A mist coat is a thin, watered-down first coat of emulsion paint used on newly plastered walls to seal the porous surface and help the next coats stick properly.

Quick Scoop

It is usually made by diluting emulsion paint with water, then applying it to bare plaster before the topcoats. The coat does not need full coverage at this stage; a slightly patchy finish is normal because its main job is to soak in and bind the surface.

Why It Matters

Fresh plaster can absorb paint very quickly, which can lead to uneven drying or poor adhesion if you skip the mist coat. Using it helps create a better base for the final paint finish and reduces the chance of peeling or flaking later.

How It’s Used

A common approach is to mix the paint thinly, then apply it with a brush around the edges and a roller over larger areas. After it dries fully, you normally apply the final coats on top.

TL;DR

A mist coat is just the first thinned coat on new plaster, used to seal it before normal painting begins.