Rules
Part of Before starting interior material choices: a planning guide
Interior material choices: hiring questions
The questions that separate a competent interior contractor from an expensive one, covering certification, dust control, documentation and cleanup standards.
What to take away
- Ask for certification numbers in writing, then check them. A verbal claim is not a credential.
- The dust and containment answer tells you more about a contractor than the portfolio does.
- Insist that the final surface and the products beneath it are both named in the contract.
- Agree in advance what "clean" means at handover, and how it will be verified.
Questions about credentials
Start here, because the answers are checkable. Ask for the business license, the insurance certificate with your project named, and any trade certification relevant to the work. For renovation that disturbs paint in pre-1978 housing, the firm needs the specific federal certification for that work, not a general contractor license.
Ask a second question that most homeowners skip: who is actually on site each day, and are they employees or subcontractors? Certification attaches to firms and to trained individuals, so a certified company sending an uncertified crew is a real risk.
Then ask what happens if testing finds a hazard. A contractor who says "we would stop and bring in an abatement firm" is describing the correct answer. One who says "we handle that ourselves" needs to prove it with paperwork.
Questions about dust, containment and lead
Lead work is the area where a bad answer is most expensive. Paint disturbed by sanding, scraping or demolition produces dust, and EPA sets the hazard standards and clearance levels for lead in paint, dust and soil that define when a surface counts as a hazard and when a cleaned area passes.
Ask specifically: how will you contain the work area, will you use HEPA vacuums, how will waste leave the house, and will a clearance test be performed at the end? CDC's summary of lead in paint and how exposure happens at home is worth reading before this conversation so you can tell a serious answer from a reassuring one.
If children under six or anyone pregnant lives in the house, say so explicitly and ask how the schedule will protect them. Relocation during dusty phases is a normal answer, not an alarmist one.
Questions about products and documentation
| Ask this | A good answer looks like | A bad answer looks like |
|---|---|---|
| Which adhesive and primer will you use? | Named products with data sheets | "Whatever we normally use" |
| Who tests subfloor moisture? | Named party, method, threshold | "It will be fine" |
| What is the waste plan? | Container size, haul dates, what gets salvaged | "We take it away" |
| What documentation do I get? | Photos, receipts, test results, care sheets | A one-line invoice |
Put the winning answers into the contract as named products. "Low VOC adhesive" in a contract means whatever is in the van on the day.
Questions about the finish line
Define completion before work starts. Ask what surfaces will be cleaned, whether HVAC filters will be replaced, whether ducts were sealed during the work, and what the punch list process is. Ask how long the contractor guarantees their labor as distinct from the manufacturer's material warranty, and get both in writing.
Set your shortlist against the planning steps in our pre-project guide to interior materials, and read the answers alongside the failures that recur on interior jobs. A contractor whose answers anticipate those failures is usually the one who has seen them.
Common questions
Should I hire trades directly or use one contractor? Direct hiring saves margin and costs you the coordination. On any job with more than two trades, one responsible party is usually worth the markup.
How many quotes are enough? Three, priced against the same written scope. Quotes against different scopes are not comparable at all.
Is the lowest bid a red flag? Not automatically, but check what is missing. Low bids usually exclude preparation, disposal or the installation system.
Who is responsible if a hazard is found mid-job? Whoever the contract says. Settle it in writing before demolition, including who pays for the delay.
