Plastering in Bau

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.

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).

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.

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.

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.

Skim coat handles minor waviness and hairline cracks at a fraction of the cost. Hollow-sounding, damp-damaged or badly out-of-plumb plaster needs hacking and re-plastering — a skim over failing plaster peels within a year or two.