How to paint on new plaster

Painting on newly-plastered walls will save you the hassle of putting up lining paper, but follow our simple step-by-step guide to ensure you get a professional finish

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Painting a room is pretty much the easiest DIY out there, anyone armed with a paint brush and some emulsion can do an adequate job. But painting a room that has been newly-plastered is a whole different ball game. However, don’t be put off, it’s still a job you can tackle yourself, it just needs more patience and preparation. 

To help you get to grips with the unusual properties of fresh plaster, we’ve put together a simple step-by-step guide to ensure you get a professional finish. 

What you will need

1. Make sure the plaster is dry 

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, colour is a good indicator as to whether your plaster has dried thoroughly. 

2. Make a mist coat 

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 colour 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.

3. Prime with a 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. Fix masking tape along the skirting boards and any trim to protect them, and cover light switches or sockets and windows. Pour the mist coat into a paint tray then roll an even amount on to a foam roller. Roll it over the plaster in smooth, upward motions until you have covered the whole surface. Use a smaller paint brush to get into any corners or areas that cannot be reached with the roller. 

Top tip: When applying your mist layer, keep an eye out for any drips, rolling over them before they dry.

4. Allow the mist coat to dry 

A mist coat will take around 24 hours to dry, but this will depend on the conditions in the room. Once dry, you can start applying top coats. 

5. Apply the top coats

If you are right handed, start in the top left hand corner of a wall and work to the right. If you are left handed, work in the opposite direction. This will stop you getting any paint on your beloved decorating dungarees. Cut in around the corners of the wall using a brush and fill the rest of the wall using a roller. Allow the first coat to dry thoroughly (overnight if you are unsure) before adding a second coat. 

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