T&G boards project coming up

[charles mathieu]

Hi ! When sitting on the patio, I can see the trusses and plywood of the patio ceiling so I'm planning to install tongue and groove boards to cover that. Since the boards will never get wet from the rain, is it okay to leave the boards unfinished ? I'm in Quebec so we do have a wide range of temperatures but my thinking is that as long as the wood remains dry, no finish should be ok, am I right ?

[Dan Hahr]

If you want them to stay clean and nice looking, then no. Dust and spider webs will need to be removed and it’s hard washing bare wood. Seal them with a good exterior varnish. I sprayed mine with Sikkens Proluxe window and door.
Dan

[Andrew Hughes]

What wood are you planing on if it’s just some white pine you might want to treat it.
To keep bugs from eating it.
But I don’t see why water would hurt I power wash my deck if I stay in one spot too long it will make the wood furry. It doesn’t seem to hurt it ,my deck is Port Orford cedar.

[charles mathieu]

Yes it's gonna be white pine but do bugs really eat that ? Which kind ?

[Steve Rozmiarek]

I did this ceiling last week, it's pine car side, I sprayed poly on it. I would put something on it to slow the aging down a little, otherwise it'll yellow pretty quickly. It still will with the poly, just a lot slower.
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[Al Launier]

It may not get rained on, but humidity and significant outdoor temperature changes "work" the wood and will eventually take its toll. I would recommend the use of spar varnish even if it's not exposed to the sun's UV, it'll stand up better than regular polyurethane varnish. Minwax Helmsman Spar Urethane should work well.