How much does plastering cost?

A skim is a thin finish coat over what is already there — existing plaster that is sound but tired, or fresh plasterboard. It is quicker and much cheaper, and it is what most people actually need.

A full re-plaster means hacking the old plaster off back to the brick, then building up base coats before skimming. It is necessary when the existing plaster is blown, damp-damaged or crumbling, and it costs roughly double because of the removal, waste and extra coats.

How do you tell? Tap the wall. A hollow sound over an area means the plaster has lost its bond to the brick behind — that is blown plaster, and skimming over it will crack. Solid sound throughout usually means a skim will hold.

Any plasterer worth using will do this check before quoting and tell you which you need. Be cautious of anyone quoting for a skim without touching the walls.

If a wall is damp, plastering over it will fail. The moisture comes back through, the new plaster blows, and you pay twice.

Find the cause before booking a plasterer: a leaking gutter, failed pointing, a bridged damp-proof course, a plumbing leak, or condensation from poor ventilation. Fixing the source is a different trade from plastering, and it comes first.

After a leak is fixed, walls need genuine drying time — often weeks, not days — before new plaster goes on. A plasterer who is willing to skim a visibly damp wall without asking why it is damp is telling you something about their standards.

If salts have come through from long-term damp, the wall may need a specialist render or a salt-retardant additive rather than ordinary plaster.

Fresh plaster is not ready to paint. It needs to dry fully — commonly three to seven days for a skim, longer for a full re-plaster, longer again in winter or in a cold room. Rushing this is the most common cause of paint failing on new plaster.

You can see it happen: the plaster goes from dark brown to a pale, even pink. Patches still darker are still wet.

When it is dry, the first coat is a mist coat — emulsion thinned with water, roughly 70:30 — which soaks in and gives the finish coats something to key to. Skipping the mist coat and going straight on with full-strength paint is why new plaster sometimes peels in sheets later.

Do not force-dry with heaters. It dries the surface faster than the depth and causes cracking.

Skim rather than re-plaster wherever the existing surface is sound. Tap the walls and find out before assuming the worst.

Clear the room and lift the floor covering yourself. Plastering is messy, and paying a plasterer to move furniture is expensive labour.

Do several rooms at once. Mixing, setting up and cleaning down happens per visit, not per room.

Book the plasterer and the decorator with realistic time between them. Paying a decorator to wait, or worse to paint too early, costs more than the gap would have.

Get at least three quotes and ask each to explain skim versus re-plaster for your walls. If the answers differ, that difference is worth understanding before you choose on price.