Construction Technology

Question 1

What is required for an external wall to tie in together and to make it safe?

Answer 1

Wall ties are required which are metal components (stainless or galvanised) used in a cavity wall to connect the outer (external) leaf to the inner (internal) leaf of a masonry wall. They allow the 2 leaves to act together structurally and transfer lateral loads like winds.

Typically spaced at 400mm vertically and 900 horizontally. Extra ties are placed around openings like windows, doors and at wall edges.

Head restraints are ties or fixings at the top (head) of a masonry wall used to restrain the wall against lateral movement (sideways forces) at the point where it meets elements like floors, roofs, beams.

This helps prevent the top of the wall from moving especially under wind load or accidental impact.