Cracked masonry is best stabilized by bonding HeliBar (helical stainless steel bars) into appropriate bed joints or cut slots, in bricks, blocks or stonework with HeliBond cementitious grout. Tensile loads are redistributed along the masonry to minimize further developments of the crack which may occur with simple injection methods.
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1. Rake out or cut slots into the horizontal mortar beds, a minimum of 20″ either side of the crack, to the specified depth.
2. Clean out slots and flush clean with water and thoroughly soak the substrate within the slot.
3. Using the Helifix Pointing Gun Kit, inject a bead of HeliBond along the back of the slot.
4. Using the brick jointer, or similar, push one HeliBar into the grout to obtain good coverage.
5. Insert a further bead of HeliBond over the exposed HeliBar, finishing ½” from the face, and ‘iron’ into the slot using a brick jointer.
6. Re-point the mortar bed and make good the vertical crack with CrackBond TE3.
Where cracks are less than 20″ from an external corner (A) or an opening (B) at least 4″ should be bent around the corner and bonded into the return wall or bent and fixed into the reveal, avoiding any DPC membrane.
Where two or more cracks are close together these may be stitched using one continuous length of HeliBar which must be long enough to extend 20″ beyond the outer cracks. e.g. if there are three cracks, each 10″ apart, then the overall length of HeliBar required would be 60″.
The horizontal slot, normally the mortar bed, can be cut using a twin diamond blade chaser with vacuum attachment, an angle grinder or a mortar chisel.
All mortar must be removed, together with any loose debris, to ensure a sound bond. Prepare the slot with HeliPrimer WB or thoroughly wet the slot with clean water.
As standard, slots should be 10mm wide to accommodate the 6mm diameter HeliBar.
HeliBond grout is the recommended bonding agent. PolyPlus resin is used for smaller jobs and where loads are to be rapidly applied.