Floor rot prevention?

[briheath]

I'm close to putting my floor back on my 65 tradewind. I will applying por 15 to the frame this weekend. My question is. Has anyone ever used a roofing undelayment on the floor? I'm considering applying the underlayment to the entire floor to help prevent future rot. My trailer seemed to have alot of rot around the entry door and the rear compartment door. It seems to me that this could be caused from the skin sweating in cold or cool nights. Condensation will be produced as air is leaking out of the camper and then the water runs down the walls and collects on the floor causing it to rot. I'm thinking of using the fabric type roofing underlayment not tar paper. I thought about using the ice and water barrier but am concerned about the smell when it gets hot in the trailer. The fabric will have less odor if any.

I will be posting pictures of my progress soon.

[jerrypeterma]

why not just use marine plywood

[richie rich]

In the sign business,MDO was used medium density overlay.This form of plywood was extremely resistant to water.Corocel,a newer pvc product in 4x8 sheets is totally water resistant.When I replace the floor in the '63 Safari with these products a dehumidifier will also be incorporated.MDO has no odor.

[Mrcrowley]

Originally Posted by jpeterman

why not just use marine plywood

I think that would be good but why not in heavy wet areas like the rear bath and around the front of trailer use even rubberized bed line type material. You can spread around where the floor meets the inside paneling and just apply like a foot back from wall . Another thing to do is make sure your belly has no holes and rot spots. and resealing the front and rear of trailer . I can see where towing while it is raining would be like a pressure washer on the trailer and the water could find a way into trailer.

[SteveH]

If I were replacing a floor in an Airstream, or even replacing the carpet in an Airstream, I would treat the plywood with CPES (Clear Penetating Epoxy Sealer) from here: Wood preservation, rot repair, and restoration using epoxy resin on boats, homes and log homes.

The stuff just works great!

[navyeod]

Thanks Steve, just what I was looking for. Just ordered 2 gallons. Was looking for a penetrating sealer before I covered my subfloor.

[PizzaChop]

I have used CPES on a boat transom and did treat parts of my floor in the Airstream with it and agree that it is a good product.

But the best way to avoid floor rot is to prevent leaks through regular inspections and scheduled maintenance. I'm convinced most rot/rust is the result of years of neglect by owners who are no longer vigilent (or never were.).

[Distantdrummer]

Originally Posted by briheath

on my 65 tradewind.
Has anyone ever used a roofing undelayment on the floor? I'm considering applying the underlayment to the entire floor to help prevent future rot. My trailer seemed to have alot of rot around the entry door and the rear compartment door.
The water runs down the walls and collects on the floor causing it to rot.
It seems to me that this could be caused from the skin sweating in cold or cool nights. Condensation will be produced as air is leaking out of the camper and then the water runs down the walls and collects on the floor causing it to rot.

Interesting hypothesis that I have never considered nor seen mentioned before.
However it seems that your premise would produce somewhat equal perimeter rot in all areas of the wall surround, and I don't think that is consistent with most of the reports.

On the other hand what could your layering of the floor hurt ? Nothing that I can think of.
I think Roofing Felt (tar paper) either 15# or 30# weight would do the same thing too. But because the c-channel is sometimes real tight to force the plywood into, I do not know how the top sheet would keep from bunching or tearing. I would agree that perimeter edges of plywood should definitely be treated or coated with something.

[Crusty]

There's some interesting information here Penetrating Epoxies - Test Results at the website of Progressive Epoxies.

I read this article and I used his formula and products to make my own penetrating epoxy to stabilize some water damaged OSB flooring (followed by an overlay of fiberglass mat with epoxy for strength) with good results.

[truckasaurus]

I'm in the middle of applying East system Marine epoxy to exterior ply for the floor. (I've added some aluminum powder from WEST to increase abrasion and moisture resistance).

I like the idea of extra protection but I'd be concerned about building up layers that moisture might get trapped in make things worse. Could you lay it down into wet epoxy maybe?

Not to go off on a tangent but I notice on mine that the box section that runs from the tongue back is open at both ends; I don't know the best way to limit the water ingress from this but it's on my mind. I'm thinking of shooting expanding foam or something at the forward end but it sounds a bit sketchy; any ideas?

[Brad Barnes]

marine plywood rots! Just like all other un treated wood . Treated green board pontoon deaking is better of the two, limited thickness avalable . We buy ours directly from a pontoon mfg. who buy to his spec. Sealing is a good idea but its the hole that you drill that lets water in and with a sealer or overlayment it's trapped. Now the process starts all over again . West system epoxy thined works well if build up along the edge is an issue you have to fit it first an allow for it. The hole or drilling issue every hole or screew has to be sealed ie; adhesive sealent. Same treated woods do not accept resin or epoxies well, bonding problems. You may be better off with a penetrating wood prservative that will soak in with a very wet coat.

Brad G&B Custom Marine Canvas Upholstery and Repair

04 Bambi Mid restoration R&R CS complete due to being rolled on it's side
All the fun I can stand!!

[Silvertwinkie]

I dunno if what the factory is doing will prevent rot, but clearly, they must feel that rot is happening on the edges. Airstream started coating the plywood edges sometime in 2005. Attached is a picture I took when cameras were still allowed on the production floor. You can see the black along the edges where the shell and wheel wells come into contact with the plywood. I don't recall what kind of coating it is, but I seem to recall it was similar in texture of that stuff that is used as spray on liner on pickup truck beds.....

[briheath]

I want to say thank you to everyone for all your great ideas. I like the use of a penetrating epoxy or the truck bed liner stuff. Since I have the shell removed from the frame I am thinking about running a bead of vulkum (i think i spelt it right) around the edge ( under the c-channel). Any additional information would be greatly appreciated.

Thank You
Brian
1965 tradewind twin/frame off restoration.