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

In standard brick-to-block construction, wall ties are built into the leaves during construction. To ensure proper installation, press them into fresh mortar, ensuring they are not pushed into a pre-built joint. Wall ties should be installed with a slight fall towards the outer leaf to avoid moisture crossing the cavity. The drip part of the tie should point downwards and be positioned near the center of the open cavity.

In other types of cavity wall construction, such as thin joint blockwork, steel frames, or timber frames, cavity wall ties are installed after the inner leaf is constructed and during the build of the masonry's outer leaf.