Sometimes known as ‘brick ties’, wall ties are an essential part of cavity wall building. They provide an additional support to ensure the entire structure is safe and stable. Although they are hidden from view once the wall has been completed, wall ties have become standard practice in the UK since the early 20th century. Therefore, it is highly probable that the walls that make up your home are laden with these strong, metal ties throughout.
What are they?
Wall ties are strips or bars of metal that span the entire cavity of your wall. They are ordinarily used to join the two parts of a cavity wall together, allowing them to act as one solid unit. Most building constructed since the 1920s will feature cavity walls and therefore, some form of wall tie.
What are they made of today?
Before 1978, they were manufactured from a galvanised steel which was originally thought to hold up for the lifespan of the building. However, it has recently been discovered that these types of wall ties can corrode in as little as 15 years. Modern-day wall ties are predominantly made of stainless steel. This durable material can withstand water and cement corrosion without the need for a protective coating. They are low-maintenance and are individually manufactured to reduce wasted material.
How are they installed?
When a wall is being built, wall ties are placed in-between bricklayers and extend to reach both sides of the cavity. They should be pressed down firmly into place and then fixed with fresh mortar before continuing with the build. Each wall tie must be long enough to span the relevant cavity and embed into the mortar on either side for at least 62mm.
How do wall ties work?
They provide an internal support by linking two free-standing walls together. The tie design also offers a means of preventing water from transferring to the outside of the wall. This usually comes in the form of a twist at the centre.
What are the building regulation rules for wall ties?
When a building is inspected, wall ties will be taken into account. There are a number of rules that apply for UK buildings including:
You must have 2 ½ wall ties per square meter of masonry.
The maximum horizontal spacing is 900mm and the maximum vertical spacing is 450mm.
Ties should be laid to a slightly ‘outward’ fall to prevent water from passing into the inner leaf.
Ties should be manufactured from stainless steel.
The placement and spacing of wall ties differ around windows, doors, roof verges and movement joints.