Crack Stitching Kit

Crack Stitching Kit

A crack stitching kit containing everything required to strap and stitch across cracks in wall. Conform to BS EN 845-1: 2013 and conditions for CE marking for the retrofit reinforcement of cracked brickwork.  Tensile loads in excess of 8kN


The Thor Helical Crack Stitching Kit contains everything needed to reconnect and strengthen cracked brickwork and fractured masonry. A series of durable stainless steel helical rods are discretely bonded into slots formed into mortar bed joints to stitch across cracks, spread tension loads and create a reinforced zone that inhibits progression of the crack.

Crack Stitching Kits contain:

  • 10 x high tensile stainless steel helical bars in a selection of diameters. The helical profile of the rods provide an excellent key for bonding into mortars.
  • 1 x 3L tub of WHO60® polymer modified grout that has been specifically formulated to bond crack stitching bars into brick and masonry walls.
  • 1 set of tooling components comprising a grout applicator, a power-mixing paddle and a pointing tool

This effective, reliable and durable brick stitching system provides resilience against further cracking with minimal cost and little disruption.

Components are supplied in sufficient quantities to make a minimum of 48 kits.  The components can be packed individually in distributor-supplied ‘crack stitching kit’ boxes.


Thor Helical crack stitching bars are available in AISI304 grade Austenitic Stainless Steel. AISI316 stainless bars are available on special request. The bars are supplied in the following standard sizes

  • Lengths: 1.0m, 1.5m and 2.0m
  • Diameter: 5mm, 6mm, 7mm, 8mm and 9mm

BS EN 845-1:2013 National Annex NA states that the bars need to provide an equivalent performance to the prescriptive 30mm x 5mm lateral restraint straps and the tension straps should have a declared tensile load capacity of at least 8kN

TYPICAL PERFORMANCE LOADS 400mm bar-embedment length in WHO-60 Grout (taken from CE Mark Testing)

Bar Diameter
Bars per Joint Tension Load
6mm Single Bar 8.39kN
7mm Single Bar 9.75kN
8mm Single Bar 11.06kN
9mm Single Bar 11.50kN
6mm Double Bar 16.00kN
7mm Double Bar 17.65kN
8mm Double Bar 17.65kN
5mm Triple Bar 14.34kN

Single bars bedded 20mm deep: Double bars placed 15 & 25mm deep: Triple bars buried 10, 20 & 30mm deep. Height of slot at least 3mm greater than diameter of crack stitching bars. Depth of slot 35-40mm.  All bars bonded in WHO-60 polymer modified grout



CSA (mm2) 0.2% Proof Stress (N/mm2) Ult Tensile Strength (N/mm2)* Mean Tensile Capacity #
5mm 6 >880 1025 – 1225 7 kN
6mm 8 >870 1025 – 1225 9 kN
7mm 10 >880 1025 – 1225 11 kN
8mm 13 >790 1025 – 1225 14 kN
9mm 16 >850 1025 – 1225 17 kN

* Ultimate Tensile Strength is measured within a calibrated tolerance of +/- 2%
# Mean Tensile Capacity is an indicative value derived from CSA x Mean UTS



Physical Properties Strength
Compressive Strength – 7 days 35N/mm²
Compressive – 28 days 55N/mm²
Tensile Strength – 28 days 5N/mm²
Flexural Strength – 28 days 12N/mm²
Young’s modulus (fully cured) 13kN/mm²

This video guide demonstrates the method of stitching cracked brickwork using stainless steel helical reinforcing bars, bonded into walls with WHO-60 polymer modified grout. The crack stitching kit offers a quick, simple and durable solution for repairing cracked masonry walls