Plasterwork

Getting plaster right in an old building

Confirm what is on the walls now. Buildings constructed before about 1919 were almost always plastered in lime, and any re-plastering should generally match: lime on solid walls, haired lime on lath. Gypsum skim over old lime, or cement-based “renovating” plasters, are the most common modern mistakes and both cause trouble later.

Distinguish plain work from decorative work. Many good lime plasterers do not run cornices, and ornamental fibrous work is a separate workshop trade; check which the firm actually offers.

Ask about mixes and curing. Lime plaster needs the right sand, appropriate hair or fibre, and time between coats; a plasterer who talks about programme pressure and additives may be planning to treat it like gypsum.

For ceilings, ask whether the existing plaster can be consolidated from above rather than pulled down; original lath-and-plaster ceilings are increasingly valued and often saveable.