Bathroom Renovation Plumbing Checklist: What to Sort Out Before Tiling

Once the tiler starts, your plumbing decisions are locked in. Chase a wall open after tiling to move a pipe or add an access panel and you’re paying to re-tile as well as re-plumb. Most of the bathroom renovation problems we get called out for after the fact — a shower that never had proper fall, a toilet moved six centimetres from where the waste pipe actually sits, a geyser with no way to reach the drip tray — trace back to plumbing decisions that should have been settled before the first tile went up. Here’s what to sort out first.

Confirm the Waste and Supply Layout Before You Move Anything

Moving a basin, toilet or shower a metre “for a better layout” sounds simple on a floor plan and is rarely simple under the floor. Waste pipes rely on fall (a consistent downward slope to the main drain) — move a toilet away from the existing soil pipe and you may need to break up the slab to re-route it, not just extend it. Before any tiling quote is finalised, get a plumber to confirm which fixtures can move on the existing waste runs and which would need slab work. This is the single biggest cost driver in East Rand bathroom renovations we see going over budget, and it’s entirely avoidable if it’s checked before demolition.

Rough-In Plumbing Happens Before Waterproofing, Not After

All supply and waste pipework inside the walls and floor needs to be roughed in, pressure tested, and signed off before the waterproofing membrane goes down — and definitely before tiling. Pipes chased into a wall after waterproofing is applied means cutting through the membrane, which is exactly how slow leaks inside walls start showing up as damp patches or mould a year or two later with no obvious source. If your contractor’s schedule has tiling starting before all plumbing rough-in is finished, that sequence is wrong.

Pressure Test Before Anything Gets Covered

Every new or altered pipe run should be pressure tested while it’s still visible — before wall board, waterproofing or tiling covers it. A slow leak in a newly plumbed shower or basin line is cheap to find and fix when the pipe is exposed, and expensive once it’s behind tile. We won’t sign off rough-in plumbing without a pressure test, and if your renovation isn’t including one, ask why.

Plan Access to the Geyser and Any Shut-Off Valves

Bathroom renovations frequently box in or tile over the geyser cupboard, drip tray, or isolation valves to make the space look tidier — and then six months later there’s a leak or a service call and nobody can get to the fitting without breaking tile. Decide where access panels go before tiling starts, not after something fails. A PIRB-compliant installation requires the drip tray and relief valve discharge to remain visibly accessible for inspection — tiling over them isn’t just inconvenient, it can affect your compliance certificate.

Extraction Fan Ducting Needs to Be Routed Before the Ceiling Closes

Not strictly plumbing, but it’s decided at the same stage and gets missed constantly: bathroom extractor fan ducting needs a route to outside air (through the roof or an external wall) planned before the ceiling is closed up. A fan that just vents into the roof space pushes moisture into your ceiling cavity instead of outside, which over time causes exactly the kind of hidden damp and timber damage a waterproofed bathroom is supposed to prevent.

Get a PIRB Compliance Certificate for Any Altered Plumbing Work

If the renovation moves or adds any water or waste connections — not just cosmetic fixture swaps — that work should be signed off with a PIRB compliance certificate once it’s complete. This matters most if you’re renovating ahead of selling: a buyer’s conveyancer will ask for it, and retrofitting compliance after tiling and fittings are in means potentially opening up finished work to verify what’s actually behind the wall.