What to expect: the underpinning repair process step by step
From the first crack you notice through engineer's report, quotes, the works themselves and monitoring afterwards, so you know what a proper job looks like.
If an engineer has confirmed your footings are moving, the repair itself follows a fairly predictable path. Knowing the sequence helps you see where a corner is being cut and keeps the project in a sensible order, with diagnosis before design and design before digging.
1. Assessment and monitoring
It starts with a structural engineer inspecting the property, and often installing simple crack monitors or level surveys to measure how much the structure is moving and in which direction over weeks or months. This distinguishes active movement that needs intervention from old, dormant cracks that only need cosmetic repair, and it identifies the cause, which drives everything that follows.
2. Diagnosis, design and quotes
Once the cause is understood, the engineer specifies the fix, which might be as simple as repairing a leaking pipe and regrading drainage, or as involved as full underpinning to a set depth. With that design in hand you invite quotes from remedial or underpinning contractors, all working from the same specification so you can compare them fairly on method, pier count, load and inclusions.
3. The works
Underpinning is carried out in carefully sequenced sections so the house is never left unsupported. Depending on the method, that means excavating and concreting pits in stages, winding in screw piles and transferring load onto brackets, or injecting expanding resin through small tubes to compact soil and re-level the structure. Good contractors keep the site tidy, protect finishes, and work to the engineer's design and hold points. Most residential jobs take days to a couple of weeks, longer for extensive or difficult sites.
4. Reinstatement and monitoring
After the structural work, cracks are repaired and finishes made good, ideally after a short settling period so patched cracks do not simply reopen. The engineer may certify the completed underpinning, which is valuable documentation if you sell. Continued light monitoring confirms the movement has stopped. Throughout, keep every report, quote, certificate and photo together, because that record is both your protection and an asset at resale.
Common questions
How long does underpinning take?
Most residential underpinning jobs take from a few days to a couple of weeks of on-site work, with resin injection often at the faster end and staged mass concrete underpinning at the slower end. Complex or large sites take longer. The assessment and design phase beforehand can add several weeks, especially if movement is monitored across a season.
Do I have to move out during underpinning?
Usually not. Underpinning is carried out in sequenced sections so the house stays supported and habitable, and work is generally external or in the sub-floor. Your engineer or contractor will tell you if any part of the job requires temporary changes, but most homeowners stay in the house throughout.
Sources
- CSIRO, Foundation Maintenance and Footing Performance: A Homeowner's Guide (BTF-18)
- Standards Australia, AS 2870 Residential slabs and footings
Prices are indicative guides only, not quotes. Confirm cost and method with a licensed contractor after an inspection.
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