What good plastering should look like
Plaster is the base for every finish that follows. If it is not flat and sound, no amount of paint will hide it. Here is what to look for.
Plastering is one of those jobs where you only notice it when it is done badly. Get it right and it disappears under the paint. Get it wrong and you see every ripple and trowel mark once the light hits it.
Flat, and flat in the light
A good skim is smooth to the hand and, more importantly, flat when you look along it in daylight. That side-on light is the real test. Hollows, high spots and trowel lines all jump out under it, and they will jump out even more once there is paint on the wall catching the same light.
Sound underneath
Old plaster on London walls often bulges or blows, meaning it has come away from the wall behind. Painting over that just delays the crack. Where the old plaster is past saving we take it back and replaster. Where it is only tired, a skim over the top brings it back to smooth.
Give it time to dry
Fresh plaster needs to dry out fully before it is painted, and how long depends on the room and the weather. Paint it too soon and you seal the moisture in, which leads to patchy colour and worse down the line. It is worth the wait. A mist coat first, then your proper coats, and it will look the part for years.
