within 10km from water), then your building will be at a higher risk from rusting wall ties.
What to look out for:
Bowing, leaning or bulging walls.
Weak mortar joints.
If rendered; rust marks on the surface.
What problems do rusting wall ties cause to buildings?
As a very common building method here in Australia, cavity walls play an important role in keeping us comfortable and safe from the elements outside by creating a cushion of air between inside and outside of your home. The cushion of air in the cavity helps maintain and control room temperature and humidity by acting as a buffer.
To create this cushion of air, walls must be built separately and allow for 50mm to 70mm cavity between the internal wall and external wall. Each wall is 110mm wide, and they are tied together with a wall tie which takes the overall width of a cavity wall to 270mm to 290mm and at this width, the wall is very sturdy.
However, as the building ages, the ties connecting the walls rust and snap. The process of wall ties rusting and snapping allows internal walls and external walls to uncouple and become freestanding. As freestanding walls are only 110mm wide, they are very unstable and collapse is a possibility.
A noticeable sign that your walls have rusting ties is leaning or outward bulging, which are signs of lateral movement.
A rusted wall tie discovered by a Buildfix engineer in an apartment block in Sydney's Eastern Suburbs.
How can I better manage my building and prevent wall ties from rusting?
Unfortunately, there is little you can do to prevent wall ties corroding in older buildings as the steel used to make wall ties have few anti-corrosive properties and access is limited.
However, Buildfix has a solution that will allow the existing rusting wall ties to remain in the wall while introducing a new wall tie to the structure without removing a single brick.
Our HelicalBar™ remedial wall tie system is quick, clean and cost-effective.
Rusting wall ties may be affecting your home
Your home may require a remedial wall tie solution.
Call Buildfix on 1300 854 115 or book a FREE inspection today.
* If you reside in NSW, ACT or southern QLD.