The coat nobody sees
Paint sticks to what it touches. If it touches grease, soot, chalk, soap film or dust, that's what it bonds to, and it comes away with it later. That's why the first step of almost every good paint job isn't sanding or priming but cleaning. It's also the step most often skipped, because it doesn't look like progress.
Inside: what needs washing
Not every wall needs a scrub, but some surfaces almost always do:
- Kitchen walls and ceilings, which collect a film of cooking grease that paint won't grip.
- Bathroom walls, where soap residue and mildew build up around showers and tubs.
- Trim and doors, especially around handles and light switches, where hands leave oils.
- Walls above heaters and vents, where dust and soot settle.
- Anywhere a smoker lived, where residue can bleed through new paint unless it's cleaned and sealed with the right primer.
Painters typically wash with a degreasing cleaner, rinse with clean water and let the surface dry before patching or priming. Glossy surfaces also need scuffing or a deglosser so the new coat can bite. Our drywall repair and surface preparation guide covers the rest of interior prep.
Outside: washing siding and trim
Exterior walls collect dirt, pollen, mildew and chalk, the powdery residue that older paint sheds as it weathers. Rub a hand along a sunny wall; if it comes away colored, the surface is chalking. New paint over chalk tends to peel.
Exterior washing is usually done with a garden-hose sprayer and a cleaning solution, or with a pressure washer used at a sensible distance and pressure. Too much pressure can drive water into wood, raise the grain and force water behind siding. Whatever the method, the house needs to dry fully before scraping or priming. Ask the painter how long they'll wait.
What's in the rinse water
Harrisonburg Public Utilities reports that in 2025 its water hardness ranged from 12 to 153 mg/L, averaging 67 mg/L; treatment removes some minerals, but calcium and magnesium generally are not removed.
That's useful background for washing. When rinse water dries on a surface, the minerals dissolved in it can stay behind as a faint film or spots, which is why many painters rinse thoroughly and wipe down surfaces that will take a glossy finish. If you notice white spotting on dark trim or glass after washing, that's worth mentioning to the painter before primer goes on.
Washing older paint
Under EPA's Renovation, Repair and Painting Rule, anyone paid to do work that disturbs paint in homes, childcare facilities and preschools built before 1978 must hold RRP certification, firms included, even sole proprietorships, and their workers must be trained in lead-safe work practices.
On a pre-1978 house, aggressive washing can loosen old paint and spread chips. Expect a painter working on such a house to choose gentler methods, put plastic on the ground and collect what comes off. It's reasonable to ask whether the firm holds RRP certification.
How Virginia's regulations describe the specialty
Virginia's Board for Contractors regulations define a Painting and Wallcovering Contracting (PTC) specialty, covering the application of materials common to the painting and decorating industry.
Getting the cleaning into the proposal
Because cleaning is invisible once the paint is on, it should be visible in the proposal. Look for:
- which rooms and surfaces will be washed, and with what;
- how exterior walls will be cleaned, and how long they'll dry;
- how mildew will be treated before primer;
- which primer will seal stains, smoke or grease;
- what the painter will do if chalking or peeling turns up after washing.
The exterior painting and interior painting pages show where cleaning fits in the full sequence, and the pricing guide explains why careful prep shows up in the price.