Short answer
A builder or a carpenter who does subfloor work — and if the house is on stumps, a restumping contractor. The causes are a failed stump, a rotted or split bearer or joist, joists spanning too far after a renovation, or persistent subfloor moisture rotting timber. All four are visible from underneath.
When it is someone else
Calling the wrong trade costs an attendance fee to be told so. These are the cases where this problem belongs to someone other than a Builder.
there is any chance of termites. Soft, springy timber in a subfloor is one of the classic presentations, and a builder replacing the timber without a termite inspection has fixed the symptom.
the subfloor is damp. Leaking drains and water services under houses rot bearers.
What to do before anyone arrives
- Map where it flexes and where it does not. That tells whoever looks which span to examine.
- If there is subfloor access and it is safe, look and photograph: stumps out of plumb or sinking, bearers split, joists rotted at the ends where they sit on the bearer, or fungal growth.
- Check for damp, standing water, blocked vents and anything stored under the house against the timbers.
- Look for termite workings — mud tubing on stumps or piers is unmistakable once you know what it looks like.
What to ask when you book
- Is this a stump, a bearer, a joist, or a span problem?
- Has a termite inspection been done, and should one be?
- Does the repair address why the timber failed, or only replace it?
- Will the floor covering above have to come up?
What changes the price
No dollar figures here: this directory holds no price data and an invented range is worse than none. What follows is what makes one of these jobs cost more than the same job next door, which is the part you can actually use when comparing quotes.
- Subfloor access. A crawl space you can work in versus a 400mm clearance changes everything.
- How much timber is being replaced.
- Whether stumps or piers are involved.
- Whether flooring above has to be lifted and relaid.
What you can do yourself
Is this licensed work?
Structural building work, licensed above a threshold in every state.
There is no national register. Search the licence number with the regulator for the state the work is happening in.
- NSWNSW Fair Tradingbuilders, electricians, plumbers and specialist trades
- VICBuilding and Plumbing Commission, and Energy Safe Victoria for electricalbuilding practitioners and plumbers; electricians are Energy Safe Victoria
- QLDQueensland Building and Construction Commission (QBCC)building and most trade contractor licences
- WABuilding and Energybuilders, electricians, plumbers and gas fitters
- SAConsumer and Business Servicesbuilding work contractors and supervisors
- TASConsumer, Building and Occupational Services (CBOS)building and occupational licences
- ACTAccess Canberraconstruction occupations licensing
- NTNT Government building practitioner registrationbuilding practitioners and electrical workers
Licensing thresholds and certificate requirements differ by state and change with amending regulation, so this page describes the mechanism rather than quoting a figure. The regulator’s own page is the current answer.
Common questions
- Who should I hire for a floor that feels bouncy
- A builder or a carpenter who does subfloor work — and if the house is on stumps, a restumping contractor. The causes are a failed stump, a rotted or split bearer or joist, joists spanning too far after a renovation, or persistent subfloor moisture rotting timber. All four are visible from underneath.
- Is a bouncy floor dangerous?
- It is usually a serviceability problem rather than an imminent collapse, but it is also the presentation of termite damage and of rot, both of which get worse. The distinction between annoying and dangerous is made by looking underneath, which is cheap.
Find a Builder near you
9,049 builders in this directory, ranked on published evidence rather than on advertising.
Who to hire for
- Who to hire for a house that needs underpinningA structural engineer first, then a builder or a specialist underpinning or restumping contractor working to t…
- Who to hire for termites in the houseA licensed pest manager, and do not spray, disturb or break open anything you have found first. Termites aband…
- Who to hire for damp at the bottom of a wallA builder or a damp specialist — but insist on a diagnosis before a treatment. Damp at the base of a wall has …
- Who to hire for water damage to a ceilingFind and fix the source first — roofer, plumber or air conditioning technician depending on the cause — and on…
General information about who does what, not advice about your specific job. Licensing, consumer law and council rules differ by state and change; the regulator for your state is the current source. More guides to hiring a tradesperson.