How to price a bathroom renovation without losing money

Bathrooms look small on paper and eat money in practice. Several trades share one tight room, everything has to happen in the right order, and the problems you can’t see until the old lining comes off are your problem once the price is signed. Most losses on bathroom jobs aren’t caused by charging too little per hour. They come from leaving things out of the price.

This guide walks through a way of pricing that builds the number up from the actual work, so the figure you send covers what the job really costs you, plus a profit you chose on purpose.

Step 1: Scope it properly before you price anything

You can’t price what you haven’t seen. On the site visit, record more than the floor size:

• Room dimensions, ceiling height, and every wall that gets tiled or lined (height as well as length)
• Window and door positions, and anything that has to move
• Where the waste, water supply and power are now, and where the client wants them
• What’s under the floor (timber or concrete) and how you’ll get to the plumbing
• Signs of existing leaks: soft floor, swollen skirting, stains on the ceiling below, mould behind the vanity
• Access: stairs, parking, how far you’ll carry materials and rubbish
• What the client is supplying, if anything (tiles, tapware, vanity)

Take photos of everything. They save a second trip and settle arguments later about what was there on day one.

Step 2: Build the labour up stage by stage

Don’t guess one number for “the bathroom”. Break the job into the stages it actually happens in and put hours against each one:

1. Strip-out and rubbish removal
2. Framing and floor repairs
3. Plumbing rough-in
4. Electrical rough-in
5. Linings (wet-area board)
6. Waterproofing, including cure time
7. Tiling and grouting
8. Fit-off: vanity, toilet, tapware, shower screen, accessories
9. Final clean and handover

Then add the hours people forget: travel each day, setting up and packing down, getting materials, and the extra visits caused by waiting. Membranes need to cure, adhesives need to set, and other trades need to finish before you can go back in. A job with four short return visits costs more than the same hours done in one block, so count the visits as well as the hours.

Step 3: Do a proper materials take-off

Work out quantities from your measurements rather than eyeballing them, and price each line from your supplier, not from memory.

• Tiles: add a waste allowance. Around 10% is a common starting point for a straight lay, and more for diagonal or herringbone patterns, lots of cuts, or large-format tiles. Check the batch numbers match so the shade is consistent.
• Waterproofing: primer, membrane, reinforcing tape or bandage, and puddle flanges. Price the full system from one manufacturer.
• Consumables: adhesive, grout, silicone, screws, sealant, blades, sanding pads, plastic sheeting and tape. They’re small items that add up to real money on every job.
• Rubbish: skip hire or tip fees.

If the client is supplying fittings, say in writing that you’re not responsible for missing parts or delivery delays, and price the extra time it takes to deal with them.

Step 4: Get subcontractor prices in writing

If you’re bringing in a plumber, electrician or tiler, get their price in writing before you send yours, with what’s included and what isn’t. A phone “should be about…” is not a price. Use licensed trades wherever your local rules require them.

Step 5: Know what an hour of your time really costs

Your hourly rate has to cover far more than your wage. Add up a year of running costs: vehicle, fuel, insurance, tools and repairs, phone, software, accounting, levies and licences, plus what you want to earn. Then divide by the hours you can actually bill. That is not 52 weeks of 40 hours. Take out holidays, sick days, quoting, admin and travel.

Step 6: Allow for what you can’t see

Old bathrooms hide rotten floor joists, illegal plumbing and wiring, and leaks that have been going for years. You have three honest ways to handle this:

• An allowance in the price for likely problems, stated as a line item
• A provisional sum: a set amount for a known risk that is adjusted up or down once it’s opened up
• A clear exclusion saying hidden damage is extra, priced as a variation if found

What doesn’t work is ignoring the risk and hoping. Whichever you choose, write it down so the client knows before work starts.

Step 7: Add margin, and know the difference from markup

Markup and margin are not the same thing, and mixing them up is one of the most common ways trade businesses underprice.

	Markup method	Margin method
Job cost	$10,000	$10,000
Add	20% markup on cost	Price so 20% of the price is profit
Price (before tax)	$12,000	$12,500
Profit	$2,000	$2,500
Actual margin	16.7%	20%

To hit a target margin, divide your cost by (1 minus the margin). For a 20% margin that’s cost ÷ 0.8. The numbers in this table are only an example. Your own costs and target margin will be different.

Step 8: Put it all in writing

The price is only half the quote. Spell out:

• What’s included, stage by stage
• What’s excluded (painting, ceiling repairs, moving power points, and so on)
• Prime cost (PC) sums for fittings the client hasn’t chosen yet
• How variations are priced and approved
• Payment stages and the deposit
• How long the price is valid for

A clear quote wins more work, and it is your protection when something changes halfway through.

Common mistakes that cost money

• Pricing labour as one lump instead of stage by stage
• Forgetting cure times and return visits
• No waste allowance on tiles
• Leaving out consumables, rubbish removal and travel
• Treating markup as margin
• No allowance or exclusion for hidden damage
• Letting extras happen without a written variation

A quick checklist before you send the price

• Have you seen and photographed everything?
• Is every stage priced in hours, including return visits?
• Is every material on the list, with waste?
• Do you have written prices from every subcontractor?
• Does your rate cover your real running costs?
• Is the unknown handled with an allowance, a provisional sum or an exclusion?
• Have you added margin, not just markup?
• Are inclusions, exclusions, payment stages and validity written down?

Get those right and a bathroom becomes one of the most profitable jobs you do, instead of the one you lose sleep over.