Our method, with the numbers you can check

11 steps, in the order they happen on site

1. Find out where the water is actually getting inBefore anything is drilled we work out the path. The crack you can see is often not the entry point — water tracks laterally between a membrane and the concrete and exits at the weakest point, which can be metres from where it started.
2. Rule out the things injection cannot fixBlocked ag lines, failed membranes, condensation, rising damp, leaking services, structural movement. If it is one of those, we say so and stop. This is the step most quotes skip.
3. Scan before drilling where the slab may be post-tensionedGround-penetrating radar and written engineer approval on any suspended or post-tensioned slab. A cut tendon is not a repairable mistake.
4. Set out the packer positionsHoles at 150–400 mm centres, closer where the path is diffuse, and never spaced further apart than the element is thick.
5. Drill at 45 degrees, offset from the crack13 mm holes, offset from the crack line by roughly half the element thickness so the hole intersects the crack at depth, drilled to two-thirds or three-quarters of the thickness. Never straight through — a hole that exits the far face gives the resin somewhere to escape and gives the water a new path.
6. Flush the holes with waterThis does two jobs: it proves the packers are connected to each other through the crack, and it pre-wets the crack, which a water-reactive polyurethane needs in order to cure properly.
7. Fit mechanical packersSteel or alloy packers set into the drilled holes, which take injection pressure. Surface ports glued to the face will not adhere to a wet wall, which is why cheap wet-wall repairs fail.
8. Kill heavy flow firstWhere water is running rather than weeping, a hydraulic plug or oakum goes in first so the resin is not simply washed out before it can react.
9. Inject bottom to topStarting at the lowest packer and moving up only when resin shows at the packer above. That confirms the crack is filling continuously rather than the resin finding one easy path.
10. Leave the packers in for 24 hoursThen cut back, remove them, and make good. Cutting the packers off the same day is how you find out later that the resin had not finished doing its job.
11. Come back and check itRe-inspection after 24–48 hours and after the next real rain event, photographed from the same positions as the before shots so the change is measurable rather than remembered.

Pressure bands

Pressure is chosen for the element, not for the machine. Too little and the resin never reaches the far side of the crack; too much and you widen the crack, blow out mortar beds, or lift a thin slab.

What you get at the end

Photographs, and a written description of what we found and what we did about it. Before and after shots are taken from the same positions so they are genuinely comparable rather than two pictures of roughly the same wall.

We are not going to pretend that is a forensic dossier. Some contractors on large commercial jobs hand over a numbered packer map with resin batch numbers and the volume injected at every point. We do not produce that as standard, and if your engineer or your body corporate requires it, say so at quoting stage so it can be priced in rather than assumed.

What we will always do is come back and check the repair after rain, and tell you straight if it has not held.

Safety, stated plainly

• Confined spaces. Lift pits, tanks and some plant rooms are confined spaces under AS 2865. That means a permit, atmospheric testing, a standby person and a rescue plan — typically $800–$2,000 a day, itemised on the quote rather than hidden in a rate.
• Silica dust. Drilling concrete generates respirable crystalline silica, with a workplace exposure standard of 0.05 mg/m³. On-tool extraction or wet drilling, every time.
• Isocyanates. Polyurethane resins contain them, and sensitisation is permanent. We keep people out of the immediate work area during injection and the safety data sheets are available on request.

What we will not do

We will not inject a designed movement joint, a wall that is still moving, a slab we have not been able to scan, or a crack where the real problem is drainage. We will not quote from a photograph alone when the honest answer is that someone needs to look at it. And we will not tell you a negative-side seal makes a basement permanently dry, because sealing redirects water rather than removing it.