Can you paint straight onto plasterboard?
So you’ve got a bare plasterboard wall and want to get it painted right away. But something nagging away in the back of your brain, is there something you should do first? Well, let’s have a look and find out if you can paint straight onto plasterboard or if it requires some prep work first.
Can you paint straight onto plasterboard?
Yes, you can paint directly onto plasterboard. You should, however, paint a mist coat on first. A mist coat is simply a watered-down first coat of emulsion paint. This helps to seal the plasterboard and stops your next coat of paint from soaking in as much.
Mist Coat
The first step you want to take when painting straight onto plasterboard is laying down a mist coat first. A mist coat is simply a coat of emulsion watered down. For me, the best ratio was 2:1, 2 parts paint to 1 part water.
This was a good medium of allowing the paint to go much further and thus save money while not being too thin to paint well. To do this simply pour a reasonable amount for the size of your wall into a separate bucket and then add some water. If you want to see the testing that went into perfecting this ratio then I have a whole article dedicated to mist coat ratios.
This mist coat essentially acts as a sealer. It will soak into the plasterboard but this is good, this is what you want it to do. This initial mist coat will give you a really good base to build on.
Paint as normal
Once your first mist coat is down you can then paint as normal with a regular emulsion. I recommend using a roller for painting large flat surfaces.
Joint filler
You will need to ensure you are painting onto a really nice smooth surface as the level of surface finish will show in the final result. If you are painting straight onto plasterboard then you obviously don’t have a skim coat.
This is not the end of the world and you can achieve a really good level of finish without a skim coat. But you will need to ensure any imperfections are filled and that your joints are filled well with a good joint filler.
The plasterboard joint will be one of the hardest areas to get smooth. Don’t be afraid to sand down and then re-apply filler if you are finding it tough to get a really smooth finish on the plasterboard joints.
You can use paper jointing tape in coordination with joint filler to help fill the gaps between plasterboard sheets. Then sand down the joint filler to achieve a nice smooth joint.
Tapered Edge Plasterboard
As its name suggests, tapered edge plasterboard has a small taper on the edge of each board. There is one reason tapered edge plasterboard exists, and that is dry lining. Dry lining is where your walls are never plastered and instead, the plasterboard is painted to leave your finished walls.
Tapered edge plasterboard sheets are used in this situation because you can get a much cleaner finish.
With the gap between the two sheets being tapered it actually sits below the rest of the board. This allows you to tape the joint and add some jointing compound on top. This then brings the join up to the same level as the rest of the wall, allowing for a seamless finish.
If you tried the same method with a straight edge sheet you would end up with a raised area over each join.
This plasterboard can then be simply painted over without the need to skim plaster it.
FAQ’s
Do you need to PVA plasterboard before painting?
No, in fact, I would advise against it. This seems to be an old trade secret that is widely touted but that very few people in the know actually do. The idea is that watered down PVA gives the effect of a sealer.
I have found a mist coat of watered-down emulsion works much better. In fact, I could see the PVA giving quite a poor surface to paint onto.
Which side of the plasterboard should you paint?
There used to be a system where the grey side of a plasterboard sheet was for plastering and the white side was for painting. This seems to have changed recently and now the white side is commonly used for everything.
I always advise using the white side for painting. You may sometimes see a note printed on the plasterboard saying which side to use.
If you can’t see anything then try and contact your supplier as all plasterboard can be different.
Do you need to prime plasterboard before painting?
You don’t need to and as I have said above I advise using a mist coat of watered-down emulsion as your primer. Some people will say that primer is cheaper than regular paint so it makes sense to use a primer.
I can see the logic here and have no real problem with it, I just don’t like having to buy another tin of paint and have all the extra hassle of cleaning another set of brushes.
