Diana likes to say it’s impossible to hijack this thread, but I’d like to try. What is the best way to paint or seal regular old lumber — not pressure treated, just cheap pine — against the elements? I’m making two septic tank covers with a square frame of 2x6s and a row of 1x8s for the top. They will sit atop a platform of regular red brick, i.e., no ground cotact. What’s the best way to seal the wood against the elements? Appearance doesn’t matter; I just want the wood to last as long as possible. Any suggestions? Thanks! PS: I live in the desert, with very hot, dry weather and a 6-week monsoon season. Moisture is not a problem, but unrelenting sun and heat could be.
I consulted my ‘resident expert’ and he said that your best bet to protect the plywood is to find yourself some WHITE paint (for the most reflectivity) that is house paint with the highest UV rating you can find.
Since you live in the desert, you probably should be able to find that locally because it would be pretty standard for house paint in your area.
My advice? Always find the OLDEST geezer working at the Hardware Store and ask HIM what to do. ;)
The only thing I know of to protect wood from the sun/UV is spar varnish. It needs to have the UV blockers in it.
It’s not cheap but there really isn’t much that can hold up to that kind of sun. Regular paint just doesn’t have quite the durability.
If you wanted paint, obviously a light color to reflect as much sunlight as possible, but a good house paint of floor/decking paint could work, too, but I doubt it’s going to be much cheaper than the spar varnish.
If the lumber is dried well I have used marine paint with great success.
Blurb; Use an oil based paint. Use an exterior primer sealer first. You could add some linseed oil but will have to wait longer for it to soak in and dry. After the primer has dried put a second coat of gloss exterior oil based paint, as indicated white is a good color. (You might have to search for it. The powers that be don’t like oil paints, bad for the enviornment etc.)
If you were in a really wet climate I might suggest weep holes on the bottom (normally in masonry walls) but its dry most of the year. Just make certain you do a good job painting the cut to size 2x6 frame surfaces (including the end grain) before you assemble. Remember that wood does expand and move and leave some space between your 1” x 8” decking planks. (Use galvanized screws to fasten. Less likely to rust off or back out. )
Good luck!