Cavity Wall Tie Reports
The external walls to the majority of most properties built after 1920 are of cavity wall construction.
What is a Cavity Wall Tie?
A cavity wall consists of an outer leaf of brickwork, a cavity (usually 50mm wide), and an inner leaf of blockwork. The outer and inner leaves are then tied together by galvanised steel wall ties which are embedded into the mortar joints of each leaf.
What problems can occur?
The most common cause of cavity wall tie failure occurs when the tie begins to corrode due to the mortar jointing becoming consistently wet. The moisture causes the steel to eventually rust and this corrosion causes expansion of the tie which in turn causes the mortar to crack and ultimately weakens the structure.
Corrosion may also cause the wall tie to snap within the cavity which will result in the outer and inner leaves no longer being held together.
The Report
The investigation will involve the detection of the wall ties using metal detection equipment followed by an endoscopic inspection via small drill holes to assess the condition of the wall ties.
If the ties are indeed corroding or are insufficient then replacement will be necessary.