Cracks and movement
Cracks and footing movement in Canberra homes
Many cracks are cosmetic. Some mean part of the house is moving. We find the cause, tell you whether it matters and set out what to do next, with no repair to sell you afterwards.
- From $1,090 + GST ($1,199 inc GST) for an inspection and report
- Fixed quote in under 20 minutes on average, during business hours
- 359 mm, then 913 mm of rain at Canberra Airport in 2019 and 2021
Prefer to talk? Call 02 6189 9876
Or email info@canberrastructuralengineers.com.au
Monday to Friday, 8:00am to 5:00pm
- Engineering onlyWe never sell the repair or the build.
- From $1,090 + GST($1,199 inc GST), confirmed before we start.
- Fixed quote in under 20 minutes on averageDuring business hours, Monday to Friday.
- Canberra and the Queanbeyan sideEvery district, plus Queanbeyan, Jerrabomberra and Googong.
In short
A crack and footing movement report in Canberra costs from $1,090 + GST ($1,199 inc GST). An engineer visits, inspects the cracks and the house, and gives you a written report with the findings, the likely cause and what to do next. If clear photos are enough, a desktop review is $390 + GST ($429 inc GST). The same prices apply across Canberra, Queanbeyan, Jerrabomberra and Googong.
- On-site report
- From $1,090 + GST ($1,199 inc GST)
- Desktop review of photos
- From $390 + GST ($429 inc GST), no visit
- You receive
- The findings, the likely cause and what to do next
- Causes we separate
- Clay movement, leaks and drainage, trees, fill
- Quote
- Fixed, in under 20 minutes on average, during business hours
- Area
- Every Canberra district, plus Queanbeyan, Jerrabomberra and Googong
Are the cracks in my walls serious?
Often not. Width is one guide, but the pattern, the location and whether the crack is still growing matter as much.
AS 2870, the Australian standard for house slabs and footings, groups wall damage into categories by crack width. Hairline and fine cracks sit at the bottom of the scale. From about 5 mm, with doors and windows sticking, the standard calls the damage moderate.
Width alone can mislead. A 2 mm crack that doubles over a summer says more than a wider one that hasn't moved in years. Signs that the house, not only the plaster, is moving:
- Stepped cracks following the mortar joints in brickwork
- Cracks running from the corners of doors and windows
- Doors that stick or won't latch, then free up again
- Gaps opening at the cornice, skirting or between a wall and the ceiling
- Floors that slope towards one corner
To track a crack, mark its ends in pencil with the date and photograph it beside a ruler. Our guide to cracks in walls in Canberra covers the common patterns in more detail.
- Cat 0Negligible< 0.1 mm
Hairline cracks.
- Cat 1Very slight< 1 mm
Fine cracks which do not need repair.
- Cat 2Slight< 5 mm
Cracks noticeable but easily filled. Doors and windows stick slightly.
- Cat 3Moderate5–15 mm
Cracks can be repaired; some wall may need replacing. Doors and windows stick, service pipes can fracture, weathertightness often impaired.
- Cat 4Severe15–25 mm
Extensive repair: sections of wall broken out and replaced. Frames distort, walls lean or bulge, some loss of bearing in beams.
- Cat 5Very severe> 25 mm
Major repair, partial or complete rebuilding. Beams lose bearing, walls lean badly and need shoring. Danger of instability.
What's included in a crack and footing movement report?
An engineer visits, inspects the cracks and the house, and gives you a written report with the findings, the likely cause and what to do next.
| Option | What you get, and when it fits | From, ex GST | Inc GST |
|---|---|---|---|
| Desktop review of photos | We review the photos and any reports you send and give written advice. No site visit. Fits one or two cracks you can photograph clearly, or a repair quote you want checked. | $390 + GST | $429 |
| Crack and footing movement report | An engineer visits, inspects the cracks and the house, and gives a written report with the findings, the likely cause and what to do next. Fits cracks in several rooms, cracks that keep growing, or a decision about repairs. | $1,090 + GST | $1,199 |
From prices for a typical house, confirmed in your fixed quote before anything is booked. See all our prices.
What we need from you
- Photos of the cracks, close up and from further back
- When you noticed them, and whether they open and close with the seasons
- Anything nearby: large trees, a leak, new paving or recent building work
- The suburb and roughly when the house was built
What you get back
A report you can act on: what is moving, the likely reason, and whether it needs repair, monitoring or nothing at all. If the repair is building work, you take the report to the builder or repairer you choose.
Want the whole house checked, not only the cracks? A structural inspection and report covers it at the same price.
Why do Canberra houses crack and move?
Because the clay under many homes shrinks when it dries and swells when it wets, and Canberra's rainfall swings hard from year to year.
Canberra Airport recorded 358.6 mm of rain in 2019, the driest year since 1982. In 2021 it recorded 912.6 mm. Clay that dries out and then soaks like that changes volume, and the footings sitting on it move with it.
Drainage near the footings matters more on some ground than others. The Williamsdale soil landscape, under most Canberra suburbs, has widespread seasonal waterlogging, and the soils along its drainage lines are usually poorly drained and sodic. Sodic means high in sodium: these soils soften and break down when they stay wet.
The Burra landscape, on footslopes in Tuggeranong, Woden and Weston Creek, has sodic subsoils and widespread seasonal waterlogging too.
On ground like this, a leaking downpipe, a garden bed built up against a wall or water ponding beside a footing can do real harm. Fixing the water is often part of the answer.
Check the water first
- Downpipes connected, and not emptying beside the wall
- Gutters clear, so they don't overflow onto the footing line
- Garden beds and paving sloping away from the house
- No leaking taps, hot water units or pipes near the cracks
Rainfall: Bureau of Meteorology annual climate summaries. Our guide to Canberra soils and footings explains the ground in more depth.
What's causing the movement?
Usually one of four things, and often more than one. The report separates them, because each needs a different fix.
What moves a house? Four common causes
- Trees and roots draw moisture from the soil near a footing, so clay under that side shrinks.
- Reactive clay swells when wet and shrinks when dry, moving footings with the seasons.
- Leaking pipes or poor drainage soak and soften the ground under part of the house.
- Poorly compacted fill keeps settling under a footing long after the house is built.
Seasonal clay movement
Footings rise and fall as the clay under them wets and dries. Cracks tend to open in dry spells and partly close in wet ones.
Leaking pipes and drains
A leak soaks the clay under one part of the house, so that part swells or softens while the rest doesn't. The leak has to be fixed before anything else.
Trees
Roots draw water from the clay near a footing, so that side shrinks. If the tree is protected, even on the neighbour's block, excavating more than 100 mm deep over 4 m² or more of its tree protection zone is prohibited groundwork under the Urban Forest Act 2023 unless approved. See protected trees and building.
Fill
Poorly compacted fill keeps settling long after the house is built. Published site classification reports for new-estate blocks warn that uncontrolled fill means "Class P conditions", the AS 2870 class for problem sites.
Should you rely on a free assessment from a repair company?
Get one if you like, but know who's paying for it. Firms that sell underpinning or resin injection often assess for free because the assessment leads to the sale.
That doesn't make their advice wrong. It means nobody independent has checked it before you commit.
We're engineers only. We don't sell, carry out or recommend repairs, so our report reads the same whether the answer is new footings or a plumber.
Sometimes the right fix is underpinning. Sometimes it's a leak repair, better drainage or watching the crack through a wet season and a dry one. Underpinning usually needs building approval; your certifier confirms.
Already have a quote?
Our underpinning second opinion checks whether the cause has been found and whether the scope fits, from $390 + GST ($429 inc GST).
Is your house less than 6 years old?
Then the builder's statutory warranty may cover structural defects, so get the cause documented early.
In the ACT, structural elements carry a 6-year warranty from completion, and that includes the weatherproofing of external walls and the roof. The warranties apply to residential work costing $12,000 or more, not to owner-builder work, and they pass to later owners.
A building defect report sets out what's wrong in a form you can take to your builder.
What happens next?
Three steps, and you know the price before anything is booked. Same prices from Belconnen to Queanbeyan.
Send photos of the cracks
Use the form at the top of the page, or email info@canberrastructuralengineers.com.au. Add up to 5 photos.
Get a fixed quote
We reply with a fixed quote in under 20 minutes on average, during business hours. If photos are enough, we say so and quote a desktop review.
Inspection and report
An engineer inspects the cracks and the house, then sends your written report with the cause and what to do next.
Often needed alongside a crack report
Every service is quoted at a fixed price before we start. Send photos or plans and we reply in under 20 minutes on average, during business hours.
Underpinning: independent second opinion
Quoted for underpinning or resin injection? An engineer checks whether the movement calls for it and whether the scope fits, with no repair to sell.
$390 + GST($429 inc GST) See the service
Structural inspection & report
An engineer inspects the house and gives you a written report: what was found, the likely cause and what to do next.
$1,090 + GST($1,199 inc GST) See the service
Cracks in walls in Canberra: when to worry
Most cracks in Canberra homes are cosmetic, but some point to footing movement. How to read width and pattern, what the soils and rainfall swings do, and what to record before you call.
Read the guideQuestions about cracks
Something else on your mind? Call 02 6189 9876, email info@canberrastructuralengineers.com.au or send photos for a fixed quote.
When should I worry about cracks in walls and ceilings?
When they grow, reopen after patching or come with other signs. Sticking doors, sloping floors and gaps at the cornice or skirting point to movement. A hairline crack that stays the same is usually cosmetic.
How much does a structural engineer cost to check cracks in Canberra?
From $1,090 + GST ($1,199 inc GST) for an inspection and written report. If clear photos answer the question, a desktop review is $390 + GST ($429 inc GST). Your quote is fixed before we start.
Is it house settling or subsidence?
The words matter less than the cause. Clay that shrinks and swells, a leaking pipe, a tree and poorly compacted fill can all show up as cracks, and each needs a different fix. The report's job is to find which one it is.
Do cracks in brick walls always mean a footing problem?
No. Walls also crack where different materials meet and where a wall changes direction or height. The pattern, the width and whether the crack is still moving show whether the footings are involved.
Can you check a repair quote I've already been given?
Yes. A desktop second opinion on an underpinning or resin injection quote is $390 + GST ($429 inc GST). Send the quote, any report that came with it and your photos.