Prep is most of a paint job. Cleaning, scraping, patching, sanding and priming decide how the finish looks and how long it lasts. Older Detroit houses need more of it than new ones: plaster cracks, many layers of old paint, oil-based trim paint and stains from old leaks are all common.
Do I need to prime before painting?
You need to prime bare wood, bare drywall, patches, stains, glossy surfaces and big color changes. You do not need primer over clean, sound paint of a similar color.
- Bare wood, new drywall and joint compound: always.
- Water, smoke and tannin stains: a stain-blocking primer.
- Glossy or oil-based paint: a bonding primer after sanding.
- Dark to light color changes: a tinted primer saves a finish coat.
- Chalky or bare masonry: a masonry primer.
Do I need primer if the old paint is in good shape, and can you paint over old paint?
Yes, you can paint over old paint that is clean, dull and firmly attached, and in that case you usually do not need primer. Two finish coats go straight on.
The old paint has to pass three checks. It must not be peeling. It must not be glossy, or it gets sanded first. And it must be clean, with no grease or soot. If any part fails, that part is fixed and spot primed.
Do I need to sand the walls before painting?
Most walls need only a light sand, not a full one. A quick pass with a pole sander knocks off bumps and old roller lint and gives the new coat something to grip.
Sand fully when the old paint is glossy, when there are patches to blend and on all trim and doors. In a home built before 1978, dry sanding old paint can release lead dust, so it is done with lead-safe methods. See our page on lead paint rules.
Do painters fix nail holes, cracks and dents first?
Yes. Filling nail holes, small cracks and dents is a normal part of prep, and it is in our quotes along with sanding, caulking and priming.
Plaster is the local detail. Hairline cracks in plaster are filled and sanded. Cracks that keep coming back are taped. Plaster that has come loose from the lath moves when you press it, and it has to be re-fastened or cut out and patched. That is a repair with its own line on the quote.
How do I paint over a water stain so it does not bleed through?
Fix the leak, let the area dry, then coat the water stain with a stain-blocking primer before you paint. Ordinary latex paint will not hold a water stain back. It comes through again and again, however many coats go on.
Oil-based and shellac-based primers block stains best. Ceilings under bathrooms and around chimneys are the usual places in Detroit houses. If the plaster or drywall is soft, it is replaced, not painted.
Can you paint over smoke stains or pet smells?
Yes, with the right steps. Smoke residue is washed off first, then the surface is sealed with a shellac-based or oil-based stain-blocking primer, then painted. Paint alone will not hold back the yellow film or the smell.
Pet odor usually lives in the floor, the baseboards and the bottom of the walls. Sealing primer on those surfaces helps a great deal, but soaked carpet pad or subfloor has to be dealt with too.
There is mold on my bathroom ceiling. Can it just be painted over?
No. Mold has to be killed and cleaned off before painting, and the damp that feeds it has to be fixed. Paint over live mold peels, and the mold grows back through it.
Light surface mildew on a bathroom ceiling is cleaned, dried, primed with a stain-blocking primer and painted with a mildew-resistant bathroom paint. Then the fan has to do its job. If the mold covers a large area, keeps returning or follows a leak, call a mold specialist. HomeGuide lists small-area mold remediation at $500 to $1,500 nationally.
The paint is peeling to bare wood on my old house. What prep does it need?
Paint that is peeling to bare wood needs scraping back to a firm edge, sanding to feather that edge, primer on every bare spot, caulk at the joints and then two finish coats.
On a Detroit house built before 1978, assume lead until a test says otherwise. That means plastic on the ground, wet scraping or tools with a vacuum attached, no open-flame burning and a careful clean-up. Bare wood should be primed soon after it is exposed, because wood left grey in the sun does not hold paint well.
Why is my paint peeling?
When paint is peeling, the cause is nearly always moisture or poor prep. Water gets behind the film, or the paint was put over dirt, gloss or chalk and never bonded.
- Outside: failed caulk, leaking gutters, bare end grain and wet wood painted too soon.
- Inside: steam, leaks and paint over glossy oil-based enamel.
- Either: too many old layers that have gone brittle and let go together.
Find the cause before repainting, or the new paint will fail in the same place.
Why is paint bubbling or peeling in my kitchen or bathroom?
Paint bubbles and blisters in kitchens and bathrooms because of steam and grease. Moisture gets under the film and pushes it off, most often on the ceiling above the shower and the wall by the stove.
The fix is to scrape and sand the loose paint, wash off grease, prime with a moisture-tolerant primer and repaint with a satin or semi-gloss made for baths and kitchens. A working exhaust fan that vents outdoors is the part that keeps it from coming back.
How do I know if old paint is oil or latex, and can latex go over oil?
Rub the paint with a rag wet with rubbing alcohol. If color comes off on the rag, it is latex. If nothing comes off, it is oil-based.
Latex can go over oil-based paint only after the surface is sanded dull and coated with a bonding primer. Skip that and the new paint peels off in strips. This matters in older Detroit homes, where the trim, doors and often the kitchen and bath walls were painted with oil-based enamel for decades.
Do bare drywall patches need primer?
Yes. Every drywall patch and every area of joint compound needs primer before paint. Bare compound soaks up paint and leaves a dull spot that shows through the finish, which painters call flashing.
Spot prime each patch, and for a wall with many patches prime the whole wall. Then two finish coats give an even sheen from corner to corner.
Call or text (313) 209-8467 for a free estimate. We list the prep for each surface in the written quote.