How to Quote a Job When You Don't Know What's Behind the Wall

You look at a bathroom. The floor is a little soft by the tub. The caulk is black. You can see the problem on top, but you can't see what's under it.

You have to give a number today. The customer wants a number today. And you know that once the wall is open, the job might be twice the size you can see right now.

This is the part of the trade nobody teaches. Quote it too low and you eat the surprise. Quote it with a big cushion and you lose the job to the guy who didn't bother to think about it. There's a way through, and it's mostly about how you write things down before you start.

Say it out loud at the site visit

Don't wait for the quote to bring it up. While you're standing there, tell them plainly.

"I can see the top layer. I can't see under it. If it's just the tile, great. If the subfloor is soft, that costs more, and I won't know until it's open."

Most customers nod and say okay. A few get quiet. That's useful too, because you want to know now which kind of customer you have. The one who gets upset hearing it in the living room will be a lot more upset hearing it with the floor torn out.

Customers rarely mind the unknown. What they mind is being surprised by it. If you say it first, it's information. If you say it after, it feels like a bait and switch, even when it isn't.

Split the quote into what you know and what you don't

The cleanest way is two parts on the same page.

Part one is the work you can see and price. Demo, new tile, new fixtures, whatever it is. That's a normal fixed number.

Part two is the stuff that might be there. List the likely ones for that kind of job, and give each one a price per unit so the customer can do the math if it shows up.

For a bathroom it might look like this:

"Replace damaged subfloor, per sheet, installed: $. Replace damaged framing, per linear foot: $. Mold treatment, if found: priced after inspection."

Those blanks are yours to fill from your own costs. Don't copy a number from anyone else's quote. What matters is that the price is written down before the wall is open, when nobody is stressed.

Now if you find rot, you're not negotiating from scratch. You're pointing at a line on a paper they already signed. That is a much easier conversation than "so, it turns out I need another few thousand."

Use an allowance, not a guess

Some contractors put a number in the quote for hidden stuff and call it an allowance. It works if you're honest about what it is.

Say "this includes an allowance of $__ for repairs to hidden damage. If we use less, you get the difference back on the final invoice. If we need more, I'll show you before I do it."

The "you get the difference back" part is what makes customers trust it. It's their money until it's spent. If you're not willing to give back what you don't use, don't call it an allowance. Call it what it is, which is padding, and expect the customer to figure it out.

The other option is to leave it out of the number entirely and keep it as the line items above. That's usually the better choice when the unknowns are big, because a big allowance makes your total look high next to the other quotes. If you want to think through how to handle that comparison, customer says quote is over budget goes through what to say.

Write the exclusion in plain words

A lot of quotes have a line like "contractor not responsible for unforeseen conditions." It's not wrong, but it's vague, and vague lines get argued over.

Say it in the way you'd say it at the kitchen table:

"This quote covers the work described above. It does not include repair of hidden damage, such as rot, mold, old or unsafe wiring, or structural problems, found after demolition. If we find any, I'll stop, show you, give you a price in writing, and only continue once you approve."

That last sentence is the important one. It tells the customer they stay in control. It also protects you from the worst version of this, which is doing extra work on your own, the customer disputing it, and you having nothing signed.

Stop work and write a change order

When you open the wall and it's bad, take photos right then. Wide shot, close shot, something for scale. Send them to the customer the same day with a short text.

"Opened up the wall behind the tub. There's rot in the bottom plate and two studs. Photos attached. I can fix it for $__ and about a day and a half. I won't start on that until you say yes. Want to call tonight or text?"

Then put the extra work in writing as a change order before you touch it. A text that says "yes go ahead" is better than nothing, but a one-page signed change order is better. How to write a change order has the wording.

Try not to do the extra work first and explain later, even when you're sure the customer will agree. Once you've done it without asking, you've turned a shared problem into a bill, and people fight bills.

When the surprise is bigger than the job

Sometimes what you find changes the whole picture. You opened up a small leak repair and found water damage across a whole wall. Or a floor that needs to be rebuilt, not patched.

At that point, stop and have a real conversation. Tell them what you found, what the options are, and what each costs. It's okay to say "this is bigger than what I quoted, and I understand if you want to think about it or get a second opinion." Then give them a day.

If you're a long way into the job and the cost has blown up, what to do when a job goes over budget covers how to talk through it without making it a fight.

Keep your number valid for a short time

Hidden-condition jobs are the ones where the price can really move, because things get worse the longer a leak keeps running. Put a clear expiry date on the quote, and say that the unit prices hold for the same period. If you're not sure how long to make it, how long should a quote be valid is worth a read.

A few things that help

Take photos before you quote. They help you remember what you saw, and they show the customer what the condition was on day one.

Ask when the house was built, and whether anyone has done work in there. Old houses and past renovations are where most of the surprises live.

Don't pretend to know. "I'm not sure, and here's how we'll handle it" builds more trust than a confident number that turns out wrong.

Collect a deposit even on the open-ended jobs. It holds your date and signals that the customer is serious. How to ask for a deposit has some wording.

And if the customer says "just give me one price, no extras," that's a flag. It's fine to say no to a fixed price when the conditions are unknown. Offer the two-part quote instead and explain why. Some customers will walk, and that's usually the one who would have fought you at the end anyway.

The follow-up is where these quotes die

Quotes with an unknown in them take longer to decide. The customer reads the part about maybe-extra-costs, gets nervous, and goes quiet. A day later it's three days, and you're on another job and the quote slips off your list.

A short text helps: "Hi, any questions about the two-part quote? Happy to walk through the hidden-condition items again if that would help." It lowers the temperature and reminds them you're still there.

The hard part is remembering to send it, especially when you've got a pile of open quotes.

QuoteChaser sends the follow-up texts and emails for you, on a schedule, and lets you know when someone replies. If you'd like that handled, join the QuoteChaser waitlist.