Bathroom remodels go over budget for predictable reasons, and nearly all of them are plumbing decisions made too late. Here is the checklist we walk through with homeowners before demolition starts.
Before you finalise the layout
Where is the stack, and what slope do you have? Moving a toilet is a floor job — opening the subfloor, rerouting a 3-inch drain, maintaining the fall. Moving a sink within the same wall is minor. Knowing which side of that line your plan falls on before it is drawn is the single biggest saving available.
Slab or crawlspace? It changes everything about what relocating a fixture costs. On a slab, moving a drain means cutting concrete.
Is the existing venting compliant? Frequently not in older homes, and pulling a permit brings it into scope. Better found at survey than at inspection.
Before you choose fixtures
Can your supply feed the shower you want? A rain head plus body sprays plus a hand shower needs a high-flow thermostatic valve and often a larger supply run. This is the one people discover on day one of using a finished bathroom, and by then it is a wall-opening job.
Is there enough hot water? Adding a second primary bath or a wet room can push a house past what its heater delivers. Deal with it as part of the project, not as a disappointment afterwards.
Wall-hung anything? Wall-hung toilets and floating vanities need carriers or blocking, installed at framing stage. There is no retrofitting a carrier.
Bidet seat? Needs a power outlet next to the toilet as well as a supply tee. Add the electrical to the scope now.
Before the waterproofing goes in
Has everything been pressure tested? Every supply line, before anything closes. A leak found now costs nothing; the same leak found after tile costs the tile.
Do the drain assembly and the waterproofing work together? Shower pan drains have to integrate with the membrane. Your plumber and tile setter need to have had that conversation — if they have not, you are the one who finds out.
Are the valve heights right? Measured against the finished floor and finished wall, not the subfloor and studs. It is a common and very visible error.
Worth deciding while it is open
Should the supply be replaced? If your house has polybutylene or galvanised, doing it now costs a fraction of doing it later. The walls are already open, and that is where most of a repipe's cost normally goes.
Accessibility. Grab-bar blocking costs almost nothing to add during framing and is a wall-opening job afterwards. Add it whether or not you need it yet.
Before you pay the final invoice
Permit closed and inspection signed off. Every fixture run and every joint checked under pressure. Warranties registered in your name. Ask for all three.
Planning a bathroom? See how we handle remodel plumbing or request a consultation.