Guide
Crack stitching explained
By Structural Repairs UK · Updated 2026-11-09
Crack stitching is a masonry repair in which stainless steel helical bars are bonded into slots cut across a crack, tying the cracked brickwork back together so it acts as one wall again. It works well once the cause of the crack has stopped, but it is not a fix for ongoing movement, failed wall ties or a failing lintel.
How does crack stitching work?
Crack stitching works by bridging a crack with thin stainless steel helical bars set into the mortar joints. Slots are cut into the bed joints across the crack, usually every few courses, and each bar runs well past the crack on both sides. The bars are bedded in a special grout and the slots are repointed to match. The bars spread stress along the wall instead of letting it concentrate at the crack, and the crack itself is grouted or filled so the wall is sealed.
What happens on the day of a crack stitching repair?
A typical crack stitching repair takes 1 to 3 days. The slots are cut with a masonry saw and cleaned out, grout is injected, the bars are pressed in and covered with more grout, and the joints are repointed. Inside, the matching crack in the plaster is usually stitched or reinforced too, then made good. Dust is the main disruption, so furniture is covered or moved. Scaffolding is only needed where the crack runs high up the wall. Once the mortar weathers, the repair is usually hard to spot.
When is crack stitching the right fix?
Crack stitching is the right fix when the movement that caused the crack has stopped, or its cause has been dealt with, and the wall is still broadly in line. Most subsidence claims end with crack stitching and making good rather than foundation work. It also suits older settlement cracks that have been stable for years but leave the wall weaker than it should be, restoring that strength without rebuilding.
- Old settlement cracks that have stopped moving
- Subsidence cracks once the cause is fixed and readings are stable
- Cracks at bay window and extension junctions, with tie-in
- Cracks beside openings where the lintel is sound
- Cracked brick arches that are still in shape
When is crack stitching not the right fix?
Crack stitching is not the right fix while a wall is still moving, because the crack simply reopens beside the bars. If subsidence is active, the cause has to be dealt with first and the building monitored until it is stable. Stitching will not cure horizontal cracking from corroded wall ties, which need replacing. A crack above a window caused by a failing lintel needs the lintel replaced. Badly bulging or displaced brickwork may need restraint or partial rebuilding instead.
Some vertical cracks in long walls come from thermal or moisture movement that repeats every year. Stitching these rigidly can push the cracking somewhere else, and a movement joint may be the better answer. Cracks of category 3 or more on the BRE scale, roughly 5 mm and wider, should be assessed by an independent chartered structural engineer before a repair is specified. Your engineer will confirm whether stitching suits the crack.
How much does crack stitching cost?
Crack stitching has a guide price of £80 to £180 per metre of crack inc VAT. Small jobs usually carry a minimum visit charge of about £350 to £500, and repointing over the stitched line in matching mortar is about £30 to £60 per metre. A single crack outside only, up to about 2 m, is usually £400 to £900. Height, scaffolding, hard bricks and internal making good all add to the price. Figures vary by region and access and are confirmed in writing after a survey.
Do I need approval or my insurer’s agreement?
Crack stitching on its own is often treated as a repair rather than notifiable building work, but check with building control if it is part of a wider structural scheme. If the crack is part of a subsidence claim, tell your insurer before permanent repairs start and let them agree the schedule. Where a crack runs through a party wall in England or Wales, the Party Wall etc. Act 1996 may apply. Where the repair needs an engineer’s design or sign-off, an independent chartered structural engineer is appointed, and we can arrange this.
Questions about this guide
How long does crack stitching last?
Crack stitching lasts as long as the wall around it stays stable. The stainless steel bars do not rust, so the repair itself is durable. If the cause of the movement has not been dealt with, though, new cracks can form next to the stitched area. That is why the cause is confirmed first, and monitoring is used where subsidence was involved.
Will crack stitching show on my brickwork?
Crack stitching usually shows a little at first, as fresh mortar along the stitched joints. Matching the mortar colour and joint profile keeps it discreet, and most repairs blend in as the mortar weathers. Badly broken bricks along the crack may need replacing with matching bricks, which also helps the finished look.
Can crack stitching be done from inside?
Yes, crack stitching can be done on the inside face, and internal cracks are often stitched or reinforced before replastering. In a cavity wall each leaf is treated separately, so a crack that shows outside needs stitching on that face too. Your engineer or surveyor will say whether one face is enough for a particular crack in a solid wall.