How to repair lots of blown Plaster and cracks on walls

by Rachel

Can you please advise me what to do to prepare walls which are blown in a lot of different places. We are renovating our whole house and every wall has quite a lot of blown plaster on it. I was then thinking of putting a finishing coat on top of the prepared walls.

I am grateful for as much advice as you're able to share please.

We are needing to to the work ourselves to keep the costs down.

Thank you and kind regards,



Hi Rachel

If it is just the skim (top coat approx 2mm thick) then remove loose plaster and patch area with new plaster. When skimming - never lose sight of your edges - keep existing plaster clean. Patching is not the easiest aspect of plastering - as it can be hard to obtain a seamless join. If you have a large wall with just a small area to patch - then have a go - but if you have a large or multiple patches then it can be easier to apply PVA to the whole wall and skim the whole wall.
If the backing coat has also blown then, as you say, you will need to repair this backing coat prior to skimming the wall - it is always a 2 stage process of backing coat and skim coat. Do not be tempted to do it all in one go. Wet the edges of existing plaster, apply the backing coat, rule flat. If skimming the whole wall - then leave flat, as it is firming up - carefully push the plaster into the edge, to ensure it has properly bonded. If patching then as you push the plaster in to the edge - take a bit more care to ensure you have a small amount of depth differential for your skim coat to be applied. Even 0.5 mm is okay but at the very least ensure no backing coat is sticking proud of existing plaster.

Patching is time consuming and can be trickier than people first realise - so take your time.

Good luck

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