Plastering and skimming

The question is really about what is behind the surface. Tap the wall. A dull, hollow sound over a wide area means the old plaster has parted from the block, and skimming over it only buys a year or two before it cracks along the same lines. In that case it comes off, the wall is cleaned down, and it is floated and skimmed again. Where the plaster is sound and the trouble is the surface, artex, small cracks, patches from an old fireplace, then a skim coat is the right answer and costs a fraction of the alternative. The second thing to check is damp. Plaster will not fix a wet wall. If a chimney breast is staining, or a patch by the floor keeps coming back, the cause is outside or under the floor and it needs sorting first. We would rather tell you that at the survey than skim it and watch it return. For new walls the choice is between traditional sand and cement, floated and skimmed, and plasterboard on dabs with a skim over it. Board is faster, warmer to the touch and easier to run services behind. Sand and cement is tougher where things get knocked, so it still earns its place in halls, utility rooms and anywhere a garden tool lives. Drying time is the part people underestimate. Fresh plaster is dark and needs days, not hours, before paint. A mist coat of watered down emulsion goes on first, and full coats after that. Paint it early and it peels. Ventilate the room, keep the heat gentle and steady, and give it the week.

Can you plaster one room while we live in the house?

Yes, and most of our interior work is done that way. The room is emptied or the furniture is stacked and sheeted, the floor is covered, and the doorway is screened. Plastering is wet work rather than dusty work. The dust comes from taking old plaster off, so where that is needed we seal the room and run the extraction.