Sealing underside of floor

[GarySaunders]

Just wondering what people are using for the underside of the floor? I was thinking Rhino bed liner or flexseal, any thoughts on this or is there a better product out there?

 

[gearsoup]

Tony (wrote a book on tear drop building) recommends simply using epoxy to seal it, and I'll be doing the same this weekend. You could apply a paint over it as well if you prefer, but will need to use a primer meant for epoxy/fiberglass.

 

[Tom&Shelly]

FWIW, we used epoxy on the underside of our tear five years ago, and it still looks fine.

Tom

 

[Tony Latham]

As mentioned, I argue for epoxy. It soaks into the wood and plasticizes it. Raka makes a good product and isn't too expensive. Buy their pumps.

Some will argue for roofing tar, but this isn't 1938, and you don't want to end up in the La Brea tar pit.

Tony

 

[S. Heisley]

I used epoxy (CPES) on both sides of my deck/floor. What I was told by the Rot Doctor people is that if you use epoxy, you should wait a couple weeks before you coat over it with anything because epoxy needs to "out-gas" for a while. I used spray undercoating from the auto parts store on the underside and a water based polyurethane over the epoxy on the inside but I did wait several weeks for the epoxy to out-gas before I did that. I have had no problems with the overcoating on either the top or bottom side of the deck/floor and it has been on for years.

Remember to coat the edges of the plywood with the epoxy as well as the flat surfaces as those places are the most vulnerable to wicking moisture.

 

[working on it]

I used "the Mix", a polyurethane (I used oil-based) & paint thinner mix, on my floor's topside (as well as on all exterior surfaces, except the bottomside of the floor), and used Herculiner (IIRC) spray bedliner there, as undercoating.

The ease of using the spray on the bottomside, done after all the topside structure was completed, made it a no-brainer. And, if you need to drill a hole thru the floor, or suspect that there's rock damage underneath, you can quickly repair and waterproof it again in seconds. I carried a spare can with me on all trips.

 

[gearsoup]

As mentioned, I argue for epoxy. It soaks into the wood and plasticizes it. Raka makes a good product and isn't too expensive. Buy their pumps.

Some will argue for roofing tar, but this isn't 1938, and you don't want to end up in the La Brea tar pit.

Tony

How many coats do you go with, and what was the process like? In your book, I see you've got a roller and paint pan; do you mix them in the 12 oz cups and pour into the pan, dip the roller and go to town, or did you mix in cups, pour directly on surface and then use the roller?

Oh wait. That image is for the poly coat on the topside. So pour directly and use the squeegees sounds like the approach

 

[Tony Latham]

That image is for the poly coat on the topside. So pour directly and use the squeegees sounds like the approach

Yep. Small batches, or the goo will go off in the cup. Lots of time once it's unconfined.

Tony

 

[TimC-TNT]

...

Some will argue for roofing tar, but this isn't 1938, and you don't want to end up in the La Brea tar pit.

Tony

Yep, that would be me. Four TDs with black jack and no problems since 2016! Sorry Tony, sometimes the old ways work just fine. : )

 

[DJ Davis]

I used Henry's fibered roof coating. I built the frame/deck of the camper, flipped it upside-down, painted it with the coating, let it set for a few days, then flipped it back over and set it in place on the trailer frame. It's been six years on the road now. I periodically crawl underneath the camper and check the coating for nicks/gouges/etc, as well as ensure the bolts holding the frame/deck to the trailer. So far, so good <knocks on wood>....

 

[Tony Latham]

Yep, that would be me. Four TDs with black jack and no problems since 2016! Sorry Tony, sometimes the old ways work just fine. : )

I get that. I just don't want to end up in marriage counselling or stuck in the black goo. Forever.



Tony

 

[halfdome Danny]

I cover both sides of the floor with plastic laminate (Formica) . Just contact cement it like a counter top and it’s there forever. My current TD is 10 years old and the floor looks great. If you know of a wholesale store like EB Bradley you can get discontinued colors for almost nothing. Danny

 

[Big Johnson]

As mentioned, I argue for epoxy. It soaks into the wood and plasticizes it. Raka makes a good product and isn't too expensive. Buy their pumps.

Some will argue for roofing tar, but this isn't 1938, and you don't want to end up in the La Brea tar pit.

Tony

Tony I just put 3 coats on my outer floor or base layer this past week. I put on a good coat of MAS marine epoxy waited on it to dry then sanded it then two more coats including the edges of the plywood.

 

[Tony Latham]

I just put 3 coats on my outer floor or base layer this past week.

That'll do it, for sure.

Tony

 

[gearsoup]

Yep. I did two good coats of Raka epoxy, some light sanding, and then followed it up with spray on bed liner.

 

[Big Johnson]

Yep. I did two good coats of Raka epoxy, some light sanding, and then followed it up with spray on bed liner.

I don’t think I’m even gonna use bed liner over the epoxy. The marine epoxy itself imo will be sufficient.

 

[Tony Latham]

I don’t think I’m even gonna use bed liner over the epoxy. The marine epoxy itself imo will be sufficient.

The epoxy under my cabin looks fine after six years.

Tony