how to replaster a wall

February 26, 2026

To replaster a wall, you first strip back loose or damaged plaster, prepare the surface so new plaster can stick properly, then apply one or two new coats and smooth them ready for paint. Taking time with preparation and drying is what separates a smooth, long‑lasting finish from one that cracks or flakes quickly.

Tools and materials

You will typically need:

Plaster (finishing/skim plaster suitable for interiors)
PVA glue or other bonding agent
Buckets and mixing paddle or drill mixer
Trowel, hawk, plasterer’s float, corner/angle beads if edges are exposed
Scraper, filling knife, sanding blocks/paper (medium and fine)
Dust sheets, masking tape, safety glasses, dust mask, gloves

Step 1: Assess and prep the wall

Good plastering starts with a sound, clean surface and no hidden problems.

Check for damp patches, deep structural cracks, or loose masonry; fix those (or get a pro) before replastering, otherwise the new plaster will fail.

Scrape off all loose or flaking plaster, paint, and wallpaper, and vacuum or brush away dust so the wall is firm and clean.

Step 2: Key and bond the surface

A “keyed” and primed surface helps the new plaster grip and stop it drying too fast.

Score smooth areas lightly or rough up glossy paint with sandpaper to give texture, especially if you are going over old paint.

Mix PVA with water (often around 1:4–1:5, always follow the bottle instructions) and brush it over the wall; let it go tacky rather than fully dry before you plaster.

Step 3: Mix the plaster

Only mix what you can comfortably apply in its working time (often 30–40 minutes).

Pour clean water into a bucket first, then gradually add plaster powder, mixing with a paddle until smooth, lump‑free, and thick enough to hang on a trowel without running.

Let the mix stand briefly, then remix to a creamy consistency, adjusting with tiny amounts of water or powder if needed.

Step 4: Apply the first coat

The first coat levels the wall and provides a base (often called a scratch or base coat).

Load plaster onto your hawk, pick it up with the trowel, and apply in firm, sweeping strokes from bottom up, keeping a slight angle on the trowel.

Aim for a roughly even layer around 5–7 mm thick, filling hollows more than high spots, and run beads on external corners if needed for straight edges.

Step 5: Flatten and scratch (if two‑coat)

As the first coat firms, you tame ridges and help the next coat bond.

Once it starts to stiffen but is not fully hard, go over it with the trowel or float to flatten ridges and fill obvious dips with spare plaster.

If using a traditional two‑coat method, lightly scratch lines into the surface with a comb or notched trowel to create a “key” for the next coat.

Step 6: Apply the finish coat

The finish (skim) coat gives you that smooth, paint‑ready surface.

Mix a fresh, slightly looser batch of plaster and apply a thinner coat, about 2–3 mm, working over small areas so you can keep control.

Keep the trowel clean and use long strokes, overlapping slightly so you don’t leave lines, and keep checking the wall from different angles for humps.

Step 7: Trowel, polish, and sand

Most of the smoothness comes from timing your passes as the plaster firms.

As the finish coat starts to set, mist the surface lightly with clean water and trowel again to close pores and remove fine lines.

After it fully dries, sand lightly with fine paper to knock back tiny imperfections before painting; fill any remaining low spots and spot‑sand again.

Drying, painting, and safety

Patience and basic safety make the job cleaner and safer.

Let plaster dry completely (often several days until it turns pale and even) before mist‑coating with diluted emulsion and then full coats of paint.

Wear a mask and goggles when sanding and mixing, cover floors with dust sheets, and avoid overreaching from ladders when working higher areas.

Information gathered from public forums or data available on the internet and portrayed here.