Interior House Painting Guide: Prep, Paint Selection, Techniques & Costs

Preparation

Preparation is 80% of a professional-looking paint job. Rushing prep is the #1 cause of disappointing results.

Clean walls: Wipe down walls with a damp cloth or TSP (trisodium phosphate) solution to remove dust, grease, and grime. Kitchen and bathroom walls need extra attention. Paint won't adhere properly to dirty surfaces.

Repair imperfections: Fill nail holes with lightweight spackle. Repair larger holes and cracks with setting-type joint compound. Sand smooth with 120–150 grit sandpaper. Prime repaired areas with a stain-blocking primer.

Sand glossy surfaces: If painting over semi-gloss or gloss paint, lightly sand with 150–220 grit sandpaper or use a liquid deglosser. This creates "tooth" for the new paint to grip.

Protect surfaces: Remove outlet covers and light switch plates. Apply painter's tape to trim, ceiling edges, and window frames. Use canvas drop cloths on floors (plastic is slippery).

Paint Types

Latex (water-based): The standard for interior walls and ceilings. Easy cleanup (soap and water), low odor, fast drying (1–2 hours between coats), excellent color retention, and low VOC. Use latex for 95% of interior painting.

Acrylic latex: Premium latex with higher acrylic resin content for better adhesion, durability, and coverage. Worth the extra cost ($30–$50/gallon vs $20–$35 for basic latex).

Oil-based (alkyd): Superior adhesion on problem surfaces, self-leveling finish, harder and more durable. Requires mineral spirits for cleanup, strong odor, slow drying (8–24 hours). Use for trim, doors, and cabinets where a hard, smooth finish is desired.

Finishes (Sheens)

Flat/Matte: No shine. Hides imperfections best. Not washable (scuffs and stains are difficult to clean). Best for: ceilings and low-traffic rooms in good condition.

Eggshell: Slight sheen (the most popular finish). Hides imperfections reasonably well while being washable. Best for: living rooms, bedrooms, dining rooms. The go-to for most walls.

Satin: Noticeable sheen. More washable and durable than eggshell. Shows imperfections more. Best for: kitchens, bathrooms, hallways, kids' rooms, and any high-traffic area.

Semi-Gloss: Shiny, hard, very washable. Shows every imperfection. Best for: trim, doors, cabinets, and bathroom/kitchen walls that need frequent cleaning.

Gloss: Highest shine, hardest finish. Shows imperfections dramatically. Best for: front doors, accent furniture, and some trim.

Techniques

Cutting in: Use a 2–2.5-inch angled brush to paint a 2–3 inch band along edges (ceiling line, corners, trim, and around outlets). Cut in one wall at a time, then roll immediately so the brush marks blend with the roller marks while both are still wet.

Rolling: Use a 9-inch roller with a 3/8-inch nap for smooth walls or 1/2-inch nap for textured walls. Load the roller evenly (roll in the paint tray to distribute). Apply in a "W" pattern, then fill in with parallel strokes. Maintain a wet edge — don't let the roller marks dry before blending.

Two coats: Always apply two coats for uniform coverage and color depth, even if the paint claims one-coat coverage. Allow full drying time between coats (check the can — typically 2–4 hours for latex).

Costs

DIY (per room, 12x12): Paint: $30–$80 per gallon (1–2 gallons per room). Supplies: $30–$100 (tape, rollers, brushes, drop cloths). Total: $60–$250 per room.

Professional (per room): $300–$800 per room. Whole house (interior): $2,000–$6,000 for a typical 1,500–2,500 sq ft home.