The assumptions hiding in your contractor's quote

Every quote you've ever received was priced on a stack of assumptions the contractor never wrote down. Not because they're hiding anything — because after enough years, those assumptions feel too obvious to state. The trouble is that your assumptions and theirs were formed in two different heads, and they don't always match. The quote looks like agreement. Underneath, it can be two people quietly picturing different projects at the same price.

The assumptions that cost the most

Who supplies what. The most common collision in residential work. You assumed the quote included the appliances; the contractor assumed you'd buy them and they'd install. You assumed the vanity was in there; it was “by others.” Nobody lied. The line just lived in two different heads. Every major item — appliances, fixtures, vanities, flooring, hardware — needs a clear answer: supplied by whom, installed by whom.

The condition behind the walls. A price assumes a starting point: that the framing is sound, the subfloor is level, the wiring is to a workable standard. The contractor priced the project they expect to find. If reality differs — and in older homes it often does — the assumption breaks and the cost moves. You can't eliminate this, but you can ask what condition the price assumes, so you know which surprises are already covered and which aren't.

What “standard” means. “Standard fixtures,” “standard finish,” “builder-grade.” The contractor has a specific product and price tier in mind. You have a picture in your head from a showroom. These are rarely the same tier. This is the assumption that hides inside allowances — the placeholder is set at the contractor's idea of standard, not yours.

Site access and logistics. Can the contractor park? Is there a place to stage materials? Third-floor walk-up or ground-level? These shape labour cost, and they're usually assumed silently based on a single site visit — or no visit at all.

The tell: a quote with no assumptions stated

Here's the counterintuitive part. A quote that lists its assumptions and exclusions plainly is the safer document, even though it looks more conditional. It was written by someone who has been burned by the gap between two heads and decided to close it on paper. A clean, assumption-free quote isn't a quote without assumptions — it's a quote where the assumptions are all still invisible, waiting. See why a good exclusions list is a green flag.

How to surface the assumptions before you sign

• For every major item, ask: supplied by whom, installed by whom? Appliances, fixtures, flooring, hardware, vanities. Get each answer onto the quote.
• Ask what condition the price assumes behind the walls and under the floor — and what happens to the price if it's worse.
• Pin down “standard.” Ask for the actual product or price tier behind any “standard” or “builder-grade” line, and compare it to what you actually want.
• Confirm the contractor has seen the real site, not just photos, before trusting the labour number.
• Ask directly: “What are you assuming about my project that isn't written here?” An experienced contractor can list them. That list is the most valuable paragraph you'll get.

It's the same root cause as everything in why renovations go over budget: the number on the quote is rarely the problem. The unspoken context around it is.