Wall Finishes: Steps to Paint
Golden rule (sequence after MEP)
MEP rough-in & pressure tests → Substrate prep → Render (plaster) → Dry/cure → Base/level skim → Finish skim → Primer → Final paint (washable).
Cutting or re-ordering steps leads to cracks, telegraphing joints, poor adhesion, and visible waves under light.
Step-by-step
1) Substrate preparation
- Remove loose material/dust, de-grease, treat mould/salts, fix cracks (V-cut + mesh/filler).
- Check plane with 2 m straightedge; mark high/low areas.
- Prime per substrate (masonry, concrete, board) to control suction.
2) Render (tencuială) — establishes plane & hardness
- Type: cement–lime or gypsum (dry interiors).
- Apply: scratch/brown coats to bring walls within flatness tolerance (target SR2 ≤5 mm/2 m).
- Reinforce: corner beads; mesh at openings/mixed substrates.
- Cure: protect from rapid drying; respect curing time (cement) or set (gypsum).
3) Base/level skim (glet grosier)
- Purpose: correct minor undulations, joints, and pores left by render.
- Materials: gypsum or cement-based (wet areas/exteriors).
- Application: 1–2 coats, 1–3 mm each; feather out wide.
- Check: re-measure flatness; spot fill as needed.
4) Finish skim (glet de finisaj)
- Purpose: achieve paint-ready smoothness (SR1 ≤3 mm/2 m).
- Materials: fine gypsum or polymer ready-mix for best glide/low pinholes.
- Application: 1–2 thin coats; light sand with dust extraction.
- Lighting check: rake light along the wall to catch defects; repair now, not after paint.
5) Primer & paint (lavabil)
- Primer/sealer: match to skim (controls suction, improves adhesion).
- Paint: washable acrylic/silicone for interiors; moisture-resistant in kitchens/baths.
- Coats: test patch + 2 finish coats; maintain wet edge to avoid flashing.
Quality checkpoints (hold points)
- After MEP rough-in: pressure tests passed; all chases closed before render.
- After render: flatness SR2, beads straight, no hollow spots; moisture within limits.
- After base skim: flatness trending to SR1; no ridges/drag lines.
- Before paint: dust-free, primed uniformly; sample patch approved under site lighting.
Materials by zone (quick guide)
- Dry rooms: gypsum render/skim or polymer ready-mix finish.
- Wet rooms & kitchens: cementitious base (render/base skim) + flexible finish skim; waterproof where specified before tiling/paint.
- Mixed substrates (masonry + board): mesh bridging at transitions to prevent cracking.
Common mistakes & how to avoid
- Skipping primer: causes peeling/pinholes → always prime per manufacturer.
- Too thick in one pass: shrinkage cracks → multiple thin coats.
- Poor curing (cement): dusting/weak surface → control airflow/temperature; mist as specified.
- No mesh over chases/transitions: hairline cracks → embed alkali-resistant mesh.
- Painting over damp: blistering/alkali burn → moisture test; wait to spec.
Tolerances & moisture (typical)
- Flatness targets: Render SR2 (≤5 mm/2 m) → Finish SR1 (≤3 mm/2 m).
- Moisture before paint: per product data; cement bases must be visibly dry and within RH limits; avoid forced drying.
Cost & programme (percentages only; baseline = render only, no skims/paint = 0%)
- Add base skim (grosier) to achieve plane: +10–25%
- Add finish skim to reach SR1: +10–20% (saves rework at paint stage −5–15%)
- Primer + 2 coats washable paint: +10–25%
- Polymer ready-mix (instead of gypsum) for premium finish: +20–60% materials, but −10–25% labor on sanding/defects
- Skipping base skim on wavy render (rework risk): +15–35% downstream (extra paint, patches, client snags)
- Programme impact: full sequence adds +10–25% time vs “render → paint”, but reduces post-handover snags −25–50%
Coordination tips
- Finish all MEP chasing & boxes before render; photograph routes.
- Set bead lines from finished floor/ceiling levels; keep reveals square for clean window lines.
- Use raking light QA after each stage; fix now, not later.
- Protect finished walls from other trades (corner guards, board protection).
Short FAQ
- Can I paint directly over render? Not recommended for high-quality finish; use base + finish skim for SR1, then prime/paint.
- Gypsum in bathrooms? Only in dry zones; use cement-based in wet/steam areas under waterproofing/tiles.
- Why is primer essential? It equalizes suction and locks dust, giving even sheen and stronger adhesion.
Want this as a printable site checklist (boxes to tick) or a compact compare card (materials by room, % costs, tolerances)? I can format it for your website style.
