There are a number of corrosion resistant stainless steel remedial wall ties that are designed specifically for cavity wall tie replacement in domestic housing and for ease of use. The most common retrofit brick tie types are:
A profiled and twisted remedial wall tie that is driven into a pilot hole. Work hardened blades cut a spiral interlock into brick, block & concrete walls as the cavity ties are driven by a series of impacts. Tiny 6mm pilot holes enable extremely quick wall tie installation with minimal disruption to the facade or to cavity insulation. Helical ties can be used in all masonry substrates. A setting tool in a hammer drill facilitates the easiest and fastest retrofit wall tie replacement system available.
An effective wall tie system transfers static and live loads across the cavity, enabling load-sharing by both inner and outer walls. Typically cavity wall ties are bedded in a mortar bed joint as a building is constructed.
Cavity wall tie failure can be a consequence of a construction defect; for example where the original ‘built-in’ cavity wall ties have been omitted, incorrectly fixed or fitted with masonry ties that are too short. Alternatively failure may be a result of a buildings ageing process, whereby wall tie corrosion may have compromised the load-sharing capacity of the wall structure.
BRE Recommended Drilling Pattern for 50-300mm cavity width and both leaves more than 90mm thick
A: Maximum 225mm above DPC/ground level
B: Vertical maximum 300mm around openings
C: 225mm from corners
D: Minimum 450mm from internal corner of brickwork return
E: 900mm apart horizontally in a diamond pattern
F: 450mm apart vertically in a diamond pattern
