Cavity Wall Ties / Stitching

The symptoms and possible dangers of defective cavity wall ties

Evidence of horizontal cracking to external walls.

Evidence of horizontal cracking in brickwork, external rendering or building blocks can often be caused by the failure of cavity wall ties. Cavity wall ties are metal restraints that prior to 1978 were manufacture from galvanised steel. These cavity wall tie restraints were installed into the brickwork at the time of construction to tie the two skins of brickwork together. They were expected to last the lifetime of the building but it was found that some cavity wall ties corroded after only 15 or 20 years. When the cavity wall ties corrode they expand to several times their original thickness, which causes the wall to crack at the mortar joints and often result in major damage and sometimes collapse of the wall.

The Tapco HomeDry.com method of replacing cavity wall ties and repairing cracked brickwork

Tapco HomeDry.com use a double expansion remedial cavity wall tie that is manufactured from corrosion resistant Austenitic 304 grade stainless steel tie bars with Neoprene sleeves. These cavity wall ties have a unique ‘tall-nut’ which when turned with a setting tool, rotates the whole tie bar, forcing the inner leaf sleeve to open and grip the masonry. At a factory set torque level, the end of the ‘tall nut’ shears away and the remaining nut is forced down the bar to expand the sleeve and grip the outer leaf.

Cracked masonry is stabilised by bonding stainless steel bars into appropriate bed joints or cut slots using epoxy resin. Tensile loads are redistributed along masonry to minimise further developments of the cracks.

The Tapco HomeDry.com guarantee for cavity wall ties and structural brickwork repairs

• Cavity Wall tie replacement and structural stitching is covered by our Twenty Year Guarantee.
• For a single premium our guarantee can be insured by the Guarantee Protection Insurance (GPI).