Wall ties, also known as brick ties, are usually used in buildings with cavity walls. They join two leaves of cavity walls together, enabling the two parts to act as a homogenous unit. Hidden from view after the construction, wall ties play an important role in ensuring the stability of a building. Poorly installed or short wall ties can lead to serious structural issues, such as damp penetration, cracks or even collapse of the outer masonry leaf. Wall ties are typically made from fire and corrosion-resistant materials and include drip formation to avoid water passing to the inner leaf.

In standard brick-to-block construction, wall ties are built in the leaves during the construction. To ensure wall ties are appropriate for tying the leaves, you should press down in and surround them with fresh mortar and ensure they are never pushed into a pre-built joint. You should install them with a slight fall to the outer leaf but not towards the inner leaf, as this can provide a path for moisture to cross the cavity. The drip part of the tie should point downwards and be positioned next to the centre of the open cavity. In other kinds of cavity wall construction, for example, thin joint blockwork and steel frames or timber frames, cavity wall ties are installed after the construction of the inner leaf and during the build of the masonry's outer leaf.