Plastering in Harlem

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.

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.

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.

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.

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).

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.