How To Paint New Plaster Walls

If your considering painting new plaster walls, STOP, take 5 mins and read my article on how to paint newly plastered walls. One of the biggest mistakes DIY enthusiasts make is not sealing new plaster before applying the top coats of paint. This is disastrous and difficult to rectify once the mistake has been made.

Can you paint directly on new plaster, the answer NO

Save yourself valuable time and avoid costly mistakes. Below I explain why you need to seal new plaster, how to mist coat and what products to use.

How Soon Can I Paint New Plaster?

All newly plastered walls require a base coat called a (mist coat), this serves as a primer coat of paint sealing the plaster. Before we can start to prime our walls, we first must ensure that the plaster is dry. If moisture is present the primer coat will not adhere to the new plaster.

Fresh plaster is dark grey / brown in colour, as it dries it turns a light creamy pink. Your new plaster is dry once the entire area is the same colour, (light creamy pink). If there are still dark grey patches evident, wait until they dry before mist coating.

The drying times of new plaster vary depending on temperature and humidity. As a guide new plaster walls can take an average of 2 – 6 days to dry. If in doubt, wait another day or two, I cannot stress this enough. New plaster must be dry before starting to paint.

Painting New Plaster Walls

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Painting New Plaster Walls

The method of painting fresh plaster is relatively simply, just follow the steps below to avoid any issues in the future. Below I explain how to dilute contract emulsion and what painting tools will help get the job done faster.

1) Ensure the plaster is dry before mist coating the walls or ceiling.

2) Use a basic Contract Emulsion Paint, you don’t need special paint for priming new plaster. Do not use vinyl matt emulsion.

Contract matt emulsion is readily available and cheap, once watered down to the correct ratio is perfect for painting new plaster walls.

To successfully mist coat new plaster, contract emulsion must be watered down. The reason you water down the paint is allow the new plaster to absorb the paint sealing the plaster for your top coats of paint.

3) Dilute the Contract Emulsion following the mist coat new plaster ratios below.

4) Apply a mist coat to your new plaster and allow to dry for 24 hours.

Mist Coat Ratios

70% emulsion 30% water
60% emulsion 40% water
50% emulsion 50% water

Why are there several dilution ratios? All three ratios above will work for mist coating new plaster. If for example your painting a room with no furniture, no flooring, a ratio of 50% emulsion and 50% water would suit the environment.

Painting with diluted paint can be messy, so if you can base coat the new plaster without having to add too much water will reduce paint splatter.

I personally use the middle ratio 60% emulsion and 40% water with great success. The brand of paint can also reflect the mist coat ratio as some paints are thicker than others. As a guide, contract emulsion once diluted should run easily of both your roller sleeve and brush.

For smaller plaster repairs or areas where there is significant amount of furniture present. A mist coat ratio of 70% emulsion and 30% water would be adequate.

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How To Dilute Paint With Water

You will need 1) Contract emulsion paint, 2) Large clean bucket, 3) Mixing paddle 4) Electric drill. Pour the contract emulsion into the bucket leaving enough room for the water, then add the correct percentage of water.

Attach the mixing paddle to your electric drill and gradually mix the paint and water together. Start slowly or the paint will splash, mix thoroughly for a min of 2 – 3 mins or until the paint is the same consistency.

If you don’t have a mixing paddle or electric drill, you can use a Paint Mixing Stick or something similar. The end result will be the same, it will just take longer to mix the paint and water together.

Tools For Painting Bare Plaster

Below is a list of painting tools that will make the job of painting new plaster walls a breeze.

One of the most important items from the list above is dust sheets. As I mentioned earlier emulsion paint once diluted is messy, you will need to cover everything you do not wish to get paint on. I use a combination of Heavy Duty Twill Dust Sheets for flooring and furniture. I also use Prodec Super Cling Dust Sheet for worktops, cupboards, units, large appliances.

When painting, I recommend wearing a pair of Safety Glasses to avoid paint splatter from getting into your eyes.

How Many Mist Coats On New Plaster

The number of mist coats depends on the condition of the new plaster. Even though your new walls have been freshly plastered, they may still need a light sand and a fill in places. If this is the case then a second mist coat would be beneficial.

Another factor is the colour of the plaster, if you can still see the original colour (light creamy pink) showing through. Then another mist coat would be advisable.

In most cases I apply the first mist coat to seal the plaster. I then give the plaster a light sand with 120 Grade Sandpaper, fill any areas that need attention and then a final mist coat.

Before attempting to sand or fill newly mist coated plaster, WAIT for 24 hours, giving the paint a chance to cure and harden.

When applying your top coats of paint, wait a further 24 hours to allow your second mist coat to cure. By following the method above will ensure that you do not have any recurring problems with paint peeling in future years.

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Disclaimer

This blog is a personal blog written and edited by me (Andrew Firth). For questions about this blog, please contact andrew@clearcutpainting.co.uk

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