Plastering in California

A skim coat is touch-dry in a day but needs roughly a week to fully dry before painting; full re-plaster can take several weeks depending on thickness, ventilation and season. Paint too early and you trap moisture, causing peeling. Use a mist coat (diluted emulsion) first.

No — plaster over damp fails within months. The moisture source (rising damp, leaking gutter, condensation) must be fixed first, then damaged plaster cut back and replaced, sometimes with a salt-resistant renovation plaster. Any plasterer who skips the cause is selling you a repeat job.

Fine crazing usually means the plaster dried too fast (heat, draughts) and is cosmetic — fill and paint. Straight-line cracks along boards or above doors indicate movement at joints. Wide or recurring cracks are worth a builder's inspection before redecorating.

Skimming is a thin 2-3 mm finish coat applied over existing plaster or plasterboard to give a smooth paintable surface. Full plastering means building up base (browning/bonding) coats plus a finish coat, needed when old plaster is blown, damp-damaged or removed back to brick.

Rendering is exterior plastering with cement- or silicone-based mixes to protect and finish outside walls; plastering refers to interior walls with gypsum or cement finishes. Many plasterers do both, but exterior render is priced and scheduled differently (weather-dependent).

Yes, if the substrate is sound — plasterers key the surface and use bonding agents. But blown (hollow-sounding), crumbling, or damp-stained plaster must come off first. A good plasterer taps the walls during the quote to check; be wary of anyone who doesn't.

Plastering is usually priced per square metre or per room. A skim coat over existing sound walls is the cheapest job; full re-plastering (hacking off old plaster and applying new base and finish coats) costs two to three times more, and exterior rendering is priced separately.

Sometimes, but true plaster repair (reattaching keys, veneer coats) is a specialty. Drywall contractors often just cut out plaster and board over, which changes wall depth and trim reveals. For historic homes, seek a plaster specialist.