Wall Tie Replacement
Wall Ties – metal ties which connect at regular intervals the outer and inner leaves of a cavity wall.
Earlytypes are of thick ungalvanised metal, often in fishtail pattern shape. These can rust and expand up to six times their own thickness in the outer leaf of a masonry wall. This will cause the masonry to bulge out and eventually “pop” and become detached from the rest of the wall.
High winds can then cause considerable damage to walls, especially in exposed conditions in buildings over two storeys high. This is accentuated in coastal areas where high salt content of air accelerates corrosion.
The remedy is to locate the existing ties in the mortar joints with a metal detector, expose the end and isolate it with quick-setting plastic foam then repoint the joint. New ties are then installed to the manufacturer’s specifications (usually around 2.5 per square metre and increased around window and door openings). They are usually installed through the centre of the brick then coloured mortar is used to disguise the entry hole. Existing ties will only be removed in rare cases if required. Modern wire ties are often not isolated.