Can I Paint Straight Onto New Plaster?


Painting new plaster UK – It can seem like a daunting task especially if you’re painting plaster walls first time. If you are not sure where to start then ensure you read the full article as we answer the question, can I paint straight onto new plaster?

Painting a newly plastered wall takes a lot more preparation than painting a normal wall. It’s important that you don’t start painting the wall directly with any kind of paint you have but instead take the time to access the plaster and choose the correct paint for new plaster. You need to take time to properly seal the plaster so you can protect the wall and get the final smooth finish that you want.

To complete the perfect base on plaster that’s ready for painting then you need to apply a mist coat or use a specialised bare plaster paint.

So, to briefly answer the question of can I paint straight onto new plaster? Well, without preparing what we call a mist coat – an undercoat to seal the plaster – or using a bare plaster paint then the answer is no. You first need to seal the newly plastered wall for the best results before applying normal paint.

can I paint straight onto plaster?

What Is A Mist Coat For Plaster?

A mist coat is an undercoat that seals the plaster and is made up of emulsion that has been diluted with water. It’s perfect for painting and preparing new plaster that has not been treated previously. The need for a mist coat instead of non-diluted emulsion paint is that standard emulsion paint will be too thick to paint onto fresh plaster effectively. It would take a lot longer to dry and will not correctly seal the plaster. You need the water in the mist coat to seep and sink into the plaster to create a protective seal to allow the paint to bond with the mist coat when you move onto apply your normal emulsion paint.

If the standard emulsion is painted onto untreated new plaster you risk the final finish cracking and peeling and without properly sealing the plaster with a mist coat you are going to have to start the process again as the paint will not last and you may need to do some repair work.

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What Is The Ratio For a Mist Coat?

You may be wondering what’s the best mist coat ration for new plaster that you should be used when mixing your emulsion matt paint. If you’ve done a quick search before to find the answer then you’ll be quite confused with all the suggestions. Truth is there’s no best ratio to use. It depends on the product and the wall.

You do however need a thin consistency as the name suggests a mist coat should not be thick emulsion but diluted. There are claims that as low as 50/50 ratio is the best or 4 parts paint and 1 part water makes the best mist coat.

Both can work, not one is the correct answer. If you asked what the best mist coat ratio then it would be a 70% emulsion to 30% water. It’s where we often see the best results and has become our most used mist coat ratio. Once the paint is mixed and you think that it’s too thick still then you can add more water to the paint.

Not everyone will agree although and that’s okay. We all have different working methods but to be safe use a mist coat of 70% paint to 30% water. You can always adjust if needed.

What Type of Paint Can You Use On Newly Plastered Walls?

For a mist coat, make sure that you use any standard general white matt emulsion, as long as it’s a light colour you should be fine. Magnolia would be a good substitute if you have some lying about. Matt emulsion that’s dark in shade should not be used, not only does it make the paint harder to see when on the wall but also makes covering it a difficult task.

A general white emulsion should be used but make sure that you don’t mix and apply a vinyl matt mist coat or a silk mist coat to newly plastered walls. Why shouldn’t you use vinyl or silk emulsion for plaster? These types of paint create a film on the top of the paint and struggle to stick to the plaster. This can cause the mist coat to peel and crack easily.

Just use a standard matt paint mixed with 30% water to 70% paint to avoid any issues.

What Is Bare Plaster Paint?

Bare plaster paint is a specialised paint that’s developed for fresh or new plastered walls to provide a base coat before applying paint. Bare plaster paint is more available and affordable than it used to be a few years ago but expect it still to be a much more expensive option for painting new plaster.

You will expect to pay around twice as much as what it will cost you to apply a bare plaster paint when compared to mixing your own mist coat. Available from most large paint brands such as Dulux, Crown and Johnstone’s bare plaster paint is easily attainable and they do have some benefits especially for newly plastered walls.

Developed to allow the plaster to breathe they can be applied to newly plastered walls that aren’t fully dried. While I say that, I don’t mean you can apply bare plaster paint to walls that have been plastered the day before. You do need to let the plaster dry but bare plaster paint continues to allow the plaster to dry out whereas a mist coat seals the plaster and will rebound any moisture that’s still within the plaster.

Summary – Can I Paint Straight Onto New Plaster?

So, there you have it. To summarise everything previously mentioned and answer the question, can I paint straight onto newly plastered walls? No, you need to either use a mist coat which is diluted general-purpose white matt paint. Or, a bare plaster paint that’s specifically developed for new plaster first.

Once that mist coat or bare plaster paint is applied allow it to fully dry for at least 24 hours before you go on to apply your final coats. Usually, 1 mist coat is sufficient but 2 will not cause issues and a final coat of your finishing paint should be enough.

Hope this answers your question, can I paint straight onto new plaster? and best of luck when painting plaster walls the first time.

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