Partial restumping and stump replacement on the Mornington Peninsula

What partial restumping covers

Partial restumping replaces some of the stumps under a house and relevels the floor on the result. Per stump it is the same work as a full restump: jack, cut out, dig, set, pack. The difference is that it stops where the inspection says the stumps are sound. It still needs a building permit from a private registered building surveyor, because replacing a footing is never exempt as repair under the Commission's practice note BP-01, and it still needs a builder who is registered with the Building and Plumbing Commission, because registration applies to restumping regardless of the value of the work. It is priced per stump, with the permit and the set-up spread over fewer of them, so it only makes sense when the number of good stumps is large and they are not about to follow the bad ones.

It is the wrong job for a house where most of the stumps are the same timber at the same age as the ones that have gone. The full restump page explains when the whole house is the answer.

When a partial job is the right call

• The house was restumped once already. Concrete stumps from a 1980s reblock under the body of a Rosebud holiday house, and a laundry or sleep-out added later on its own timber stumps that have now rotted.
• One wet corner. The bathroom and kitchen side of a Hastings weatherboard where a leaking shower, or a downpipe that was never connected, has rotted half a dozen stumps while the rest of the house stands on dry ground.
• Termite damage in one run. Galleries in a line of stumps near where the nest was found, with the rest clean on inspection. The whole Shire is designated termite prone under regulation 150, so the rest get probed, not assumed.
• A verandah or a chimney base. Verandah posts on short stumps close to the ground, and the heavier stumps under a hearth, fail first and can be done on their own.
• A building report with a short list. A pre-purchase inspection on a Mount Martha house that names four stumps. If the rest of the subfloor passed with photographs, four is the job.
• Sand washed out from one side. On the Nepean dunes the stumps along the side where the base boards failed have tilted, while the stumps under the middle of the house are still plumb in undisturbed sand.

Choosing the replacement stump

The new stump does not have to match the old ones. A redgum stump that has rotted at the ground line after decades in dune sand is replaced with precast concrete or hot-dip galvanised steel, not with more timber. Where the house already sits on concrete, concrete matches and the bearer is bolted down through the cast-in rod. Where the corner being done is the one that keeps moving on Hastings or Bittern clay, an adjustable steel stump there lets it be relevelled later with a spanner rather than another dig. Close to the beach, steel means hot-dip galvanised on a concrete pad that keeps it out of the sand and the salt. The stump types page goes through the trade-off.

How the work runs

1. Inspection. Every stump is probed, not only the ones on the building report, because the cheapest time to find the next rotten one is while the crew is already under the house. The owner gets photographs with the stump count.
2. Quote and contract. The stumps named by position, the type, the depth, relevelling of the affected bearers, ant caps, and what happens if a bearer above a stump is soft. Over $10,000 the Domestic Building Contracts Act 1995 requires a written major domestic building contract; a small partial job often sits under that, and still gets a written quote.
3. Permit. Building permit from a private registered building surveyor. The Shire's lodgement fee was $138.35 in 2025-26 and a property information certificate, which says in writing whether the lot is flood prone, $53.62. The Shire's Asset and Amenity Protection Permit applies at $100,000 of works and a partial restump does not get near it.
4. Replace. Jacks take the load either side, the old stump is cut out, the new hole goes to firm ground, the new stump is set plumb with its ant cap, backfilled and rammed, and the bearer is packed level to the rest of the house.
5. Sign-off. The surveyor inspects and the permit is closed. Keep the final certificate with the house papers; the next building inspector will ask for it.

What the Peninsula adds

The wet side. On the Western Port plains the stumps that fail first are the ones under the wet areas and on the side the block drains toward, so a partial job is usually one side of a house. Doing that side without fixing where the water comes from means doing it again. Regrading the ground under the house and adding vents along the wet side are part of a partial restump here, not an extra. The Cerberus record puts June at 73.5 mm and February at 34.8 mm, so the wet side is wet for a season and dry for a season, which is the cycle that takes timber apart.

The sand side. On the Cups and Rosebud units the failure is often a side of the house, not a corner, where base boards fell off decades ago and wind-blown sand and rain have worked at the stumps along that wall. The replacement stumps go in with the hole shored, and the base boards go back on so the next forty years are different from the last.

The owner who is not there. A partial restump is the job most often done on a holiday house between visits, because the list is short and the crew is in and out in a few days. It is also the job most often done twice, because the list was short only because nobody probed the rest. Insist on the full inspection, with photographs, before agreeing the stump count. The holiday house guide covers what a building report does and does not tell you.

Heritage. A handful of stumps replaced under a timber cottage in the Sorrento Historic Precinct or along Back Beach Road in Portsea changes nothing visible, which is arguably maintenance under the Heritage Overlay. Where the new stumps would show, or the floor height changes, ask the Shire's heritage team before you start.

Whether to relevel the rest while the crew is there

Replacing six stumps brings the bearers over those six back to level. The rest of the floor stays where it is, and on a house that has been settling for fifty years that can leave a step in the hallway between the new line and the old. The choice is whether to relevel the whole floor on the sound stumps while the jacks are already under the house, which adds a day and some packers, or to accept the step and keep the job small. For a house about to be sold the whole-floor relevel is usually worth it, because a building inspector reads a stepped floor as unfinished work. For a holiday house the owner plans to keep, a small step is often lived with. Either way it should be a decision in the quote rather than a surprise on the last day, and the relevelling page explains what packing on sound stumps involves.

Contract and insurance thresholds are worth knowing for a job this size. Over $10,000 the Domestic Building Contracts Act 1995 requires a written major domestic building contract. From 1 July 2026 the builder must hold Home Warranty insurance where the work costs more than $20,000, and before that the figure was $16,000. Many partial restumps sit under one or both lines, so ask the builder which side of each the quote falls and what that means for you if something goes wrong later.