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?

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!

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

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

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.

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

Waterproofing the 1/8" thick exposed plywood | Good Sam Community

MFL
Nomad II
Jun 26, 2020
Good to hear, congrats on a job well done.

When mine was new, I worked on it a little, most every day. My neighbors said they thought I bought a NEW one, so I wouldn't have to be fixing things. I replied, it is new, that is why I am working on it! :) Many don't realize, it's not the same as getting a new car or truck.

Jerry
RobWNY
Explorer
Jun 25, 2020
Flex Seal turned out great! All exposed wood is now sealed.
RobWNY
Explorer
Jun 24, 2020
Huntindog wrote:
Don't stop at just the edge. fill the gap between the wood and what appears to be metal tubing. This is why I thought a spray on product would work better... Gravity is gonna fight you trying to get it into the crevices

I'm going to squeeze some caulk behind the piece that isn't flush and clamp it until dry. The two pieces are butted up tight to one another so it's just that one small gap. After it's dry, I'll use the Flex Seal.
Huntindog
Explorer
Jun 23, 2020
Don't stop at just the edge. fill the gap between the wood and what appears to be metal tubing. This is why I thought a spray on product would work better... Gravity is gonna fight you trying to get it into the crevices
BurbMan
Explorer II
Jun 23, 2020
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
Explorer
Jun 23, 2020
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
Explorer III
Jun 23, 2020
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
Explorer II
Jun 23, 2020
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
Nomad II
Jun 23, 2020
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
Explorer
Jun 23, 2020
They still sell "undercoating" in spray cans at auto parts stores. Not a good as bedliner, but it will do in a pinch.

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Waterproofing the 1/8" thick exposed plywood

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