Pricing a bathroom renovation: the lines everyone forgets

Bathrooms are small rooms with big line counts. Six or seven trades pass through four square metres in a fortnight, and the profit disappears not in the sanitaryware but in the twenty small lines nobody wrote down. Here is the full anatomy of a bathroom price, forgotten lines included.

Why small rooms get mispriced

The instinct on a bathroom is to price the visible things: suite, tiles, fitting. But a renovation is really three jobs stacked on top of each other. There is a demolition job (strip-out, disposal, discovery of whatever the last installer hid). There is a services job (moving water, waste, and electrics to where the new layout wants them). And there is a finishing job (the part the client thinks they are buying). Quotes fail when they price the third job and wave at the first two.

Density is the other trap. In a room this size, every trade waits on another: the electrician cannot second-fix until the tiler is done, the tiler waits on the tanker, the tanker on the boarder. Half-day visits multiply, and each one carries travel and setup time that a rate-per-metre mindset never captures.

The forgotten lines, room by room

Run down this list against your last bathroom quote and count the misses:

Sanitaryware: PC sums and the delivery trap

Clients choose their own suites, so the supply cost belongs in a PC sum: a stated allowance, adjusted at cost against receipts, with your fitting labour priced firm alongside it. The full method is in our guide to provisional sums and PC sums. Two practical warnings from the tools. First, client-ordered goods arrive late, damaged or incomplete far more often than merchant orders, and a missing basin waste can stall a finished room for a week; say in the quote that delays from client-supplied goods are chargeable or at least reprogrammed. Second, check what the allowance actually covers: a £600 "toilet and basin" allowance that excludes the flush plate, frame, and brassware is a £300 surprise waiting to happen.

Labour: price the sequence, not the square metres

A typical full renovation of a family bathroom runs somewhere in the region of eight to twelve working days across the trades: a day or two of strip-out, two to three days of first fix plumbing and electrics, a day of boarding and tanking, two to four days of tiling depending on coverage and tile size, then second fix, glass, sealant and decoration. Your local day rates times that honest programme is a far better labour estimate than any rate per square metre, precisely because the room is small: setup, protection and waiting dominate in a way per-metre rates never see.

Build the programme, then price the programme. If the client's tile choice moves from ceramic 300s to large-format porcelain, the tiling days change, and your quote should visibly change with them. An itemised bill makes that conversation easy; a lump sum makes it a squabble.

Put it together as a bill, not a guess

A defensible bathroom quote ends up as thirty to fifty lines: strip-out and disposal, each services move, boarding, tanking, tiling by area with sundries, the PC sums, each trade's labour by the day, protection, and making good. That sounds laborious, and by hand it is, which is why so many bathroom prices are one hopeful number. QS Quoter generates that full line-by-line bill from a plain description of the job at your own rates, including the tanking, trims and boxing-in most quotes forget, and you edit any line before it goes out. The client gets a clean priced breakdown; you keep a private copy showing every rate. The forgotten lines are the margin, and this is the cheapest way to stop forgetting them.