Interior Paint That Actually Lasts: Surface Prep, Primer, and Finish Choices

Mix a TSP (trisodium phosphate) substitute or a few drops of dish soap into warm water. Wipe down all wall surfaces with a damp sponge, working top to bottom. Pay extra attention to areas around light switches, door frames, and baseboards where skin oils and grease accumulate. Allow walls to dry completely — at least two to four hours — before moving on.

Apply spackling compound to nail holes, minor cracks, and dents using a flexible putty knife. Overfill slightly — spackling shrinks as it dries. For cracks wider than about 1/8 inch, apply joint compound in thin layers, letting each layer dry before adding the next. Deep structural cracks or cracks that reappear repeatedly may signal a foundation or framing issue; consult a professional before painting over them.

Once patches are fully dry (refer to the product label for cure time, typically two to four hours for spackling), sand them smooth using 120-grit sandpaper. Follow with 220-grit for a fine finish. Lightly scuff any glossy areas of the wall with 220-grit sandpaper to help primer grip. Wipe all surfaces with a tack cloth or damp microfiber cloth to remove every trace of dust.

Run painter's tape along ceiling edges, baseboards, door and window trim, and outlet covers. Press the tape edge down firmly with a putty knife or your fingernail to prevent paint from bleeding underneath. Lay drop cloths or rosin paper across the floor. Remove outlet and switch covers entirely if possible — tape alone rarely gives a perfectly clean edge.

Apply a coat of interior primer using the same roller-and-brush technique you'll use for the finish coat: cut in along edges with an angled brush first, then roll the field in overlapping 'W' or 'M' patterns to distribute the primer evenly. Choose a drywall primer for new drywall, a stain-blocking primer for water stains or heavy nicotine residue, and a bonding primer for slick or previously glossy surfaces. Allow to dry per the label — typically one to two hours — then lightly sand with 220-grit if the surface feels rough, and wipe clean.

Cut in edges and corners with the angled brush, then roll the walls in sections no larger than about four feet wide. Keep a wet edge — meaning you overlap each new section into the still-wet edge of the previous one — to avoid lap marks. Work in consistent strokes and avoid going back over areas that have started to dry. Apply the paint at a moderate thickness; a coat that is too thick takes longer to cure and is more prone to sagging.

Most interior paints require a minimum of two hours between coats, but allowing four hours or overnight drying reduces the risk of lifting the first coat. Inspect the first coat under raking light (a flashlight held at a low angle) for thin spots or runs. Lightly sand any drips with 220-grit, wipe clean, and apply the second coat using the same technique. Two coats over a properly primed surface is standard; a third coat is occasionally needed over very porous surfaces or dramatic color transitions.