Replastering a Room: What Actually Happens

Before the plasterer arrives

The room needs to be clear. Plaster splashes, dust travels, and moving furniture mid-job costs time you are paying for. Carpets are usually lifted or fully protected, and anything staying in the room gets sheeted.

This is also the point to finalise anything that lives in the wall: sockets moving, new lighting circuits, a TV point, extractor ducting or a radiator relocating. All of it is cheap now and expensive next week.

Preparation and background

Old plaster comes off where it has failed, and the exposed background is assessed. Different backgrounds need different treatment: engineering brick and dense block need a bonding agent, old lime-plastered walls need a compatible approach, and dusty surfaces need stabilising.

Beads go on at external corners and around openings, and any electrical boxes are set to the correct depth for the finished plaster thickness.

Floating and setting

A backing coat is applied and ruled flat, then allowed to firm up. The finish coat goes on over it in two thin passes and is trowelled several times as it sets, which is the part that produces a flat, polished surface.

• A typical room is one to two days of plastering for a skim over sound walls
• A full strip and float takes longer and creates significantly more waste
• Ceilings usually go first, then walls, so splashes are covered
• The plasterer needs power, water and reasonable warmth on site

Drying and decorating

New plaster is dark and wet when finished and gradually turns a uniform pale pink or cream as it dries. Painting before that colour is even traps moisture and causes peeling.

Ventilate rather than blast heat at it. Rapid forced drying causes cracking and can leave the surface hard-set with a soft core.

The first coat should be a thinned mist coat of matt emulsion so it soaks into the surface and provides a key for the full coats.