Wall tie replacement
Wall ties are used to join the internal and external walls (or leafs) of a cavity wall and are installed during construction.
Over time these wall ties can corrode and require replacement – particularly where ungalvanised or inadequately protected steel wall ties have been used. The expansion caused by this type of corrosion can force apart mortar joints – causing cracking of masonry. Other symptoms include bulging of walls and the lifting of roof edges. In severe cases wall collapse has even been reported.
Wall tie corrosion is particularly common in buildings in coastal areas (due to salt-laden driving rain) and in masonry that has been constructed using corrosive black ash mortar. However because most buildings will outlast the life expectancy of the wall ties installed during construction, wall tie replacement will be necessary at some point for most buildings constructed using cavity walls.
Replacement of wall ties may also be necessary if the original wall ties used to construct a cavity wall were installed incorrectly – for example, where too few ties were installed (low tie density), where the wrong type of wall ties were used, or where site control during installation was poor.
Replacement Wall Ties
Wall tie replacement is carried out using special types of wall tie which have been specifically developed for use on existing walls. Wall ties intended for use when constructing new walls should not normally be used for wall tie replacement.
Three types of wall tie are typically used for wall tie replacement applications. These are:
Choosing which type of replacement wall tie to use will depend on a number of factors including the type of masonry, whether or not the cavity contains insulation material, and fire performance requirements. Please contact our technical department on 01403 210204 or submit an enquiry for further details.
Replacement wall ties are supplied in a variety of lengths due to the fact that the width of the cavity can vary considerably between cavity walls.
Wall Tie Replacement Procedure
BRE Digest 329 and BRE Digest 401 give detailed advice on suggested procedures for the replacement of wall ties in masonry. Broadly speaking, the wall tie replacement procedure can be divided into five elements:
- Investigation – Collection of information about type and condition of masonry, cavity width, type and condition of existing wall ties etc…
- Isolation / removal of existing wall ties depending on condition.
- Specification – choice of remedial wall tie type – density and layout of remedial wall ties.
- Installation of replacement wall ties
- Quality control – visual checks, torque testing, etc…
Due to the specialist knowledge and equipment required, wall tie replacement is normally carried out by wall-tie replacement contractors who are able to offer insured guarantees on their work.
Other types of masonry repair such as crack stitching and masonry waterproofing are often carried out
Wall Tie Replacement Contractors
Wall tie replacement is a job for a skilled contractor. If you would like a quote from a wall tie replacement company in your area, please contact our technical department on 01403 210204 or submit an enquiry.