Paint Preparation + Priming Guide
Why this matters
90% of paint job quality comes from preparation. Skip the prep + you get peeling within months; do prep right + paint lasts decades. The painter who masters prep + primer delivers customer satisfaction + premium pricing. This is the field card.
Surface preparation steps
1. Clean: dust, grease, mildew, contamination.
2. Repair: holes, cracks, damaged areas.
3. Sand: scuff sand for adhesion; smooth defects.
4. Mask: protect non-paint surfaces.
5. Prime: as needed for substrate + condition.
6. Final wipe-down: tack cloth OR damp rag.
7. Apply paint: at proper conditions + technique.
Cleaning by substrate
Drywall (new): dust with dry brush; no water (damages paper). Drywall (existing): wipe with damp cloth; address stains. Wood (interior): dust + damp wipe; fresh wood, wipe with mineral spirits. Wood (exterior weathered): pressure wash + scrape loose paint + sand smooth. Metal: degrease (TSP OR mineral spirits); remove rust; etch if needed. Concrete/masonry: pressure wash; remove efflorescence; muriatic acid etch if needed. Previously painted: TSP wash + sand per condition. Mildewed: bleach 1:4 solution + rinse thoroughly + dry.
Common cleaning products
TSP (trisodium phosphate): heavy-duty cleaner; mix per label.
TSP substitute: less aggressive; phosphate-free.
Mineral spirits: degreasing + wax removal.
Acetone: aggressive solvent; some plastics damaged.
Vinegar diluted: mild cleaning; mineral deposits.
Pressure washer: 1,500 - 3,000 PSI typical exterior; don't blast paint into damage.
Surface repair
Drywall holes: small (< 1") spackling + sand; medium (1 - 6") patch kit OR mesh tape + joint compound; large (> 6") section replacement + tape + mud. Wood holes/cracks: wood filler OR putty (latex OR oil). Plaster crack: V-cut + skim with joint compound OR plaster. Metal pitting + rust: wire brush + rust converter + primer. Concrete crack: caulk for hairline; epoxy injection for structural. Stucco: scratch coat + brown coat + finish coat.
Sanding for paint adhesion
Existing glossy paint: 220 - 320 grit to scuff sand (key for adhesion).
Bare wood: 100 → 150 → 220 grit progression.
Drywall: 220 grit screen (gentle; don't tear paper).
Repaired areas: feather edges 6 - 12" beyond patch for invisible transition.
Between paint coats: 220 - 320 grit to knock down nibs.
Sanding aid: tack cloth OR damp rag for final dust removal.
Mask + protect
Painter's tape: blue (28-day) OR FrogTape (paint-sealing edge).
Apply firmly: press edge to prevent paint bleed.
Don't leave up past spec: bonds; lifts substrate when removed.
Plastic sheeting: cover furniture + floors.
Drop cloths: floor protection; canvas (preferred) OR plastic (cheap; slick).
Light fixtures + hardware: remove OR bag + tape.
Door knobs / handles: bag with painter's tape.
Common primers + uses
PVA: new drywall primer; specific for drywall. Acrylic latex: general-purpose interior + exterior. Oil-based/alkyd: covers stains + tannins; great adhesion; thinner cleanup. Shellac (BIN, White Pigmented Shellac): blocks tough stains (smoke, water, mildew, marker); fast-dry; alcohol cleanup. Bonding (XIM, Zinsser Cover Stain): laminate, glossy, slick surfaces. Stain-blocking (Kilz, Bullseye 1-2-3): water stains, tannins, smoke odors. Masonry (Loxon): concrete + brick; alkaline-resistant. Metal primer: galvanized OR steel-specific. Rust-converting: chemically converts rust to inert. Etching: galvanized + plastic for adhesion.
When to prime
New drywall: PVA primer always; 1 coat. New wood: oil-based (better grain seal) OR acrylic latex (faster). Existing paint, repaired: spot-prime patches OR all if changing dramatically. Glossy (cabinet, trim): bonding primer OR scuff sand + standard. Stained: shellac OR stain-blocking. Smoke/fire damage: shellac primer required. Light-over-dark: 1 - 2 coats primer OR tinted. Bare metal: metal-specific primer. Concrete/masonry: masonry primer.
Caulking
Latex acrylic caulk: most interior; paintable; easy cleanup.
Acrylic latex with silicone: durable + paintable + flexible.
100% silicone: kitchen + bath; NOT paintable.
Polyurethane: exterior; durable; paintable; harder to apply.
Apply before primer: typically; primer over caulk.
Tool with finger (wet with water for latex; soapy water for silicone): smooth finish.
Allow proper cure before painting.
Paint type + primer compatibility
Latex paint over latex primer: most common.
Latex paint over oil primer: OK; latex sticks to oil-based primer.
Oil paint over latex primer: less common; specific oil-bonding primer.
Oil paint over oil primer: traditional; long-lasting.
Latex over old oil paint (without prep): peels. Sand to scuff + bonding primer.
Exterior prep
Power wash (1,500 - 3,000 PSI; remove dirt + chalk). Scrape loose paint (hand scraper + putty knife). Feather edges (sand smooth transition). Spot prime (bare wood + repairs + stains). Caulk (window + door frames; trim joints; expansion joints). Mildew kill (bleach solution + rinse before paint). Don't paint over chalking (rinse off OR sand smooth).
Common prep mistakes
Skipping clean (paint won't adhere to dirty surface). Painting over caulk (caulk shows through; needs primer). Not feathering repair edges (visible bumps). Painting glossy without scuff sand (peels). Skipping primer on new drywall (paint seeps unevenly; visible roller marks). Painting in too-cold OR too-hot conditions (per paint can spec). Painting humid surface (moisture in paint; poor finish).
Paint job timeline
Bedroom (12 × 14 ft) walls + trim: prep 1 - 2 hr; prime (if needed) 1 hr; 2 coats 3 - 5 hr; cleanup 30 min - total 5 - 8 hr. Kitchen + cabinet refinishing: prep + clean 4 - 8 hr; sand box + doors 4 - 8 hr; prime 2 - 3 hr; 2 - 3 coats 6 - 10 hr; reassemble 2 hr - total 1 - 3 days. Whole house interior (1,500 sq ft): prep + repair 1 - 2 days; prime 1 day; 2 coats 2 - 3 days - total 4 - 6 days.
Truck stock
Painter's tape (multiple widths), FrogTape, drop cloths (canvas + plastic), spackling compound, joint compound, mesh tape, putty knives (1", 3", 5"), scrapers, sandpaper assortment (80, 120, 220 grit), sanding sponges, dust mask, tack cloths, plastic sheeting, primer (PVA + acrylic latex), caulk (latex paintable), caulking gun, mineral spirits, denatured alcohol (shellac cleanup), TSP cleaner.
The single most-impactful paint habit is the EXTRA HOUR ON PREP rather than rushing to paint. Customer sees the finished color; you know the prep determines durability + appearance. 2 hours of additional sanding + cleaning + caulking + priming = 5 - 10 year longevity vs 1 - 2 years for skipped-prep job. Customer becomes loyal because the job actually lasts. Charge for prep + deliver on the longevity promise. Painters who skip prep get callbacks; painters who do prep right get referrals.
References
- Manufacturer technical data (Sherwin-Williams, Benjamin Moore, Behr, PPG)
- Painting + Decorating Contractors of America (PDCA)
- ASTM standards for paint testing
- Manuall internal: PPE Selection, Common Construction Adhesives