Most paint failures are prep failures. Patching, sanding, caulking and priming are part of our jobs and our quotes. This page explains what each step does and when it is needed.
Do I need to prime before painting?
You need to prime bare surfaces, stains, patches, glossy or oil-based paint and big color changes. You do not need a full prime coat on clean, sound, flat paint in a similar color.
- Bare wood, bare plaster and new drywall: always prime.
- Patches and filled holes: spot prime.
- Water, smoke or tannin stains: stain-blocking primer.
- Glossy or oil-based paint: sand and use a bonding primer.
- Chalky exterior surfaces: wash, then prime if chalk remains.
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 stuck, and it does not need a full coat of primer. Wash it, sand any gloss, spot prime repairs and apply two finish coats.
Paint-and-primer-in-one products are thicker paints. They help with coverage, but they do not replace a true primer on bare wood, stains or slick surfaces.
Do I need to sand the walls before painting?
Walls need a light sand, not a heavy one. A quick pass with a pole sander knocks down bumps, roller lint and old drips, and dulls any sheen so new paint grips.
Trim, doors and cabinets need more thorough sanding because they are glossier. In a house built before 1978, dry sanding old paint can release lead dust, so lead-safe methods apply.
Do painters fix nail holes, cracks and dents first?
Yes. Filling nail holes, small cracks and dents is normal prep and is included in our quotes. Nail pops are reset and filled so they do not come back.
Plaster cracks are common in older homes here. Hairline cracks are opened slightly, filled and sanded. Cracks that keep returning, or plaster that has come loose from the lath, need a proper repair and are priced as such.
How do I paint over a water stain so it does not bleed through?
Seal a water stain with a stain-blocking primer, oil or shellac based, before you paint. Regular wall paint will not hold it back. The brown ring comes through again within days.
Fix the leak first and let the area dry. Water stains on ceilings below bathrooms and under old roofs and box gutters are everyday finds in Pittsburgh houses.
Can you paint over smoke stains or pet smells?
Yes, with the right primer. Smoke residue is washed off as far as possible, then the walls and ceilings are sealed with a stain and odor blocking primer before finish paint.
Ordinary paint does not seal nicotine. It bleeds through yellow. Pet odor in walls can be sealed the same way, but odor in carpet, pad or subfloor has to be dealt with at the source.
There is mold on the bathroom ceiling. Can it just be painted over?
No. Mold must be killed and cleaned off before painting, or it grows back through the new paint. After cleaning, the ceiling is primed with a stain-blocking primer and painted with a moisture-resistant bathroom paint.
The real fix is drier air: a working exhaust fan that vents outside and is run during and after showers. Many older bathrooms here have only a window. If mold covers a large area or keeps returning, have the cause found. Nationally, small-area mold remediation is listed at $500 to $1,500.
Paint is peeling to bare wood on my old house. What prep does it need?
Bare wood needs scraping, sanding, priming and caulking before paint. All loose paint is scraped off, the edges are sanded smooth, and the bare wood is primed with an exterior primer made for it.
On a house built before 1978, assume the old paint has lead unless a test says otherwise. Scraping then has to follow lead-safe rules: plastic on the ground, no open-flame burning, no uncontained power sanding, and careful clean-up. Wood that has sat bare and grey should be sanded to fresh wood so primer can bond.
Why is my paint peeling?
When paint is peeling, the cause is almost always moisture or poor prep. Water gets behind the paint film, or the paint was put over dirt, chalk, gloss or damp wood and never bonded.
- Outside: leaking gutters, open joints, wood close to the ground, damp north walls.
- Inside: steam, leaks, or paint applied over glossy or dirty surfaces.
- Latex paint applied straight over old oil-based paint without primer.
- Too many old layers that have become brittle.
In our climate, freezing and thawing make it worse. Water in the wood expands as it freezes and pushes the paint off.
Why is paint bubbling or peeling in my kitchen or bathroom?
Paint bubbles and blisters in kitchens and bathrooms because of steam and moisture. Water vapor gets behind the paint, or the paint was applied over a damp or greasy surface.
The cure is to scrape and sand the failed areas, clean off soap film and grease, prime, and repaint with a paint made for humid rooms. Then improve the ventilation, or it will come back.
How do I know if old paint is oil-based 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 only after the surface is sanded dull and coated with a bonding primer. Without that step the latex peels off in sheets. Old trim and doors in Pittsburgh houses are very often oil-based, so we test before we paint.
Do bare drywall patches need primer?
Yes. Drywall patches and joint compound must be primed before painting. Bare compound soaks up paint differently from the wall around it, and the patch shows as a dull spot.
We spot prime every patch. Where a wall has many repairs, priming the whole wall gives a more even finish.
Questions about your own walls? Call or text (412) 668-1875 for a free estimate.