Every renovation grows. The customer sees the new tiles and wants a niche. You open the wall and find rotten pipework. On a fixed-price job, that's the moment tradespeople dread — because it means talking about more money, mid-job, to someone who thought the price was settled.
It doesn't have to be awkward. The trick is to make change orders a normal, expected step, not a renegotiation.
Why extras feel awkward (and how to defuse it)
The discomfort comes from surprise. If the first time a customer hears "that costs extra" is when you're already covered in dust, it feels like a bait-and-switch — even when it isn't. Defuse it before the job starts:
"Bathrooms sometimes hide surprises behind the old tiles. If we find anything — or if you want to add something — I'll show you the exact cost before I do it, and you decide. No surprises on the final bill."
You've just turned every future change from a confrontation into a promise kept.
The clean change-order routine
- Name it the moment it comes up. "That extra niche is about CHF 280 in labour and tile — want me to add it?"
- Put the number in writing before you start the work. A one-line message is enough: what, why, how much.
- Get a yes on the record. A reply, a signature — anything that isn't just a nod in a noisy bathroom.
- Only then do the work. Never do the extra first and invoice later; that's where disputes are born.
Scripts for the three common cases
Customer wants an addition
Happy to add the underfloor heating — it's CHF [X] all in. Shall I include it? I'll add it to your quote so it's all in one place.
You found hidden damage
Opened the wall and the old pipework's corroded — it needs replacing before I tile, or it'll fail later. That's CHF [X]. I'll send it over so you can approve before I carry on.
Customer asks for a "quick favour"
Of course — that's a small extra, about CHF [X]. I'll pop it on the quote so your final bill matches exactly what we agreed.
Keep the record clean
The reason to log every change — rather than keep it in your head — is that the final invoice should never surprise anyone. When each extra is a written, approved line, the customer already knows the final number before they see it.
This is exactly why tools like Mastro make a change order a one-tap, client-signed step raised from the job itself: the extra gets approved with a signature, the price updates, and both sides have the same record. But the habit matters more than the tool — name it, price it, get a yes, then build it.
Do that and "there's been a change" stops being a difficult conversation and becomes proof that you run a tight, honest job.