Restumping advice

My house is sinking: what to check first

Published 17 September 2026

Something has caught your attention. Maybe a door that used to swing shut on its own now needs a shove, or a shove is now too much and it won’t latch at all. Maybe you rolled something across the lounge room floor and watched it roll further than it should have. Before you search “foundation repair near me” and start collecting quotes, it’s worth spending twenty minutes doing your own triage — because what you find changes both how urgently you need to act and who you need to call.

This isn’t a substitute for a proper inspection. It’s the difference between calling someone with “the floor in the back bedroom drops about 15mm over two metres, and it’s gotten worse in the last three months” versus calling someone with “the house feels a bit sinky.” The first gets you a useful quote. The second gets you a guess.

Start with the floor, not the walls

Cracks get the attention because they’re visible on a wall you look at every day, but a wall crack is a downstream symptom. The floor — or the slab underneath it — is where the actual movement is happening, and it’s easier to measure objectively than a crack is.

If you have a suspended timber floor, put a marble or a round pen down in the middle of a few rooms and watch what it does. A floor with genuine movement will roll consistently toward the same low point. Do it in more than one room; a single sloped room can be original construction on an older house, while several rooms sloping toward the same corner of the house is a pattern.

If you have a concrete slab, the marble test is less reliable on tiles or a levelled floor finish, so use a spirit level across a few metres, or check whether a ball or a full water glass placed near an external wall behaves differently to one placed in the centre of the house.

Either way, write down what you find: which room, which direction, roughly how much fall over how much distance, and the date. A phone note with today’s date is enough. You are creating the “before” that lets you or an engineer answer the only question that actually matters later: is this getting worse?

Photograph and measure, don’t just look

A photo without a reference point is hard to compare later. Before you take a single picture:

• Put something for scale in frame — a tape measure, a ruler, even a coin — next to any crack or gap you’re photographing.
• Check the gap between skirting boards and the floor, and between skirting and the wall, in every room that concerns you. A widening gap at floor level is one of the more reliable early signs of a timber floor moving.
• Test every door and window that’s ever given you trouble, not just the one you noticed today. Note which corner catches — top, bottom, one side — because the position tells a trade more than “it sticks” does.
• If you have subfloor access, look underneath. Photograph any stump that looks visibly out of plumb, any soft or crumbling timber at ground level, and any standing water or obviously damp ground. Note whether it’s near a downpipe, a tap, or a low point that would collect rain regardless of any leak.
• If you’re on a slab, walk the perimeter outside and photograph where downpipes discharge, whether garden beds are banked up against the brickwork, and any external paving that now slopes back toward the house rather than away from it.

None of this requires getting under the house if you’re not comfortable doing so, or if access is genuinely tight. The exterior checks alone — downpipes, garden beds, paving falls — catch a meaningful share of the moisture-driven cases we see, and they cost nothing to look at.

The one question that sorts most cases: does it come back?

This is the single most useful thing you can establish, and it takes a season rather than an afternoon. Mark today’s measurements with a date. Come back in three months, ideally spanning a change of season — summer into autumn, or winter into spring — and measure the same spots the same way.

If the numbers are the same, or the gap has partly closed again, you’re most likely looking at seasonal ground movement: reactive clay swelling and shrinking under a slab, or a stump system flexing slightly with moisture rather than actually failing. That’s a real thing worth understanding — see our guide to reactive clay in Melbourne’s west — but it’s rarely a same-week emergency.

If the gap has widened, or the slope has measurably increased, that’s one-directional movement, and it doesn’t correct itself. This is when a proper assessment stops being optional.

Two different problems hide behind the same word

“Sinking” describes what you feel, not what’s actually happening underneath you, and the cause splits cleanly along construction type. If your floor sounds hollow underneath and there’s a subfloor space you could crawl into, a sinking feeling usually means failed or settling stumps — the timber has rotted at ground level, or an early concrete stump has settled into a footing that was never deep enough. That’s a job for restumping, and it behaves exactly like the seasonal test above predicts: once a stump goes, it only ever gets worse.

If your home is brick veneer on a solid concrete slab, there’s nothing under the floor to fail — the ground itself is moving, either swelling seasonally under reactive clay, settling permanently where a leaking pipe has washed soil away, or consolidating where the house sits on fill that hasn’t finished compacting. That’s underpinning territory, and which of those three mechanisms applies changes the fix completely. For the fuller breakdown of which service applies to which construction type, our guide to restumping vs underpinning covers the distinction in depth.

Settlement — the permanent, one-way kind rather than seasonal heave — is the dominant pattern in a specific set of suburbs, and it’s worth knowing whether yours is one of them. In Reservoir and Preston, it’s typically sound concrete stumps sitting on footings that were only ever poured to a 1950s budget, settling evenly rather than dropping in one spot. In Cranbourne, the lower-lying ground toward the old swamp margins consolidates under load in a slow, steady way that never recovers with the seasons — a genuinely different mechanism to the reactive clay a few streets away. Pakenham shows the same pattern on its creek-flat estates, where alluvial soil settles rather than swells.

What to do with what you’ve found

If your measurements are stable, your doors are behaving the same as they were a year ago, and nothing you’ve photographed looks urgent, you can reasonably book an assessment at a normal pace rather than treating it as a crisis. If the numbers have moved, or you’ve found visible rot, a leaning stump, standing water under the house, or a jammed door or window, that’s worth getting looked at properly rather than waiting for the next seasonal check.

---

Bring what you’ve measured and photographed to a free on-site assessment — it saves time on the visit and it means the answer you get is based on your actual numbers, not a guess made standing in the driveway.

Common questions

How do I check if my floor is actually sloping, without paying for an inspection?

The cheapest test is a marble or a round pen on the floorboards or tiles — set it down in several rooms and see whether it rolls, and which direction. For something more precise, a $20 spirit level laid across a doorway threshold, or a long straight edge across a hallway, will show a fall a marble might miss on carpet. Whatever you use, write down the room, the direction of fall and roughly how many millimetres over how many metres, with the date. That record is the thing an inspector or engineer actually wants to see, not just a description of 'it feels wonky'.

Is it urgent if my house is sinking, or can it wait until it's convenient?

Most cases can wait a few weeks for a proper assessment; a smaller number can't. Treat it as urgent if a door or window has jammed shut where it used to close fine, if you can see daylight through a wall crack, if the change has happened over weeks rather than months, or if you can see standing water, a leaning stump or visibly rotten timber under the house. Everything else — a slope that's been there for years and isn't changing, mild seasonal door-sticking — is worth documenting and booking in normally rather than treating as an emergency.

My floor has always sloped a bit. When does 'it's always been like that' stop being a safe assumption?

When you can no longer verify it's true. 'Always been like that' is a reasonable thing to believe about a house you've lived in for fifteen years and watched not change. It's a much weaker assumption on a house you bought two years ago, because you have no record of what it looked like before you owned it. If you're relying on that assumption, get a baseline now — levels, photos, marked doors — so that in a year's time you're comparing measurements instead of memory.

← All foundation advice