What are Remedial Wall Ties?
Wall ties are an essential element for the stability of a cavity wall structure, tying its weather protecting brick facade to the main body of a building. Cavity walls have been a common feature of buildings in the UK for over one hundred years. Two leaves of brick or stonework are held together using metal straps or “wall ties”. The cavities between the two leaves of masonry provide an affective barrier to water penetration and also acts as an insulation layer. An effective brick tie system transfers static and live loads across the cavity, enabling load sharing by both inner and outer walls. Typically cavity wall ties are bedded in a mortar bed joint as a building is constructed.
But, unless the ties are of stainless steel or vey heavily galvanised mild steel, there is a tendency for the ties to rust making the wall less secure and sometimes causing bowing of the brickwork. Mild steel ties have a shorter life than the brickwork and, during the life of the building, can need replacement.
Most houses built in the last twenty years will have been constructed of stainless or heavily galvanised ties which are proof against decay but houses prior to 1980 cannot be presumed to be immune, hence the need for inspection.