[Danny]

Alright folks,

I'm currently in the process of building myself a monster training facility in my back garden. All told it’s going to have about 15 sheets of marine ply on it – not cheap but vital if its to stand a chance against the Irish mizzle. I’m trying to work out how exactly to treat this wood to get the best out of it in the long term, and this is proving to be a bit of a minefield. The board is going to be covered by a proper roof or tarp, but I still want to protect it from the elements as much as possible. I near shat myself when I discovered the going rate for a sheet of marine ply.

Should I:
a)   Use a woodstain or decking oil on both the back and climbing surfaces of the board
b)   Use woodstain on the climbing surface and yacht varnish or exterior gloss on the back
c)   Use garage floor paint on the climbing surface and yacht varnish / gloss on the back
d)   Something else – if anyone has built something similar outside, how has it stood the test of time?
I’m punting for something non slippery on the climbing surface because I don’t want spinning holds.

Any help would be much appreciated, I want to make a decent job of it.

[slackline]

I know little about treating wood, but isn't this why you're using marine plywood in the first place?  Or is this in addition to implicit protection afforded by that grade of wood?

There are some threads in the forums about weather proofing outside, perhaps try trawlling through the board construction FAQs (failing that try the parent sub-forum).

[Probes]

A good quality primer and a couple of layers of standard ext gloss... as you would use on a window frame would prob be cheapest and best. Or paint pva all over it, quite a thick coating. Sounds a beast. 

[Danny]

It is in addition to the implicit protection afforded by the ply. As far as I can work out its still in the woods best interest to have some kind of external treatment. Boaty type people seem to go to town treating wood, even marine ply. Basically, if I'm going to spend 500 notes on ply alone I may as well spend 50 more and make it totally bombproof.

I think I'll punt for exterior gloss at this point - the same stuff I used to paint the box iron frame. As for the climbing surface side, gloss will be no good, so I wonder if anyone has used garage floor (non slip) paint? If not I'll just stain it and that'll do.

Cheers fellas.

[tomtom]

When I lived in Wales, my house was uber exposed (open view to sea & westerlies 1-2km away) - and Dulux mega supa 10 year guaruntee exterior gloss (applied with correct primer and undercoat) used to last 2 years at best. My neighbour used to use boat paint. No idea what it was really, except it was matt, and it's apparently designed to breathe a little bit. I think its the stuff you use to paint the cabin and other bits rather than the hull etc.. it was reasonably pricey..

I'd be tempted (however) to go for some sort of woodstain - that will seep into the wood nicely. I'd hate to have a woodie that had some uber slippy gloss finish. It may also be worth looking for any oils or other treatments (though this may not work well with ply as its got loads of glue in it..)... a bit leftfield, but what about creosote?

But if its under cover - and kind of exposed (the wind can get to it) then it'll probably last years just getting a bit damp now and then, and then drying off....

(I'll qualify the above by saying I have no technical knowledge of how all these perform etc.. )

T