Wall Ties

The corrosion and failure of cavity wall ties is a significant and widespread problem which, if not accurately identified and dealt with at an early stage can lead to serious and expensive structural damage.  Masonry cracking results from various causes, so it is important that wall tie corrosion is recognised as the root of the problem and both the cause and effect are properly remedied.  There are a number of properties which are most at risk, i.e. buildings subject to higher than normal exposure, for example, near the Coastline or on exposed hills or in areas subject to high industrial pollution.  Properties  built between 1900 and 1940 may be susceptible to cavity wall tie failure and this including post war buildings with  vertical twist ties which may have substandard coatings owing to shortages  just after the war, or indeed buildings constructed during the building boom years, particularly in the early 1970s.
 
Buildings over 35  years old with galvanised vertical twist ties or buildings over 20 years old with galvanised wire ties may also be at risk and it is important that the following evidence is monitored.
 
A. Horizontal cracks and rendering usually in the mortar joints, approximately every 18”.
 
B. Opening up of mortar joints.
 
C. Vertical or diagonal cracks between the horizontal cracks.
 
D. Bulges or bowing in the wall surface.
 
E. Lifting of the roof edges particularly at the gable ends.
 
Our experienced qualified wall tie surveyor has valuable local knowledge about types of mortar and ties used and site testing inspections can be arranged free of charge and without obligation and this will include the use of a metal detector to determine the tie pattern and density and a boroscope to view inside the cavity to check the composition and condition of the inner leaf and to determine the condition of the wall ties.
 
Once the problem has been identified, the sooner it is dealt with the better.  There are a number of options and systems which we may consider, and the system or wall tie type, pattern and installation is usually ascertained during our first inspection.

Wall Tie collapse - end wall.

Wall Tie collapse - end wall.