Definition
A skim coat is a thin layer of joint compound spread over an entire wall or ceiling to make the surface smooth and uniform.
Skim Coat, Explained
Skim coating means troweling a very thin coat of joint compound over the whole surface, then sanding it smooth. Sometimes it takes two coats.
It’s used to fix walls that are rough, patched, or damaged, for example after removing wallpaper, on old plaster with cracks and repairs, or on drywall where the paper was torn. It’s also the step that turns a Level 4 drywall finish into Level 5.
In older Chicago homes with plaster walls, skim coating is often the alternative to tearing plaster out: the walls stay, and the surface is made new.
Why It Matters for Your Project
Paint shows every flaw beneath it. Skim coating is often cheaper and less messy than replacing walls, and it gives a much better result than painting over damaged surfaces.
What to Watch For
- Loose or crumbling plaster needs repair before skimming; a skim coat won’t hold it.
- Skim-coated walls need primer before paint.
- Expect dust from sanding; ask how it will be contained.
- Ask whether one or two coats are included in the price.