Wall Tie
/wawl ty/
Also known as: cavity wall tie, butterfly tie, double-triangle tie, twisted tie, stainless steel tie
Definition
A metal connector used to link the two leaves of a cavity wall, transferring lateral wind loads between them while allowing differential movement. Wall ties must be stainless steel or suitably coated to resist corrosion in the cavity environment.
In Practice
Wall ties are built in as the cavity wall is constructed, typically at 900mm horizontal and 450mm vertical centres, with closer spacing around openings. Corroded wall ties in older properties (pre-1980s mild steel ties) are a significant structural problem - replacement by resin-fixed stainless steel remedial ties is often required.
UK Building Regulations
Approved Document A - Structure
BS EN 845-1 covers wall ties. Minimum 3.2mm diameter stainless steel (grade A2 or A4). Ties must slope slightly outward towards the outer leaf to prevent water tracking inward.
See Also