[ezrv]

I guess I used the wrong forum location in Camping (tips, tricks) - here is copy - I will try to remove the other post
painting treated wood? I have something to build with wood 2x4". I can obtain "treated" 2x4" beams from Home Depot, these look different compared to the non-treated.
The beams will be outdoors, direct sun and rain, ambient air temperature up to 40°C, termites.
I wonder if and why "treated" wood needs to be painted.
I can not see an advantage to painting, because the wood will be partly inaccessible for re-painting later, while heat, water and termites are all welcome all over.

If painting is required what kind of paint should I buy?
thanks

This inquiry is related to my lifting the roof A/C of a Class C motor home in this forum. You don't need to read the other thread, I think this one has the full set of questions.

 

[PhilnJill]

I would apply a primer and then paint the wood with a oil base paint. I copied this next bit of info from a website as to why you should paint or stain treated lumber.

Continued exposure to the weather/elements can allow the natural openings in the wood to crack and become larger. As a result, the wood will retain too much moisture leading to rotting, warping and insect damage. A staining or painting application will seal and protect the wood, avoiding these damages.

 

[edwinjd]

First, make sure that the treated wood is completely dried out. Sometimes, treated wood can be a bit damp. If it is, you need to first let it to dry completely out in the sun otherwise the paint will not adhere to it.

As for the paint and primer, I'd suggest to use acrylic-based ones instead of the oil-based ones. Oil-based tends to lock in any remaining moisture on the treated wood, and if it's not thoroughly dried out, it can still cause it to rot over time. Acrylic also tends to crack less than oil, at least from my experience.