Wall ties are used to join the internal and external wall of a cavity which are installed during construction.
Over time these wall ties can corrode especially in old properties where steel ties were used.
Wall tie corrosion is common in coastal areas, due to salt laden driven rain.
Most buildings will out last the life expectancy of the wall ties,
Wall tie replacement will be necessary at some point in most buildings with cavity walls.
Repointing Brickwork - Isle of Wight