Painting new plaster is a key step in transforming your home decor. Fortunately, producing a nice smooth finish in the colour you love is a relatively simple and cost-effective way of giving your home a stunning new look.
Before you get started though, there are three common questions that DIY enthusiasts often ask when it comes to painting new plaster:
In this post, I'lll tackle all these questions and more.
Please note that this article only deals with painting INTERNAL walls and ceilings.
Picking the right paint depends on the room you're painting, the plaster type and your budget.
The humidity in kitchens and bathrooms cause water-based paints (emulsions) to soak up the water vapour, which can make them unstable and likely to peel or harbour mould spores. Therefore, it's best to use solvent-based paints for kitchens and bathrooms. Some companies even make special kitchen and bathroom paints which come in a vast range of colours.
For the other rooms in your home, go with good quality emulsion paints. A good quality paint will need less coats, last longer and produce a much better finish when compared with cheaper paints. Use this link to find the best options for your home.
Freshly plastered walls must be left to dry out completely before you start painting.
Drying time depends on several factors such as; time of year, central heating, plaster type and the number of plastered layers.
However, you can expect the plaster to be completely dry after about three weeks, but this assumes you have central heating. If you don't have central heating, it could take up to 6 weeks.
A freshly plastered wall is much closer to the colour in Fig.1 than Fig. 2 (see images below). Once the wall is completely dry, the wall should match the colour in Fig. 2. and be uniform in its colour.
You shouldn’t paint plaster before it's completely dry because paint forms an airtight skin on top of the plaster.
This airtight skin results in moisture being trapped underneath the paint instead of evaporating off the plaster. Trapped moisture will either move deeper and develop mould in the wall, or will mix with wall salts and become Efflorescence.
In either scenario, you’ll have an expensive problem to fix. As always, prevention is better than cure!
Make sure freshly plastered rooms are well ventilated by opening doors and windows. This will allow natural air ventilation to flow through the room, gently drying your plaster.
Don’t be tempted to turn the heating up full whack, as rapidly drying plaster can cause cracking.
All the prep work listed below should have already been done for the plastering process. However, just in case they haven't, here are the essential steps:
For much more info on how to prepare a room for painting, please check out my guide to Painting A Room With No Mess – 27 Top Tips.
Look closely at the surface and you will most likely see unwanted little blobs and drops of plaster. They are not so obvious at first, but they stand out later when you’ve finished painting. Use a scraper to remove all the bits you find.
Fresh plaster is extremely porous, so if you use undiluted paint, the paint’s moisture will be sucked up by the plaster. The result is dry paint that won’t bond with the plaster.
Therefore, you must seal the plaster before applying the finish paint. For water-based paints, seal the plaster with a mist coat. A mist coat is a diluted coat that the plaster will suck up like a sponge and fill its pores.
For solvent-based paint (used for kitchens and bathrooms) use PVA as your sealer.
Important Note: Make sure that you do NOT use a vinyl emulsion for your mist coat. Vinyl emulsion forms a skin on the surface of your plaster that will be prone to peeling.
As mentioned above, solvent-based paints should be sealed with a PVA adhesive and NOT a mist coat. PVA should also be mixed with water and by the same ratio as below.
1. Mix Emulsion With Water
Note: Depending on your emulsion, you may have to alter the above ratio to achieve the right mix. If you need more info, check out this mist coat guide.
2. Apply Mist Coat On Walls
Once the mist coat has dried, imperfections should be filled and sanded down.
Once the filler touch-ups have dried, your wall/ceiling is ready for its finish coats.
Apply two or three finish coats by following the same steps used for the mist coat
For more information on painting, please check out this article, under the heading ‘Painting Technique’. You'll find some great tips on how best to use rollers and brushes, so I highly recommend you check this out before you start painting.
I hope you found this post useful and now feel empowered to paint your freshly laid plaster. If you want to see how the pros do it, check out this video:
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