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. A series of crack repair rods are bonded across cracks in walls to create hidden tension ties that reconnect and strengthen masonry.

Stainless steel brick stitching bars have a tensile strength 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  specifical formulation polymer-modified grout for bonding crack stitching bars in masonry walls. The structural repair system integrates Thor Helical bars’ axial strength and elasticity 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. Thor Helical crack-stitching bars conform to BS EN 845-1: 2013 as tension ties for strapping and stitching cracked masonry and meet UKCA and CE marking conditions.

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

PRODUCT SPECIFICATION: Thor Helical crack stitching bars

  • Material    AISI304 grade Austenitic Stainless Steel
  • 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 (Testing to EN 846-4)

BS EN 845-1:2013 states that the bars need to provide 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. The height of the slot is at least 3mm more than the 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


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