Repair a Plaster Wall With Filler When You Can't Plaster

The Problem

Real plastering is a skill with a years-long learning curve — the mix, the timing, the trowel work. But a blown patch of old plaster doesn't care about your skill level, and calling a plasterer for one damaged section is expensive overkill. There's a route to a flat, paintable wall that doesn't require knowing how to plaster at all.

The Technique

1. Remove all the failed plaster. Anything loose or blown comes off the wall — a patch over bad plaster fails with it.
2. Prime with PVA. Coat the exposed areas with any PVA-based product. It seals the dusty, thirsty substrate so the filler bonds instead of drying out on contact.
3. Mix an easy-sand filler to spec. Ready-mix bagged filler, mixed to the ratio on the bag, stirred until every lump is out. Right consistency: it stays on the trowel — think stiff icing.
4. Overfill slightly. Lay it on a touch proud of the wall and go past the edges of the damage. Nobody wants to come back and fill twice; sanding down excess is easy, filling a low spot again is not.
5. Don't overwork it. This is the mistake that ruins the job: chasing every little trowel line, working the surface over and over. Keep troweling and you'll drag through the patch and pick bits off the wall. Get it on, get it roughly flat, and walk away.
6. Sand flat the next day. Once fully dry, sand it flush and it's ready to decorate.

Wash your tools when you're done so they don't rust.