Drive Fix Remedial Helical Wall Tie 8mm x 195mm Qty 100
Drive Fix Remedial Helical Wall Tie 8mm x 195mm qty 100 for cavity walls with a cavity width of 50mm – 75mm
Available in 195mm and 220mm lenghts. Other lengths available on request.
Drive Fix Helical Wall Tie is installed using a proprietary setting tool that is used with an SDS-Plus shank hammer drill to drive and countersink the tie.
The helical design allows the tie to be driven quickly and easily into a pre-drilled pilot hole. As the tie is driven into the substrate, the fins of the tie undercut the masonry to provide an expansion-free anchorage that will withstand tension and compression loads.
Once installed the Helical Drive Tie provides a mechanical connection between a masonry façade and its backup material or between multiple widths of brick.
In general terms the fixing densities for remedial wall ties would be the same as new build – 2.5 per m² or 450 mm vertically and 900 mm horizontally in a domino five pattern. This density would, however, be subject to on site testing to ensure that the required tensile loadings are being achieved.
To Install Helical Drive Ties you will need to drill a 5.5 – 7mm pilot hole into the substrate.
Grade 304 Stainless Steel.
Drive Fix Helical Remedial Wall Ties are ideal for walls with a render finish.
If the wall is rendered, pebble dashed or coated with anything, this will reflect on the method of installing the wall ties and the type of remedial tie. For starters, is the material sound? Drilling causes vibration and may shake loose or crack old render. Could there be services or pipes under the coating, a metal detector should help here. The use of a remedial cavity wall tie designed for mechanical expansion should be avoided, because without extreme care and many aborted holes, some of these will inevitably be drilled near the edge of a bed joint, where post-torsion expansion can ruin the fix, see below), leaving the wall tie useless and a waste of time and money. Mechanical expansion ties work by exerting expansive force outward, through the brick or stone; rather like a rawlbolt. If the material cannot take these stresses, the material fails and the fix is compromised. Thus most manufactures of these wall ties recommend the wall ties are fixed ‘centre of brick’ to ‘centre of brick’, which is hard when the brick is hidden behind render (not to mention the inner leaf which is always hidden).