What are the warning signs my house needs reblocking?
The most obvious sign is doors and windows that stick or won't close properly. You might also notice cracks in plaster walls, uneven or sloping floors, gaps appearing under skirting boards, or bouncy floorboards when you walk across them.
Outside, check if the house looks like it's leaning or sagging in one corner. If you can get under the house, look at the stumps directly - crumbling concrete, rotting timber, or stumps that have shifted sideways all mean trouble.
One or two of these signs might not be urgent, but if you're ticking off three or more, you should get someone out to have a look. Read more about reblocking warning signs.
What causes house foundations to fail in Australia?
Timber stumps rot. That's the biggest one. Most houses built before the 1980s in Victoria and Queensland sit on red gum or hardwood stumps, and after 40 to 60 years they start breaking down - especially if the subfloor drainage is poor.
Reactive clay soils are the other big factor. Melbourne, parts of Adelaide, and western Sydney sit on clay that swells when wet and shrinks when dry. That constant movement cracks stumps and shifts footings. Tree roots make it worse by sucking moisture out of the soil unevenly.
Plumbing leaks under the house can also accelerate stump rot without you ever knowing. Learn about foundation risks by region.
How do I tell if a crack is structural or cosmetic?
Hairline cracks less than 2mm wide that run along plaster joins or corners are usually cosmetic - houses move a bit with the seasons and that's normal.
Start paying attention when cracks are wider than 2mm, run diagonally (especially from window or door corners), or appear in brickwork rather than just plaster. Cracks that you can fit a coin into are a red flag.
If a crack is getting wider over time, that's telling you the movement hasn't stopped. Stick a piece of tape across it and check back in a month. If the tape has torn, book an inspection. More on reading wall cracks.
Should I get a professional foundation inspection?
Yes, if you're seeing any of the warning signs - sticking doors, wall cracks, uneven floors. A qualified building inspector or restumping specialist will get under the house, check every stump, measure floor levels, and give you a written report.
Most restumping companies offer free quotes. A full structural engineer's report costs $500 to $1,200 depending on your location, but you'll need one if you're buying an older property or planning renovations.
Don't rely on your own guesswork for foundation issues. What looks minor from inside the house can be serious underneath. Guide to choosing a restumping contractor.
How does foundation damage affect house resale value?
Buyers and their building inspectors will spot foundation problems, and it kills negotiations. Unresolved stumping issues can knock 10% to 20% off your sale price because buyers factor in the cost of repairs plus the hassle.
A pre-sale building inspection that flags reblocking will scare off a lot of buyers entirely. On the other hand, a house that's been freshly reblocked with concrete stumps and has a warranty is a selling point. It shows the house has been looked after.
If you're thinking about selling in the next few years, fixing the stumps now is usually cheaper than the discount you'd cop at auction. How reblocking affects property value.
What is the difference between reblocking and underpinning?
Reblocking (also called restumping) means replacing the stumps that hold your house up. The house gets jacked up, old timber or concrete stumps come out, and new ones go in - usually galvanised steel or concrete. It's the standard fix for houses on stumps that have deteriorated.
Underpinning is different. It strengthens or deepens existing strip footings or slab foundations. You'd need underpinning if your house sits on a concrete slab or strip footings that have cracked or sunk due to soil movement. Underpinning costs more and is a bigger job.
Most older weatherboard and brick veneer homes in Melbourne and Brisbane need reblocking, not underpinning. Reblocking vs underpinning explained.