HeliFix crack stitching in Melbourne

A crack in a brick wall is a symptom. Something has moved — the footing, the ground under it, a lintel, a wall that was never tied properly — and the brickwork has failed at its weakest line, which is almost always the mortar. Filling that crack with mortar or sealant puts the weakest line straight back where it was. The next dry summer, the crack returns in the same place.

Crack stitching does something different. Helical stainless steel bars are bonded into the horizontal mortar beds so they cross the crack and extend well past it into sound brickwork on both sides. The bars take the tension the masonry cannot, and the load that was concentrating at one line gets spread across a much wider area of wall. The wall starts behaving as one structure again instead of two pieces either side of a split.

It is a repair, not a cover-up, and it is done from the mortar joints rather than by rebuilding. On most houses there is no need to take down and relay brickwork, no need to remove the roof, and no need for anyone to move out.

Melbourne is unusually hard on masonry, and it is worth understanding why, because it changes what the right repair is.

• Reactive clay soils. Much of Melbourne — particularly the north and west, and the basalt plains through Sunshine, Werribee and Craigieburn — sits on clay that swells when it gets wet and shrinks when it dries. Under AS 2870 a lot of it is classified moderately to highly reactive. The ground under your footings genuinely moves up and down with the seasons.
• Drought and downpour cycles. Clay that has shrunk through a long dry spell and then swollen after heavy rain moves a house unevenly, because one side of the building is usually shaded, paved or planted differently from the other. That differential movement is what opens a crack.
• Trees. A mature gum or liquidambar close to the house draws an enormous amount of moisture out of clay in summer. Cracking that appears on the tree side of a building, worst in February and March, is a classic pattern.
• Water going where it should not. A leaking box gutter, a disconnected downpour, a cracked stormwater line or a broken sewer will soften the ground under one section of footing and nothing else. We find this constantly — the crack is the symptom, the drain is the cause, and stitching without fixing the drain is money wasted.
• Older footings. Victorian and Edwardian homes were built on shallow brick footings or timber stumps that were never designed for today’s soil moisture swings. Period homes across the inner suburbs move seasonally as a matter of course.
• Failed lintels. Steel lintels over windows and doors rust, and rusting steel expands. That lifts the brickwork above it and opens horizontal cracking at the lintel line. This needs the lintel replaced, not stitched.
• Missing or corroded wall ties. In cavity brickwork the outer leaf is tied back to the inner structure. When those ties corrode, the outer leaf bulges and cracks independently. That is a tie problem, and the fix is remedial ties rather than stitching alone.

Half the value of getting someone experienced to look at a crack is being told which of these it is. The repair for reactive clay movement is not the repair for a rusted lintel, and neither is the repair for failed wall ties.

We are a licensed HeliFix applicator and HeliFix approved installer, trained and supported by HeliFix Australia, and we use the full system rather than picking parts of it.

• HeliBar helical bars. Austenitic stainless steel bars with a helical profile that grips the grout mechanically along their whole length. They are installed into slots cut in the mortar beds, typically at set vertical spacings across the crack, and extend a specified distance into sound masonry either side.
• HeliBond cementitious grout. The bars are bedded in HeliBond, a high-strength thixotropic grout that is pumped into the slot so the bar is fully encapsulated. It gains strength over a standard cure and reaches its full compressive strength at 28 days.
• ResiTie remedial wall ties. Where the outer leaf of a cavity wall has lost its ties, ResiTie resin-fixed remedial ties re-connect it to the inner structure. On a lot of jobs the wall needs both — stitching for the crack, ties for the leaf.
• Bed joint reinforcement. Where a whole section of wall is weak rather than one crack line, bars can be installed in successive bed joints to reinforce the panel and distribute load over a larger area.

The system is not new and it is not experimental — helical bar crack stitching has been used on masonry for more than thirty years, including on heritage buildings where rebuilding is not an option.

1. 01We look at the whole building, not just the crack. Where the crack starts and finishes, which way it steps, whether it is wider at the top or the bottom, what is happening at the lintels, the roof drainage, the ground levels and the trees. A stepped crack that is wider at the top tells a different story from one wider at the bottom.
2. 02We tell you whether stitching is the right repair. Sometimes it is not, and we will say so. If the footing is still actively moving, stitching alone will not hold and the underlying movement has to be addressed first — usually by a structural engineer, and sometimes by underpinning or drainage work before we touch the brickwork.
3. 03Slots are cut into the mortar beds. Cutting is done in the mortar joints, not through the bricks, using dust extraction. The depth and spacing follow the HeliFix specification for the wall type.
4. 04Grout, bar, grout. A bead of HeliBond goes into the back of the slot, the HeliBar is pressed in and worked into the grout, and a second bead covers it so the bar is fully encapsulated.
5. 05The joints are made good. Slots are pointed up with mortar matched to the existing — colour, texture and joint profile. On rendered walls the crack is prepared and the render made good over the repair.
6. 06You get documentation. Photographs of the works and, where required, a HeliFix Installation Certificate recording what was installed and where.

Most residential crack stitching jobs are two to three working days on site. The wall is usable immediately; the grout continues gaining strength afterwards.

Good candidates: stepped cracking following the mortar joints in brickwork; vertical cracking at the corners of a building; cracking radiating from window and door openings; separation between an addition and the original house; cracking in solid double brick, brick veneer and rendered masonry; cracked masonry on heritage buildings where rebuilding would destroy original fabric.

Not a stitching job on its own: cracking caused by a footing that is still actively subsiding, which needs the movement stopped first; horizontal cracking at a lintel caused by a rusting steel lintel, which needs the lintel replaced; a bulging outer leaf caused by failed wall ties, which needs remedial ties; cracking in concrete rather than masonry, which is usually a resin injection or concrete repair job; hairline cracking in plaster inside, which is cosmetic and not structural.

If you are being quoted crack stitching for any of the second group without the underlying cause being addressed, get a second opinion.

Sometimes, and we will tell you honestly which situation you are in.

For a straightforward crack on a stable building — seasonal movement that has settled, no ongoing subsidence, no structural risk — an engineer is generally not required and we can assess, quote and repair.

An engineer is needed where the building is still moving, where the cracking is severe or widening, where a wall is out of plumb or bulging, where the repair is on a commercial or multi-storey building, or where an insurer or owners corporation requires an independent structural assessment. In those cases we refer you to a structural engineer we work with, and we install to their design.

This also matters for warranty, which is covered below: a HeliFix-warranted repair runs through an engineering design that HeliFix head office approves.

A few jobs that show the range. Client details are kept private.

• Brunswick — solid brick wall, 20 lineal metres of bar. A solid brick wall with cracking through several bays. Twenty lineal metres of HeliFix bar installed from the outside face working in, then the joints repointed with mortar matched to the existing brickwork. Two to three days on site.
• Balwyn North — crack at a box gutter. A specialist roof report flagged cracking in the brickwork near the flat roof and box gutter on the western elevation. One bar at the box gutter plus six to eight bars across the front corner, colour-matched repointing, and an acid wash about a week later once the mortar had cured.
• Yarraville — heritage church building. A combination job: crack stitching, bed joint reinforcement through weakened panels, and ResiTie resin-fixed remedial ties where the wall had lost its original ties. A formal HeliFix Installation Certificate was issued on completion, along with a demolition clearance date for the adjacent works.

If you would like to see photographs of similar work to your own building, ask — we keep a record of every job and are happy to send through comparable examples and client references.

On unrendered brickwork, once the slots are repointed with matched mortar, a stitched crack is very difficult to pick unless you know exactly where to look and get close. The bars sit inside the mortar bed; there is nothing on the surface. Matching is the skill — old mortar has weathered to a particular colour and texture, and new mortar has to be tinted and finished to sit with it rather than stand out as a clean grey line.

On rendered walls the repair disappears entirely under the made-good render. Where the render is old and patch-repairing would show, a full re-render or re-coat of the affected elevation gives a better result, and we will quote that as an option rather than leave you with a visible patch.

A lot of our crack stitching work is not just a repair — it has to be evidenced to somebody.

We provide written inspection and defect reports with photographs, suitable for owners corporation meetings, insurers, building managers and conveyancing. On completion we issue a HeliFix Installation Certificate recording the system installed, where it was installed and the extent of the works, signed and on our letterhead.

For owners corporations, that document is usually what allows the committee to close the matter out. For a sale, it is what turns “there was a crack” into “the crack was repaired properly by a licensed installer, here is the certificate”.

Where a HeliFix manufacturer warranty is required, the process runs in three steps:

1. 01An engineer we nominate inspects and designs the repair. The report sets out the cause of the movement and the repair design.
2. 02HeliFix head office approves the design. The specification goes to HeliFix for sign-off before anything is installed.
3. 03We install it, and HeliFix warrants the job. Installed to the approved design by a licensed applicator, the works carry the manufacturer’s warranty on top of our own workmanship warranty.

Your rights under Australian Consumer Law apply in addition to any warranty we or a manufacturer provide.

We do not publish a fixed price for crack stitching, because the honest answer is that it depends on things we cannot know until we look: how many lineal metres of bar the wall needs, how many separate crack lines there are, whether the wall is solid brick or cavity, whether access needs scaffold or an EWP, whether repointing is a small area or a whole elevation, and whether anything else — a lintel, drainage, wall ties — has to be dealt with at the same time.

What we can tell you is that the assessment costs nothing. We come out, look at the building, tell you what is causing the cracking and what the repair involves, and give you a written quote. There is no charge and no obligation, and if stitching is not the right repair we will tell you that too.

• Does crack stitching actually work? Yes, where it is the right repair for the cause. Helical bar stitching has been used on masonry for more than thirty years, including on heritage buildings. It works because it reinforces the wall across the crack and spreads load into sound brickwork, rather than filling the gap. Where it fails is when it is installed on a building whose footings are still actively moving — in that case the movement has to be addressed first.
• How long does crack stitching take? Most residential jobs are two to three working days on site. The mortar and grout continue gaining strength afterwards, reaching full compressive strength at 28 days, but you can use the building normally straight away.
• Will I be able to see the repair afterwards? On brickwork, once the mortar beds are repointed with matched mortar, the repair is very hard to see. On rendered walls it disappears under the made-good render. Nothing sits on the surface — the bars are inside the mortar joints.
• Do I need a structural engineer first? Not always. For a straightforward crack on a building that has stopped moving, we can assess and repair without one. An engineer is needed if the building is still moving, the cracking is severe or widening, a wall is bulging or out of plumb, or an insurer or owners corporation requires an independent assessment. Where a HeliFix manufacturer warranty is required, an engineering design is part of the process.
• How much does crack stitching cost in Melbourne? It depends on the lineal metres of bar required, the number of crack lines, the wall construction, access, and how much repointing or rendering is needed to make good. We give a written quote after a free on-site inspection.
• Is crack stitching cheaper than underpinning? They solve different problems and are often used together. Underpinning addresses a footing that is still moving; crack stitching repairs the masonry that movement has already damaged. If the footing is stable, stitching alone may be all that is needed, which is considerably less disruptive and less expensive than underpinning.
• Can you stitch cracks in rendered walls? Yes. The render is opened along the crack line, the bars are installed into the mortar beds behind, and the render is made good over the repair. Where the existing render is old or already failing, re-rendering the affected elevation gives a better finish than patching.
• Do you provide a certificate for the owners corporation or insurer? Yes. We issue a HeliFix Installation Certificate recording the system installed and the extent of the works, and we provide written inspection and defect reports with photographs for owners corporations, property managers and insurers.

Cracking rarely turns up on its own. We also handle brick repointing where the mortar has perished, lintel replacement where rusting steel is lifting the brickwork, render crack repairs, concrete crack and spalling repairs, leaking balcony repairs and cladding repairs.