Can You Plaster Over Plaster?
It is possible to plaster over plaster, however, it’s not always recommended. The condition of the existing plaster will determine whether it is strong enough to hold a new layer of plaster. If the existing plaster is weak or damp it may blow, so in this case you should remove the old plaster and start from scratch. In some cases, you may be able to patch the weak sections with a fibreglass mesh, but this would only be suitable for a very small area.
When replastering a wall, it’s essential to start with a clean surface. You can apply a bonding agent to the existing plaster which helps to create an even surface and improve adhesion between the old and new plaster. You can also use waterproofing agents to treat any damp areas.
Consider The Existing Plaster's Condition
When deciding whether to remove the existing plaster or not, the key question is what condition is the existing plaster in? If it is cracked, covered in residual coatings, or has lumps and bumps, you should remove it. Trying to plaster over these problems could cause structural issues with the new layer of plaster. If the plaster is in good condition, then you can often plaster over it.
Whilst it may be possible to skip the removal stage and directly put new plaster over the top, it won’t result in a smooth finish. It is much harder to achieve a good even coverage when plastering over existing plaster, so you may need to sand the final surface once dry.
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Get a QuoteCan You Plaster Over Artex?
The majority of Artex surfaces can be plastered over, however, there are some exceptions. If your Artex contains asbestos, it must be removed by a professional. Artex which contains cellulose paint or oil-based paint should be completely removed before any new plaster is applied.
If your Artex is fine to stay, you need to make sure that it is firmly bonded to the wall, and also free from dirt or any loose bits or pieces. You can increase the bonding of the Artex by cleaning it and then brushing it with PVA glue. Then you can apply a water-resistant sealer and apply a scratch layer of plaster before the final coats.
Why does plaster blow and how to stop it?
Plaster can blow for a number of reasons. This usually occurs when the plaster isn’t properly mixed, causing it to fail to adhere to the wall. Other factors such as old paint, moisture in the wall, or high humidity can all contribute to plaster blowing. To avoid this problem, it is best to thoroughly prepare the surface by ensuring it is perfectly smooth and free from dust, dirt, and other materials. Using a water-resistant sealer or an undercoat will also help to prevent plaster blowing.
Is It Possible to Plaster Onto Timber?
Plastering onto timber is possible but with extra caution, as timber expands and contracts in different temperatures. Therefore, it is essential that you use an adequately sized batten to fix the plasterboard to the timber, as this will ensure secure and accurate fixing. Heat-reflective foil or breathable membranes can also be used to reduce any shrinkage or expansion when temperatures change.
It is important to note that all timberwork should be properly sealed and primed prior to plastering. Again, using a water-resistant sealer or an undercoat will help to protect the timber and can also reduce the risk of blow-through. Once fixed correctly, the plastering process should be similar to that of plastering onto other surfaces.
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