Waterproofing the 1/8" thick exposed plywood

[RobWNY]

On the inside wall area of the outside kitchen, pass though storage compartment and propane tank areas of my 5th Wheel, there is exposed plywood or paneling type material. The most concerning would be where the propane tanks are mounted because it's open underneath and spray will get in there if traveling when it's raining or there's wet roads. Sooner rather than later it will rot. I'd like to avoid that before it starts. Any ideas what I should do to protect it?

[BurbMan]

I was going to recommend Flex Seal as well. I had some framing under the slide in our TT that was wrapped with Darco...water got in, couldn't get out, and the wood rotted. When I rebuilt the floor I sprayed the replacement lumber with Flex Seal and it's help up great for 7+ years.

[RobWNY]

I decided to take a combined opinion approach. I bought a pint can of Flex Seal Liquid and will be painting it on. Hopefully it will last since it won't be exposed to UV rays and weather unless as I mentioned I'm traveling down the road during rain. It's an inexpensive repair and I can always go over it each year.

[CapnCampn]

I was going to suggest brush on polyurethane or some sealer like that, but I think MFL's suggestion of painting it would be just as good. It seems to work on house siding, right?

CC

[jdc1]

Why not use duct sealant? It's thick, sticks to ANYTHING, pliable (stretches), and weatherproof. Brush it on. Water clean-up. I used under my trailer where the tire blew a hole in my heater ducting. It holds up WELL.

[MFL]

I had a few unfinished plywood edges, a bit thicker than that, underneath my propane and pass through areas, that I just primed/painted. It has stayed sealed, no issue for years. I used a brush, so no mess or over spray.

Jerry

[STBRetired]

They still sell "undercoating" in spray cans at auto parts stores. Not a good as bedliner, but it will do in a pinch.

[Huntindog]

Ouch. That is not good.
I think the best way is to have it and rthe surounding area sprayed with bedliner.
Next best would be the DIY bedliner in a can. I have done a wood floor in a cargo trailer with it, and it worked great,,, But since you are working upside down, I think it would be hard to do a good job. Perhaps they make that stuff in a spray can now? Whatever you do, wear PPE! eyes, and breathing protection!