Follow with two full, undiluted coats to finish. Start by opening doors and windows, and don't start painting until the plaster is bone dry. This could mean waiting a few days or even weeks for a room to dry. It is worth the wait though to do it right. Follow these steps for perfect results every time.
Plaster will suck up any moisture like a sponge, so the longer you leave it to dry, the easier it will be to achieve an even result. The time it takes for plaster to dry out will depend on the room's temperature, ventilation and the plaster's thickness.
As a general rule, wait four weeks per 5mm of plaster depth. Ensure that there are no dark patches on the freshly-plastered surface before you being to paint — a uniform, light, color is a good indicator as to whether your plaster has dried thoroughly. Newly built or altered rooms also take a while to settle, so waiting will mean you can fill any cracks that form as a result, before you paint.
Fresh plaster is extremely porous, and any moisture will be quickly absorbed into the wall. This is why you need to water down your first paint layer known as a mist coat. To make a mist coat, combine a cheaper emulsion paint in a similar color to your top coat with water. The ratios for this will vary according to the paint you are using, so check what it says on your paint tin — but around three parts paint to one part water should suffice.
Stir the solution until you have an even consistency with no water sitting on top of the paint. Fresh plaster needs to be able to breath underneath the paint to allow any moisture to escape, so make sure to use a non-vinyl water-based paint. Top tip: If you have lots of rooms to paint, a big batch of white trade emulsion will see you through several rooms worth of mist coat.
Applying the first coat of mist paint can be a messy job as the paint will be thin and runny, so make sure you have put down dust sheets and covered any furniture. Pour the mist coat into a paint tray then roll an even amount on to a foam roller. Despite the above, there are things that you can do to aid the natural drying process e. If possible, open all windows and doors to help create as much ventilation and through-draft as you can as this will help with the natural drying of your new plaster.
If you are in a hurry to paint your wall because Grandma is coming to stay, there are paints on the market called Microporous Paints. These paints allow the surface of the plaster or indeed artex to carry on breathing and evaporating while they are drying out.
They can be found in a lot of DIY stores and decorators merchants. Microporous paints are generally a lot thinner than ordinary water or solvent based paints and in a lot of cases, once the wall is dry, it is recommended that you over-paint them with emulsion because of this, but only when the plaster is totally dry.
Although this method is a solution if you are in a real rush, we would always recommend waiting the required drying time before painting new plaster.
In the majority of cases, you will never get a finish you are totally happy with when rushing, regardless of whether you use specialist products or not. The answer to this really depends on who has done the plastering.
If you have hired a time-served professional plasterer to do the work for you, you can be pretty sure that the results of his labours are going to be of a high standard.
Despite the quality of the work of a professional, corners of trowels can catch, dust and debris in the air can settle of freshly plastered surfaces and other workers onsite can accidentally mark surfaces with tools, bits of timber, hard hats etc….
If you have had a go at the plastering yourself then you may have left a few trowel strokes or slight imperfections that need a little attention. With the above in mind, if you do notice any marks, debris, scratches, lumps etc….
Use paper somewhere between and grit to gently rub any marks out. Gently run the paper over the surface. Regularly check progress by using your hand and finger tips, and running them over the surface.
Once the mark or damage has been rubbed out you should feel no difference between the affected area and plastered surface around it. If you find any dips in the surface, these can be filled after you have applied your mist coat as you will be able to see the extent of the damage a little better. Using a suitable filler, apply it over the damaged area using a filling knife, wait for it to dry and then sand it back to match the surface around it. It can then be painted. When it comes to actually painting new plaster, the first coat that you apply will be a mist coat.
Well, a mist coat is essentially a watered down matt emulsion more about this below. When we say a matt emulsion, we mean the general purpose water-based not oil or vinyl based matt emulsion paint that is available from pretty much all DIY stores. A water based and diluted matt emission will bond and adhere to the plaster, giving you a good base to work and build on.
This paint-type will also allow the plaster beneath it to breathe, avoiding trapping any moisture that could cause damp patches and other issues down the line. Do not use vinyl or silk paints! As PVA is essentially a waterproof sealer, it will prevent the paint from soaking into the plaster and through this creating the necessary bond that will ensure it stays stuck to the plaster itself.
Finally, use a light coloured matt, preferably white. A light neutral colour will provide a good base for your finishing topcoat paint, which can be any colour of your choosing. New and freshly laid plaster and also freshly laid artex is very porous indeed.
If you apply any kind of ordinary paint directly onto either of these surfaces, any moisture will immediately be sucked out of that paint before it has a chance to dry naturally. In simple terms this leaves the paint going dry on the surface only and because the moisture has been sucked out so quickly, it has no "roots" or "key" to bond correctly. Sealing means applying a coating which is diluted enough to enter the pores of the material with the emulsion or liquid with which its mixed.
When applying a mist coat paint to a surface such as this, sometimes you can even hear the bare plaster or artex sucking the moisture from the mix. Use a suitable measuring jug to measure out the correct quantity of matt emulsion paint and then pour it into your paint kettle. Then measure out the required quantity of fresh, clean water and pour that in too and mix it thoroughly using a clean stick or even drill with a mixing paddle.
Once mixed, apply using a brush to a small area of bare plaster. While the plaster is drying, put down dust sheets and use your tape to protect any fixtures and fittings — applying a mist coat can be very messy!
A mist coat is made of watered-down emulsion paint and acts as a primer. The extra moisture gives the wall something to absorb so your topcoat should stick. Alternatively, you can use a water-based primer which saves you the mess of making a mist coat.
All our primers are water-based and will help you achieve an even and colourful finish. To make a mist coat, mix three parts emulsion with one part water. However, you choose to apply the coat, work in smooth upward motions until you cover the entire wall.
The mist coat is very runny so whenever you spot drips or streaks, paint over them quickly to prevent them from drying and ruining your perfect finish. As soon as your mist coat has dried you can decorate normally.
Apply the topcoat in a V motion for even coverage. For the best results, you may need to apply more than one coat. To find out how to paint your walls like a professional, have a look at our guide.
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