Crack Stitching Bars

Crack Stitching Bars

High tensile stainless steel crack stitching bars are used to reinforce cracked masonry walls.  They extend 500mm either side of the crack and withstand a tensile load of at least 8kN.  Bars are available in a selection of sizes.


Crack stitching bars provide an effective solution for repairing and reinforcing cracked brickwork.  Crack repair rods are bonded across cracks in walls to reconnect and strengthen masonry.

Stainless steel brick stitching bars have a tensile strength that is double that of conventional rebar and a spiral twist that permits a degree of torsional yield within elastic limits and provides an excellent key for bonding into mortars.

WHO60® is a polymer modified grout that has been specifically formulated to bond crack stitching bars in masonry walls. The structural repair system integrates the axial strength and elasticity of Thor Helical bars with the properties of WHO60® grout to enhance the tensile, shear and flexural capacity of masonry walls.

Anchored across fractures, the Thor Helical crack stitch ties progressively accumulate building loads and disperse them back into the structure, spreading loads and strengthening cracked walls.  This effective masonry stitching repair provides resilience against further cracking with minimal cost and little disruption.

Stainless steel bars for crack stitching are supplied in lots of 500 and packed in resale bundles of 10 and 25.


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


TYPICAL PERFORMANCE LOADS in 35-40mm slot at 400mm embedment length (taken from CE Mark Testing)

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

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.



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

This video demonstrates the Crack Stitching method of strengthening cracked masonry using stainless steel helical reinforcing bars, bonded into cut slots, with WHO-60 polymer modified grout.  It offers a quick, simple and durable solution for repairing cracked masonry walls