What crack injection actually costs in Australia

Three quotes, three units, no way to compare them

A linear metre is one metre measured along the length of the crack or joint being treated, regardless of how thick the wall is. It is the most common unit in the trade, and on its own it is close to useless to a buyer, because a rate per linear metre tells you nothing about how many metres there are, how the contractor intends to inject them, or whether they will come back and tidy up afterwards.

The other units in circulation are worse in different ways. Per crack hides the length entirely. Per packer, which is the small fitting installed in a drilled hole so resin can be pumped in, hides the spacing, and wide spacing is exactly how a cheap quote gets cheap. Per square metre only makes sense for curtain injection, which is a different method again, injecting gel into the ground behind a wall rather than into a crack in it. Per job hides everything, unless the scope is written out underneath.

The table below takes one ordinary defect, a 2.4 metre vertical crack in a 200 mm concrete wall at ground level, and prices it five ways using the bands published across the Australian market. The point is not that one number is right. The point is that the same crack legitimately produces answers between roughly $280 and $2,500 depending purely on how the contractor chose to count.

The rate card, item by item

These are the bands the rest of this page is built from. They are indicative South East Queensland metropolitan rates in Australian dollars excluding GST. Residential quotes are normally presented including GST, so a residential figure will read about 10 per cent higher than the same work quoted to a builder or a body corporate.

Two entries need an explicit health warning. The curtain injection rate per square metre is derived from method and material logic rather than from a large body of published Australian rates, so treat it as a starting bracket that a trial panel replaces, not as a price. And the honeycombing and void-filling figures are guides only, because the volume of an interconnected void network is genuinely unknown until injection starts, which is why that work is properly priced by the crew day or against a provisional sum rather than by area.

The minimum that sits under every job and never appears on the quote

There is a floor under this work of roughly $450 to $900 plus GST for a business-hours metropolitan visit, and almost nobody states it. It covers the drive, unloading, setting up an injection pump and hoses, protecting the surrounding surfaces, a minimum block of labour, and packing down again. It exists whether the crack is 400 mm long or 2 metres long, because the set-up is identical either way.

This is why a very short crack does not get cheaper in proportion to its length. A 400 mm crack at $300 per linear metre arithmetically comes to $120. No legitimate contractor will attend for $120, and a contractor who quotes close to it is quoting different work: usually surface ports glued onto the face with a bead of filler over the crack, injected at low pressure, no return visit, and no making good. On a wall with water behind it, the surface seal will not adhere to wet concrete and the ports blow off, so that job is not cheap, it is simply unfinished.

The floor rises predictably. Distance from base adds $1.50 to $3.50 per kilometre or $850 to $1,600 per travel day. A basement with no loading dock access, a car park with a 2.1 metre height limit that will not take the truck, or a site requiring a full induction before anyone touches a tool all push it upward. And because packers must stay in the wall for a minimum of 24 hours before they are cut off, the tidy-up is almost always a second attendance, which means the floor is often paid twice.

The published Australian figures, reconciled

Several price bands circulate publicly in this market and they appear to contradict each other by a factor of ten. Most of the contradiction dissolves once you work out what each figure is actually describing. The table below sets them side by side with the reconciliation.

The single most misleading comparison in the category is dry structural epoxy against wet leak sealing. Epoxy injection into a dry, dormant crack on a long repetitive run, using surface ports at 0.7 to 3.5 bar, with no water present and often no reinstatement, is genuinely cheap work per metre. Leak sealing under hydrostatic pressure using 13 mm mechanical packers at 35 to 140 bar, with a water flush to prove the crack is connected, a 24-hour cure and a return visit to cut back and make good, is not the same job. Quoting one against the other is how buyers end up believing the higher number is a rip-off when it is simply a larger scope.

Everything that moves the number

These are the variables a contractor is actually pricing when they walk your wall. Most of them are invisible from a photograph, which is why a firm price over the phone is either a guess or a quote for a scope narrower than the one you need.

• Element thickness. A 150 mm tilt panel, a 250 mm basement wall and a 400 mm retaining wall are three different jobs. Thickness drives packer length, drilling time and resin volume, and it sets the drilling geometry: holes are offset from the crack line by roughly half the element thickness so that a 45 degree hole meets the crack at mid-depth.
• Water flow rate. Damp staining, a slow weep, a steady trickle and flow under head are four different scopes. Anything gushing usually needs the flow killed first with a fast-gel resin or a hydraulic plug before methodical injection can even begin, and that is an extra operation.
• Packer spacing. Field range is 150 to 400 mm centres, tighter for hairline cracks, wider for open cracks and joints, with a common rule that spacing should not exceed the thickness of the element. A wall quoted at 400 mm centres has roughly half the packers, and half the labour, of the same wall at 200 mm centres.
• Whether it is a crack or a joint. Construction joints, cold joints and the kicker joint where a wall meets the floor slab are wider, connected along their length, take more resin and need closer packers, which is why joint work runs $200 to $500 per linear metre against $150 to $450 for a discrete crack.
• Exposure and reinstatement. You cannot inject what you cannot see. If render, paint, tiles or a wall lining has to come off to expose the crack, that is a separate operation before injection and another one after it. Bare concrete in a plant room finishes at grind-flush. A rendered and painted feature wall does not.
• Access. Ground level and open is the base case. Furniture and fit-out to protect adds time. A scissor lift or knuckle boom adds $450 to $1,600 per day delivered. Confined space adds $800 to $2,000 per day. Soffit work above head height is slower per metre than the same crack at chest height.
• Occupancy. An empty building is cheap. An operating car park needs traffic management at $900 to $2,500 per day and staged closures. A tenanted commercial building often needs night or weekend work, which adds 30 to 100 per cent to labour.
• Quantity and repetition. Productivity is real and measurable: roughly 15 to 30 linear metres of accessible joint per crew per day, 8 to 15 linear metres per day on a kicker joint, and 20 to 50 tie-bolt holes per day. Long repetitive runs on one site pull the rate toward $80 to $200 per linear metre. A single short crack prices as a minimum job, not as a rate.
• Void risk. If there is a drainage layer, a cavity or a washout behind the element, it will accept effectively unlimited resin without ever sealing the face. Disciplined contractors set a hard volume budget per packer, commonly 1 to 2 litres, and stop. Undisciplined ones pump a drum into the ground and bill you for it.
• Distance from base. $1.50 to $3.50 per kilometre, or $850 to $1,600 per travel day. On anything outside the metropolitan area the second visit for cut-back and make good effectively doubles mobilisation, which is why a remote job should be programmed to avoid it.
• Compliance triggers. Scanning and written engineer approval before drilling a post-tensioned slab. A current AS/NZS 4020 certificate for every product touching drinking water, valid for five years. A confined space entry permit for a lift pit, tank or sump. None of these are optional and each of them has a cost.

The four lines that get buried in a lump sum

On commercial and strata jobs these four items regularly account for a third to more than half of the total, and they are the four most likely to be folded silently into a single figure. A committee comparing three lump sums has no way of knowing whether one contractor has included them and another has not, which is exactly how the cheapest quote becomes the most expensive job.

1. Confined space compliance — plus $800 to $2,000 per dayA lift pit, a tank, a sump and many basement plant rooms meet the legal definition of a confined space under AS 2865 and the work health and safety regulations. Entry legally requires a written permit, atmospheric testing before and during entry, a standby person stationed outside who produces no work at all, a means of communication, and a rescue plan with equipment on site. That is an extra body on the crew for the duration plus gas detector hire and calibration, permit administration and lost productivity from entry and exit cycles. A lift pit quote without this line in it is either not being done, or is being done and not disclosed.
2. Traffic management — $900 to $2,500 per dayAny operating car park needs certified controllers and a staged plan so only part of the deck closes at a time. On a car park soffit job this is frequently the single largest line on the quote and it buys no resin whatsoever. It is a compliance and public-safety cost, not a margin grab, and it should appear as its own line so the building can weigh it against closing the deck entirely for a shorter period.
3. After-hours penalty — plus 30 to 100 per cent on labourStandard Australian trade penalty structures run at roughly time-and-a-half for evenings and Saturdays and double time for Sundays and night shifts. Retail, hospitals, hotels and occupied commercial buildings frequently cannot give daytime access, so this is not exotic. It also drags supervision, security escort and after-hours induction costs behind it. Ask whether the quoted price assumes day or night work, because that single assumption can move a car park job by several thousand dollars.
4. Making good — often excluded entirelyMaking good is the tidy-up: cutting the packers off 10 to 20 mm below the surface after a minimum of 24 hours, filling the recesses with a non-shrink hydraulic plug or polymer-modified mortar, grinding flush, and grinding off any cured resin that has bled onto the face. On bare concrete that is usually the finish. Reinstating render, paint, tiles or a wall lining is separate work and is very commonly not included. Get it in writing either way, because cured polyurethane on a wall face has to be ground off before anything will bond to it.

Worked example A — one crack in a house undercroft wall

The three examples that follow are constructed scenarios, not completed jobs. They are here to show how a number is assembled from the rate card above, so that you can do the same arithmetic against a quote you have been handed. No customer, site or job is being described.

Scenario A. A single vertical crack, 2.4 linear metres, in a 200 mm concrete wall at the back of a house undercroft garage on a sloping Brisbane block. Bare concrete, no render, ground level, no fit-out to protect. The crack weeps after rain and dries out in winter. Access is straightforward and the site is inside the metropolitan area.

Worked example B — a car park soffit construction joint

Scenario B. A strata basement car park with water tracking along a construction joint on the underside of the suspended slab, dripping onto bays below. 22 linear metres of joint, treated from a scissor lift, in a car park that must stay partly operational. Building management will only allow night access, so the work is programmed over two nights.

At 15 to 30 linear metres of accessible joint per crew per day, 22 metres is one to two shifts. Two nights are costed here because a night access window is shorter than a working day and the crew loses time to set-up and pack-down at both ends.

This job has one exclusion that must be handled before anyone drills. If the deck is post-tensioned, scanning and written engineer approval are mandatory before a single hole goes in, and that is a separate engagement at $1,200 to $3,500 or more for the engineer's involvement. Cutting a tendon is not a recoverable mistake, and no price on this page contemplates taking that risk.

Worked example C — a lift pit under groundwater

Scenario C. A lift pit in a commercial building holding standing water, with the sump pump cycling constantly. Nine linear metres of kicker joint, which is the joint where the pit wall meets the pit floor slab, plus five form-tie holes weeping in a grid across one wall. There is buffer and hydraulic oil contamination on the pit floor, which has to be removed before anything will bond.

Kicker joint productivity runs at roughly 8 to 15 linear metres per crew per day, so nine metres is one shift of injection. The pit is a confined space, so every one of those shifts carries the compliance loading. Lift isolation and lock-out are done by the lift contractor, never by the injection crew, and their charge is separate and excluded here.

Degreasing is not optional and it is not padding. Oil contamination destroys resin bond and is the single most common cause of a failed lift pit repair, so the pit is dewatered, cleaned and degreased before injection begins.

Five questions that make three quotes comparable

If you are collecting quotes, whether for your own house or on behalf of a committee, these five questions do more to make the numbers comparable than any amount of negotiating. They are deliberately answerable in one line each, and a contractor who cannot answer them quickly has not scoped the job.

1. Mechanical packers or surface ports?A mechanical packer is drilled into the concrete, usually in a 13 mm hole at 45 degrees, and locked in place by tightening a nut that compresses a rubber sleeve against the sides of the hole. It seals inside the wall and takes high pressure. A surface port is glued to the face over the crack with a bead of filler capping the crack between ports. Surface ports are legitimate for low-pressure structural epoxy on dry concrete and for sections too thin to drill safely. On an actively leaking wall they are a known way to waste a day, because the surface seal will not adhere to wet concrete and simply blows off.
2. What packer spacing, and how many packers?Field practice is 150 to 400 mm centres, tighter for hairline cracks and wider for open cracks and joints, with the common rule that spacing should not exceed the thickness of the element. A packer count on the quote turns an abstract rate into something you can actually check against the length of your crack.
3. Which resin are you using, and why that one for this crack?Polyurethane and epoxy are not interchangeable. A flexible polyurethane foam or gel is what stops water in a wet crack that still moves with temperature and load. A rigid epoxy is what bonds a dry, dormant crack back together structurally, and it will not cure properly against running water. A contractor who can name the product and say in one line why it suits your crack has looked at your wall. One who cannot has priced a generic metre.
4. Is making good included, and to what finish?Cutting packers back at 24 hours, plugging, grinding flush and cleaning resin bleed off the face is one scope. Reinstating render, paint, tiles or a lining is another. Ask which one you are buying, and get the answer written on the quote rather than agreed on site.
5. What unit is this built from, and what quantity did you measure?The single most useful line on a quote is the arithmetic: the rate, the quantity, and the loadings shown separately. Two contractors who both write 22 linear metres at a stated rate, plus itemised access, traffic management, after-hours and make good, have produced two comparable quotes. Two lump sums have not.

When the money should not be spent on injection at all

The cheapest injection job is the one that never needed to happen. A meaningful share of enquiries that arrive described as needing injection are actually something else, and sealing the concrete in those situations either achieves nothing or makes the problem worse by raising the water head against the structure. These are the cases where a quote should be declined rather than won.

• Blocked or absent drainage. A crushed or silted ag line, weep holes rendered over during a repaint, a downpipe discharging at the footing, or a driveway falling toward the building. Clearing or correcting these is sometimes the entire fix and costs a fraction of an injection scope. It is also the single most credible thing a specialist can tell you, because it costs them the job.
• A membrane at the end of its life. Injection can seal a defined path through concrete. It cannot restore a membrane that has debonded, split or degraded across a whole deck or planter box. Injection there buys roughly 6 to 18 months. A correct rebuild of a planter box, stripping the soil, replacing the membrane and reinstating the drainage cell and outlet, is typically 1 to 3 weeks of work and is the real number to budget against.
• Condensation misread as a leak. Damp on cold surfaces in still, humid, poorly ventilated spaces with no correlation to rain is very often condensation. The fix is ventilation, dehumidification and insulation. A 48-hour taped plastic sheet test costs nothing and settles it before anyone quotes.
• Rising damp. A tide mark to roughly a metre with salt bloom and perished plaster is capillary moisture climbing through porous masonry, not water through a crack. The treatment is a chemical damp-proof course, a silane or siloxane fluid or cream injected at mortar-joint level. Resin crack injection will not touch it, and the two get confused constantly because both use the word injection.
• Corrosion-driven cracking. Cracking that follows the line of the reinforcement with rust staining, spalling or drummy areas is steel expanding as it corrodes. Sealing over it hides a problem that keeps growing. That is a concrete repair scope with break-out, steel treatment and reinstatement, priced completely differently.
• Broad-area seepage with no defined line. Where water comes through the body of a slab or wall across an area rather than along a line, injection has nothing to grip. The options are negative-side crystalline or cementitious tanking, a drained cavity system, curtain injection behind the wall, or excavation.
• A water tank inside its permissible leakage rate. AS 3735 sets allowable leakage criteria for liquid-retaining concrete structures. Some measured losses sit inside the allowance and need no repair at all. Establishing that costs a test, not a tank refurbishment.
• A crack that is still moving. If the element is still moving, sealing it is a repair you will pay for twice. Fitting crack monitors and reading them over 4 to 12 weeks across a temperature and moisture cycle is cheap insurance against buying the same job again.
• A slab that has sunk rather than leaked. Lifting a settled slab is ground improvement injected into the subgrade beneath the concrete, at $2,500 to $15,000 for typical residential work. It will not stop a drop of water, and it does not address the cause of the settlement either.

Questions we actually get asked

Should a site inspection cost me anything?

There are two different visits and they are priced differently. A quote-only visit, where a contractor looks at an accessible defect and writes a price, is commonly free within the metropolitan area. A diagnostic investigation is not the same thing: moisture readings at marked points, crack monitors installed and read over weeks, water testing, scanning and a written report with recommendations sits at $450 to $1,500. If the water path is genuinely unclear, paying for the investigation is usually cheaper than paying for the wrong repair. An engineer's structural assessment is a separate engagement again, typically $1,200 to $3,500 or more.

Are the bands on this page including or excluding GST?

Excluding GST, unless a line says otherwise. Commercial, builder and body corporate quotes are conventionally presented excluding GST, while residential quotes are normally presented including it. That alone accounts for a 10 per cent difference between two quotes that are otherwise identical, so check which basis each one is written on before comparing them.

Why does a 400 mm crack cost nearly as much as a 2 metre one?

Because most of the cost is not in the length. Travel, unloading, setting up an injection pump and hoses, protecting surrounding surfaces, packing down, and returning at least 24 hours later to cut the packers back and make good are all fixed regardless of how long the crack is. That fixed block is the $450 to $900 site attendance minimum, and it is why very short jobs price as a minimum rather than as a rate per metre.

Do I get charged twice because you have to come back?

You get charged once for a scope that includes two attendances. Packers stay in the wall for a minimum of 24 hours, and longer in cold weather or with a slow-cure product, because the seal has not fully developed before then. Pulling them the same day to finish the job in one visit lets the water straight back in. A quote that includes cut-back and make good has priced that second attendance into it. A quote that does not include make good has quietly left it out.

We are a body corporate and need three comparable quotes. How do we get them?

Issue one written scope and make all three contractors price that scope, rather than each writing their own. The scope needs to state the measured quantity and unit, the packer type and spacing, the finish standard for making good, who provides traffic management and access plant, whether work is in or out of hours, and what verification is expected at handover. Without that, three quotes at three different numbers are simply three different jobs, and the committee has no basis to choose between them.

Does it cost more if we are on the Sunshine Coast or out past Ipswich?

Yes, and it is worth understanding how. Mobilisation outside the metropolitan area runs at roughly $1.50 to $3.50 per kilometre, or $850 to $1,600 per travel day where the distance justifies charging by day. The bigger effect is the return visit: because packers stay in for 24 hours, a regional job that needs a second attendance effectively pays mobilisation twice. Programming the work so cut-back and make good happen on a single trip, or coordinating with other work in the same area, is usually worth more than negotiating the rate.

The quote has a provisional sum on it. Is that a way of leaving the price open?

Sometimes, but on certain scopes it is the honest option. Honeycombing, void filling and curtain injection all involve pumping material into a space whose volume nobody can measure from outside. Honeycombing is a void network, not a line, so a rate per square metre is a rough guide only and the work is properly priced by the crew day at $2,200 to $3,800 or against a provisional sum. Curtain injection should be priced from a trial panel and then charged per point or per kilogram of gel, never as a fixed lump sum on assumption. What matters is that the quote says what triggers the provisional sum, what the rate is, and who authorises spending it.

Where to next

• estimate your own job
• polyurethane crack injection in Brisbane and the Gold Coast
• whether your crack needs polyurethane or epoxy
• fifteen times injection is the wrong spend
• scope it properly before you tender
• run the leak diagnostic