Can you use masonry paint on treated wood?

by Sam Wood | Last Updated: 26/05/2021

If you are building anything outdoors then you will probably be using treated wood. In the UK at least you commonly get either green treated or brown treated wood for outdoor use. The treatment helps to stop the wood from rotting quickly but still needs to be painted ideally. And you have landed here because you are wondering if it is possible to use masonry paint on treated wood. Well, I happen to have just constructed a brand new fence made from green treated timber, and when it came time to paint this fence I decided to paint it with masonry paint. So I have done all the experimenting for you, read on to see how it worked out.

If you are just looking at painting regular wood with masonry paint we have a great article here where we test lots of different wood types.

Fence ready to be painted

Fence ready to be painted

Here is the fence waiting to be painted. You can see the treatment in the featherboard, particularly the ones on the left-hand side. If I was to leave this treated timber it would slowly age to a silver/grey colour, like what you can see in the top right-hand corner of the background. The problem with this is that it would look uneven for quite a while until it is fully aged. It would also be less protected than a fence painted with good protective paint, such as masonry paint.

So how well did the paint go on?

Really well actually. Painting the treated wood with masonry paint was a breeze. The paint went on nice and easy, just like painting any wall with emulsion, to be honest. The coverage was really good, in fact I only needed one coat to fully cover all of the treatment in the wood. This is because masonry paint is quite thick, due to it needing to cover brick and stone usually.

Green Treated Featherboard being painted with masonry paint

Green Treated Featherboard being painted with masonry paint

The only thing you need to think about is getting the paint into all of the knots and uneven surfaces of the wood. This is a little more difficult than painting a smooth surface but to be honest it is not that difficult. Just put some paint on the end of your brush and push it into all the little cracks and gaps.

The final result

Green treated wood painted with masonry paint

Green treated wood painted with masonry paint

So here you can see the painted fence. I will remind you that this is just a single coat of masonry paint, look how well it has covered! This was a miss-match of all different colours of timber that now looks nice and uniform. The paint was touch dry within an hour so overall the process was really easy.

One great advantage of painting with masonry paint is that it is waterproof within one hour, obviously a key feature when painting outdoors in the UK! Because of this, you don’t need to worry too much about the weather as long as it is not actively raining as you are painting.

What paint did I use?

The paint I went with was SandTex ultra-smooth. This is crucial, you don’t want textured paint on wood unless you are really after the textured look. The smooth is just like an emulsion really so nothing to worry too much about. SandTex is probably the most popular masonry paint in the UK, you can find it everywhere. Any of the big DIY stores will probably have it in stock, or you can even buy it online from Amazon.

The colour used here is mid stone, I really like this colour for wood. It still looks quite natural while being a nice bright colour.

What I Used!
Sandtex masonry paint ultra smooth. 5 Litres
£27.83 (£5.57 / l)
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09/23/2021 04:34 pm GMT

6 Month Fence Update!

For those of you keeping track, it’s now been six months since the fence was painted with masonry paint (give or take a few weeks). So it’s time to check back in with an update and let you all know how the paint is getting on, I know you can’t wait!

Six Month Test Update!

Six Month Test Update!

As you can see the fence still looks just as good as the day it was painted. So that’s the summer over with, now time for the real test, a Northern English winter. Check back next year for another instalment in this thrilling saga!

What is treated wood?

Normally treated timber, at least in the UK, comes in two forms. There is green treated timber and brown treated timber. Green treated timber can often look quite natural but with a green tint. Brown treated timber however is commonly a very dark brown.

Green treated wood

This wood has been pressure treated to help it last longer in exterior use. The chemicals used in green treated wood have copper in them. It is then this copper which reacts with the sap in the timber and also the oxygen in the air, this then creates the green colour you see on the treated wood. The colour often varies between batches. This is illustrated perfectly on my new fence up at the top of this post. Some of the timber is really green whereas other parts look quite natural.

This wood has all had the same level of treatment, just different batches turn out different colours. This is why treated timber is nearly always painted or stained to make it more uniform.

Brown treated wood

Brown treated wood goes through the same process as green treated wood. The only difference is that a brown dye is added to the mix. That is the only difference between the two. The brown dye makes the wood darker and in theory more uniform, it doesn’t add any extra protection.

I saw it makes it more uniform in theory as I have often found brown treated wood to be just as much of a miss-match of colours as green treated wood.

Because of the extra step involved with creating brown treated wood, it is usually a little more expensive than green treated wood. it can often be really dark, so if you are planning of painting it a light colour this could be a disadvantage, on the flip side of this, however, if you are planning on painting it dark this could be an advantage.

Learn More About Masonry Paint

This article is part of our masonry paint section, learn more about masonry paint with the following articles:

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Wood by name, wood by nature. I am a fully qualified, time-served, award-winning joiner with an NVQ Level 3 in Carpentry and Joinery as well as an HNC in Construction. Beyond my joinery qualifications, I have also earned a degree in building surveying. I believe these qualifications make me perfectly positioned to provide expert advice on many different areas of DIY as well as share all of the tips I have picked up in over a decade working on building sites!