Crack stitching repairs cracked masonry by cutting slots into the bed joints across the crack, bonding stainless steel helical bars into them with a specialist grout, and repointing. It restores tensile continuity, so the wall acts as one piece again. It does not cure ongoing foundation movement, so we only stitch once the cause has been dealt with and a structural engineer is satisfied the wall is ready to repair.
What is crack stitching and how does it work?
Brick and block walls are strong in compression but weak in tension. When something pulls a wall apart, whether foundation movement, a failed lintel or restraint problems, a crack opens and the two halves of the wall stop sharing load. Helical bars are thin stainless steel bars twisted into a spiral. Bedded into the mortar joints with grout, they span the crack and lock both sides together again, much like a hidden reinforcing tie.
The engineer's specification sets the bar length either side of the crack, the vertical spacing between stitched joints, and whether the inner leaf of a cavity wall needs stitching too. We follow that specification on site. It is one of the most common repairs in our structural crack repair and underpinning work in Liverpool, because so many cracks only need reinforcing once the cause has gone.
When is crack stitching the right repair?
Stitching suits masonry that has cracked but is now stable. Typical examples:
- Cracks remaining after a subsidence cause, such as a leaking drain, has been repaired and the ground has had time to settle.
- Cracking above an opening after a failed lintel has been replaced.
- Stepped cracks at corners or at bay junctions where the engineer is content that movement has stopped.
- Cracks in gable or flank walls being restrained as part of a bowing wall repair.
- Older settlement cracks that monitoring shows are no longer moving.
When is it the wrong repair?
| Situation | Why stitching alone is not enough |
|---|---|
| Active subsidence or heave | The ground is still moving, so the wall will crack again elsewhere. The cause comes first. |
| Corroding wall ties | The ties keep expanding; remedial wall ties are needed. |
| Movement not yet understood | The engineer may ask for crack monitoring before deciding. |
| Badly distorted or unstable masonry | Sections may need rebuilding, or temporary support, rather than stitching. |
Crack stitching is structural work carried out to a chartered structural engineer's specification. Please do not cut into or stitch structural walls yourself. If a crack is opening quickly or the wall looks unstable, keep people away and get urgent professional advice.
What happens on a crack stitching job?
- Confirm the cause is dealt with. We review the engineer's report and any monitoring, drain or lintel work already done.
- Set out the repair. Bed joints to be stitched are marked to the specified spacing and length either side of the crack.
- Cut and clean the slots. Mortar joints are cut to the specified depth and cleaned out so the grout bonds.
- Bond in the bars. Grout is placed, the helical bar pressed in, and covered with more grout.
- Fill the crack and repoint. The crack is filled or grouted as specified, damaged bricks replaced, and joints repointed to match as closely as practical.
- Internal making good. Plaster cracks inside are repaired once the structural work is complete.
How does crack stitching compare with other ways of repairing a crack?
Homeowners are often offered one of three things for a cracked wall: filling it, rebuilding it, or stitching it. Filling a structural crack with mortar or sealant restores the look but not the strength, so the wall still behaves as two separate pieces and the line tends to reappear. Rebuilding takes out the damaged brickwork and lays it again, which is right where bricks are badly broken or the wall has distorted, but it is more disruptive and needs temporary support on loaded walls. Stitching sits between the two: the existing masonry stays in place and is reinforced across the crack, which is why engineers specify it so often for stable cracks in otherwise sound walls.
Stitching can also be combined with other work. On a bay that has been partly underpinned, the engineer may call for bars across the junction between old and new so the masonry spans any small difference in movement. On a gable being restrained, stitching deals with the cracks while straps or anchors hold the wall back to the floors and roof.
Which Merseyside properties need crack stitching most often?
We see a lot of stitching on solid-walled Victorian terraces and on cavity-walled inter-war semis alike. In older terraced streets of Old Swan and Walton, cracks above bay and sash openings are typical, while the Victorian villas of Wallasey bring tall elevations where access and scaffolding shape the job. In every case the stitching follows diagnosis, not the other way round. If you are not sure what caused the crack yet, start with our structural crack repair page.
What affects the cost of crack stitching?
The main factors are the total length of crack, the number of bars the engineer specifies, whether both leaves of a cavity wall are stitched, the height and access (and whether scaffolding is needed), brick replacement and mortar matching, and internal making-good. Any investigation or cause-related work, such as drains or lintels, is priced separately. We give a written quote against the engineer's specification.
Need cracked brickwork stitched?
Call 07777 659786 or use the form to describe the crack, how long it has been there and whether an engineer has already looked. We will call back and explain how we approach crack and foundation repairs across Merseyside.
Frequently asked questions
Will crack stitching stop subsidence?
No. Crack stitching restores tensile strength across a crack in the masonry, but it does nothing to stop the ground or foundation moving. If subsidence is still active, the cause must be found and dealt with first, and the engineer decides whether monitoring or underpinning is needed. Stitching is the final repair, not the cure.
Will the repair be visible on the brickwork?
The bars sit inside the bed joints, so once the joints are repointed with a mortar matched as closely as practical to the existing, the repair is usually discreet. Where bricks along the crack are split or damaged they may be replaced. Old, weathered mortar is hard to match exactly, so some difference is often visible close up at first.
Can crack stitching be done on render or internal walls?
Yes, helical bars can be used in rendered and internal masonry walls as well as facing brickwork, with the render or plaster cut back and made good afterwards. The engineer specifies where bars go and at what spacing. Stud partitions and plasterboard are a different matter and are not stitched.
How long does crack stitching take?
A straightforward crack on an accessible wall is often a short job, while long cracks, high elevations needing scaffolding or several walls take longer. Timing also depends on the engineer's specification and on weather, since grout and mortar should not be laid in frost. We give a realistic programme with the written quote.
Is crack stitching suitable for wall tie failure?
Horizontal cracking from corroded wall ties is not cured by stitching alone, because the ties themselves keep corroding and expanding. The usual answer is remedial wall ties, with old ties treated or isolated where needed, to the engineer's specification. Stitching may then be used on any cracks that remain.