How to Paint New Plaster

If you have a few rooms to paint, get a spray gun. It’ll cost about £130, save you time and get MUCH better results. I'll also tell you how to use it!

Watch the video for the main points, read below to get more...

Don't think you're in the right place? This is the first Step in a 2 part course covering painting.

This post covers just the first coats onto skim coat plaster, and takes you through each step until you're good to paint the finishing coats.

I'm confident you'll get a lot of benefit from everything on this page. However, if you're in a hurry, you can jump straight to...

INTRODUCTION

What's this about then?

This blog post covers painting on plaster for the first time. I mainly use a spray gun but I’ll cover using a roller too. The spray gun results are far superior to painting with a roller and the cleaning up was no more time consuming than using a roller. In fact, it was quicker to clean the spray gun when compared to a roller.

Do I need to PVA the plaster first?

No! Don’t do it! You may have done this before without any problems but a quick search online suggests that problems can and do occur. There is no need to PVA your plaster first, it’s completely unnecessary. The first coat of paint is what’s called a mist coat, which is a watered down coat of paint, that’s all that’s required.

Do I need to check the plaster first?

Yeah, that would be wise. Great news - I have already covered this, see here. One step ahead of you there!

Should I do this myself?

Why not? It’s so easy (providing you follow my steps), and the results look as good as any professional painter (better in my experience). The equipment is cheap, especially if you don’t want to go down the spray gun technique I describe. However, the spray gun only costs about £100 and is well worth the initial outlay, especially as it looks like I’ll be painting the whole of my house.

TOOLS FOR THE JOB

What tools will I need?

I think we all know what’s required, but I’ll cover the painting tools anyway (all links open in a new tab in Amazon by the way):

    • A painters brush (just in case you need to brush out any drip marks)
    • A clean tub (to mix the paint and water in, at least 5l capacity and ideally one that has volume marks on the inside)
    • A stick (to stir things up a bit!)

    Now, depending on whether you’re using a spray gun or roller#;

    Materials:

    • Water
    • Non-Vinyl Matt Emulsion (I used up about 6 litres over 3 coats for 30m2)
    • Sheets and masking tape (to cover everything, especially if spray painting)

CHECK THE PLASTER IS READY

OK, so I’d left my plaster for a couple of weeks before painting, but the absolute minimum time to allow plaster to dry before painting is 3 days. Sometimes though, this isn’t enough and the general advice is to give it at least a week, to be absolutely sure. I had skim coated my walls (about 2mm thick) onto plasterboard. If thicker plaster layers have been applied, you may need to leave it for longer, sometimes a month.

A way of checking the readiness of plaster before painting is by observing its colour, it should be light pink. Here’s a picture of mine just before I plastered:

Sam in kneeling in front of his plastered wall. There's no paint on it yet and it's a consistent light pink colour

You’ll also notice that, after plastering, there are damp patches and dry patches due to the plaster drying out unevenly. After a few days or so, this will even out to form a consistent brightness throughout. If you have any darker patches, even if it’s one little bit in the entire wall, wait until it has completely dried out.

PREPARATION BEFORE PAINTING

It’s worth a check for lumps and bumps, gaps and general scratch marks caused during skimming off the plaster. If you plastered it yourself and haven’t had much experience, I would recommend checking out my other blog post on this, you can find it here.

As for limiting the clean-up operation, you really need to go to town with the dust sheets, especially if you’re using the spray gun. With both methods (spray or roller) cover the entire floor with dust sheets and tape securely in place. You’ll also need to cover the windows and their frames, curtains, doors, architraves, skirting. Basically, cover anything that you don’t want paint to get onto. If using a spray gun, you’ll need to cover any light fittings in the ceiling too, plus have a mask to hand s you don’t want to be breathing in paint particles.

If you intend to use a spray gun, you’ll need to take some extra precautionary steps. Any loose sheets, even if attached at the edges, will likely flap about loads with all the air flow from the gun, so much so that they could tear. To counter this, I criss-crossed masking tape over the dust sheets. Here’s a picture of my room, you can see how I’ve covered everything and criss-crossed the masking tape:

Samd dining room completely covered with dust sheets. doors have diagonal masking tape. Sam is standing in background with his spray gun

With spray painting, you also need to protect the sockets from getting a good blast of paint. Whilst it’s not an issue with covering the inside of the socket, or a reel of wire within the socket, it may be an issue with the thread of the fixing nuts (used to attach the front plate of the socket onto the back box).

a socket back box set in a newly plastered wall. there is masking tape covering the screw holes

PAINTING THE FIRST MIST COAT ONTO NEW PLASTER

There are a few different ways of painting the first coat onto plaster, mainly using either a roller or a spray gun. I favoured the spray gun technique but I’ll cover both options for you.

The first coat of paint needs to be what’s known as a “mist coat”. It’s called a mist coat because it’s a very watered down coat of emulsion. The reason it’s watered down is so that the paint can soak into the plaster and really get a good foothold into its pores. If the first coat wasn’t watered down, the paint would sit on the surface of the plaster and there is a risk that it will flake off in time. In this post I’ll take you through the steps of mixing water with standard matt emulsion to create a perfect mist coat, it’s so easy!

I have read about people coating the plaster with a PVA/water mix prior to painting. Having spoken with professional decorators and looking extensively online, I would recommend against this. Although some people seem to have had success at this method, there are others who have had problems. Given that the solution to fixing any potential problems with using PVA is to remove the plaster and start again, to me it’s not worth the risk.

If you’re not confident in mixing your own mist coat, there are other options out there. It’s possible to purchase mist coat premixed. There’s also mist coat products out there that offer quicker drying times, although they are dearer and to be honest, I don’t think they’re necessary as the mist coat dries quick anyway.

That said, if you are in a rush, I'll cover the pre-mixed mist coast option briefly. This stuff is ready to apply directly onto plaster and does not require mixing with water, it's good to go. There's a very well reviewed product from Screwfix - No Nonsense Trade Bare Plaster Paint in Brilliant White. 10 litres will set you back £15.00 including VAT (at the time of writing). This was actually referred to me by one of my Youtube subscribers, Mr V, who was kind enough to send me the link, he swears by the stuff and by looking at the reviews, I can see why. If you don't fancy the hassle of mixing yourself, grab some of this but I should point out that I haven't used it personally, I'm just going on the reviews. Another benefit of using the pre-mixed stuff is it isn't just limited to painting directly onto plaster, it can be used as the finished white coat too.

Just one thing to bear in mind though, is the cost difference. For example, this 10 litre tub costs £15. If you bought the same brand 10 litre No Nonsense Trade Matt Emulsion in White, you'd pay £9.99. This doesn't sound like much of a saving but here's the trick, you mix that with 50% water to net 20 litres of mist coat, still at £9.99, effectively 1/3rd of the price of the pre-mixed stuff.

Ok, so back onto mixing the mist coat, you’ll need water (obviously!), any standard white emulsion paint (own brand basic stuff will do just fine) and a tub to mix it in. Oh, and a stick to stir it up.

sam pouring matt emulsion into a tub of water

The first coat wants to be really watered down. Having spoken to many painters, I found that they would mix the first coat from anything between 20% water to 50% water, so 1 part water:4 parts emulsion to 1 part water:1 part emulsion respectively. Having looked into it further, the 50% water option is best but takes more coats, and hence more time. It's best because the high water content will ensure the paint really soaks into the plaster's pores, which is the aim of the first coat. As I’m going for quality over my time, 50% water is the option I went for.

Simply put both the emulsion and water into the tub and stir it up really well. You’ll notice the water and emulsion start off separated but gradually blends to form a consistent and runny mix.

Once mixed up, you’re good to go and now is the time to decide whether to use a spray gun or roller. I’ll cover both options but first I would like to quickly discuss the merits of using both methods.

Helpful Tip

Good sandpaper isn't cheap. Just because the sand paper is choked with plaster, doesn't mean it's done with. Use a vacuum cleaner with a brush attachment to remove the plaster from the sandpaper. Then, you're good to go!

COMPARING A SPRAY GUN OR ROLLER TO APPLY THE MIST COAT

So the mist coat is a very watered down coat of emulsion and as such can be used in most spray guns. It’s actually quite common these days to find painters using spray guns, especially in new-build homes where time is of the essence.

With the mist coat, using a roller can be very messy. It’s not half as thick as un-watered paint and therefore sprays paint everywhere, unless you take it really slow that is. Using a roller, there is a risk that you don’t get the paint into all the pores and the coat can be uneven. That said, the evenness doesn’t matter too much with the mist coat because the proceeding coats will even things out nicely. Even though I used a spray gun, I have used a roller before and it would’ve taken me about an hour for each coat in my dining room.

As for cleaning down the roller, we all know how long that can take!

With the spray gun, again this is very messy work, more so than a roller to be honest. Everything in the room has to be covered, even the floor in the middle of the room. The spray particles will reach everywhere (I had to clean the lens off my camera a few times). However, you should be covering everything when using a roller anyway. The evenness of the paint was superb - very consistently spread once I’d got the technique right (see my video for the technique). It took about 15 minutes for each coat using the spray gun, far quicker than a roller.

As for cleaning down the spray gun. With the Bosch PFS 3000-2 spray gun, it took me about 5 minutes between the coats and after I’d finished.

sams holding up the spray gun,which is half assembled, to display how easy it is to take apart
The spray gun was very easy to dismantle, making it easy to clean

GENERAL MIST COAT ADVICE FOR BOTH METHODS

Even though I’ll cover both spray painting and using a roller, there’s some advice I want to give that apply to both methods.

Don’t be tempted to put a thick layer of mist coat paint on, in an attempt to speed up the whole process. The first coat will look disappointing, after doing it you’ll probably wonder what the point is because it will still appear a bit pink. At this stage, it’s worth remembering that the first coat mostly sucks into the pores of the plaster and so gets lost from view. This is good, you want it to suck into the pores!

new plaster covered in first mist coat shows up patchy, this is normal
Example of patchy results from first mist coat. Don't worry, this is normal

APPLYING THE MIST COAT USING A ROLLER

So, if you’ve not got a spray gun or don’t intend on buying one, no worries, I’ve got that covered too.

You can use the tub instead of a roller tray here, in fact I would advise it. The reason being is because the first mist coat is very runny, and will likely splash over the sides of the roller tray. If your tub has deep sides and is wide enough to get the roller in, use this instead.

Simply roll it onto the plaster, checking there are no drip marks or missed bits. You’ll need a brush to get the paint into the corners by the way.

Helpful Tip

In between coats, put your roller and tray into a plastic bag (with no holes) and tape up the openings. It’ll be good to go within 24 hours and the paint won’t have dried, saving you centuries in cleaning that roller!

APPLYING THE MIST COAT USING A SPRAY GUN

As mentioned above, I used the Bosch PFS 3000-2 spray gun, which I brought for about £130. What a bit of kit this was, oh and by the way I haven’t been paid to say this, Bosch likely don’t know I exist!

picture showing The Bosch PFS 3000-2 spray gun. consisting of a compressor box, connected to the hand held nozzle with a hose
The Bosch PFS 3000-2 spray gun

There are some mixed reviews online, especially with regards to spraying indoors. I had originally brought this gun for spraying fence panels and decided to give it a go inside, as I had the gun anyway.

I would point out that you need to be quick, very quick! If holding down the trigger constantly, it will spew out about a litre in a minute or so.

I won’t go into too much detail about using that particular model of spray gun, just the bits that are applicable to mist coating. I might do a full review at some point, we’ll see.

So, after mixing the mist coat, fill up the reservoir of the spray gun. Make one final check that everything is covered in sheets and get cracking.

Helpful Tip

Start with the guns lowest setting, just to test the water and to perfect the technique of spraying right before getting really stuck in.

I found that going in vertical lines worked best, bending my knees as I reached for the lower portion of the wall, and tip-toeing for the upper parts. I stood about half a metre back and kept the gun facing squarely at the walls. I’d also adjusted the gun so that it sprayed a horizontal fan pattern.

For the corners, I was able to adjust the gun so that it sprayed a round, circular pattern. I didn’t need to go over it again with a brush providing I was quick with the gun and didn’t get too much paint on the plaster.

With spray painting, you’ll get some paint in the open socket back boxes. Although it doesn’t cause problems with the box itself, I found that it acted as a kind of collection bucket for the paint. On one occasion, it meant I had a drip of paint running down the wall below the back box, where the collection of paint spilt out. To remedy this, I aimed my spray gun at the drip mark and, without pressing the trigger, allowed clean air to blow onto it. Effectively blasting the cr*p out of the drip until it smeared with the surrounding paint and becoming flat against the plaster. I expect most guns will still blow out clean air even when the trigger is not pressed, just like mine.

Once you build up your confidence, have a go at turning up the speed of gun. I ended up turning mine at full pelt and coated the room in no more than 10 minutes, with no detriment to the finish quality.

PAINTING THE SECOND AND THIRD MIST COATS

The first coat will dry out really quickly - it was about 20-30 minutes after applying my first coat that I found it had dried. You want to give it longer though, just to give it a fighting chance of drying deep down within the pores of the plaster, which isn’t noticeable on the surface. Give it at least an hour and make yourself a brew.

picture of plaster skim coat being sprayed with white emulsion and water mist coat with pray jetting out the nozzle

For the second coat using the spray gun method, this will take longer to dry because it’s not being applied directly to plaster and hence won’t have the moisture sucked out of it. Again, it may feel dry after 30-40 minutes, but allow it 1½ to 2 hours to fully dry.

Helpful Tip

For the second coat using a roller, this can be neat emulsion, there’s no need to water this one down. Allow it to dry overnight before painting over.

The 2nd and 3rd coats using the spray gun are done much the same as the first coat, with one key difference – the ratio of water to emulsion paint. There’s no set ratio as far as I can tell, everyone is using slightly different quantities but here’s what works for me.

Spray painting ratios for mist coat (it’s what worked for me):

1st Coat – 50% water & 50% emulsion (I used 3.5 litres for 30m2)

2nd Coat – Again 50% water & 50% emulsion

3rd coat – 25% water & 75% emulsion

Paint rolling ratios for the mist coat, taken from a multitude of online and professional advice:

1st Coat – between 50% and 30% water (50% and 70% emulsion respectively)

2nd Coat – Neat matt emulsion.

The reason I have included a neat emulsion as the 2nd coat for the roller option, is because that’s what’s required to bring the finish comparable with 3 watered down coats using the spray gun.

After these coats, you can continue to paint the walls using either an un-mixed emulsion or base coat until it’s a consistent white finish. After which, you can apply the final coats of coloured paint.

I should point out that, with the final mist coat (75% emulsion), this was the maximum ratio of emulsion for this particular spray gun. It does suggest 90% emulsion is OK, but I found that 75% emulsion was probably the most before getting issues, such as clogging of the nozzle.

If you’re using a spray gun and the ratio differs, make sure you stick to the recommendations or play around with finding the right ratio. One sign that the coat was too thick was that the needle (within the gun) wouldn’t return back to its resting position when I let go of the trigger. This meant that the flow of air and paint didn’t completely stop and the gun ended up constantly spraying, albeit much less than when I had the trigger pressed in.

AFTER APPLYING THE MIST COATS

There are a few things you should do at this stage that will save you hassle later on.

Now that the mist coat is on, it’s a good idea to check for any lumps and bumps that you may have missed off prior to applying the mist coat. Note: this applies after the first coat using a roller, before painting on the neat, un-watered coat. The main reason is because it’s actually easier to see the bumps, especially any depressions, after the mist coat is applied.

If you do find any, fill them in using any standard filler. Once dried, sand them off and be sure to apply a mist coat on its surface prior to carrying on with the finishing coats of paint.

And finally, get those tools cleaned, make yourself a cuppa and send me a photo.

This is Step 1 of my course on painting walls, the next How-to will talk about painting on top of the mist coat and will cover rolling and brushing techniques, it’s going to be pretty comprehensive. The previous post was all about preparing plaster ready for painting, and goes into detail on ensuring you have the best chance for a good finish.

So, if you're eager to put those finishing coats of paint onto the mist coat, don't worry, I've got it covered in the next How-to.

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