The method of Cavity Wall Construction was introduced into Europe during the 19th Century and developed widespread use in the 1920’s, this gave rise to a whole new construction method and help conquer the inconveniences that were seen with solid wall construction. A cavity wall in a relatively old property will normally consist of two 100mm skins of brickwork separated by a gap of approximately 50mm – 70mm.
The two 100mm of brickwork which are acting self-sufficiently are not strong enough to carry the loads independatly and it is a requirement of the Building Regulations that both skins of brickwork are tied together at regular intervals using cavity wall ties. The wall ties that are used can be made from galvanised steel and more recently, plastic and stainless steel.
It was common for wall ties that were utilised early on in cavity wall construction to be made from iron however, these are not acceptable in modern construction as they are seen to rust very easily and be very brittle. The current Building Regulations state clearly that stainless steel ties are to be specified when any works are being carried out to replace existing wall ties although other ties can be used so long as they are approved by the British Agreement Board.
How do we replace Wall Ties?
Existing wall ties are located using a specified metal detector to find the current pattern and density of existing wall ties. One the existing ties are located, they are then exposed to find any defects which may be apparent.
If the survey results indicate corroded or insufficient ties, our Surveyor will advise on the most suitable replacement strategy.
The Wall Ties that we use are a Double Mechanical Precision Pre-Torqued Ties. These unique wall ties with their special coated black stainless steel precision limited torque nut along with the precision modified stainless steel bar provides a fixing system which allows;
- Continuous fixing to inner and outer leafs
- Pull testing of the inner leaf after fixing
- Inner leaf fixes to pre-torqued level before outer leaf is engaged