The video I was mentioning was the one you talked about here:

"This is how FR has repaired soft floors under warranty. Pilotpodder has a nice video of what they did in his case.  The original floor got its rigidity from being a laminated "sandwich".  That is no longer possible in your case so you will likely need more supports than you think under your new floor to compensate for that."

I tend to lean toward procedures and products used for marine applications since I used to have a wood/epoxy composite sailboat. For that, I used mostly 3M 4200 and 5200 polyurethane adhesive/sealants. 4200 if you want to be able to ever take things apart later, 5200 if you never do. That stuff is so strong you can hang a lead keel on with it. 

Not sure what you mean by video link?  I put a link to West Systems' instructions page in my last post, there are both some videos and text documents in there worth looking at. 

Thanks offgrid.  It's definitely been an adventure.  I ended up tearing up most of the bottom plywood bc it was so loose.  This morning, when I opened it up, it was the first time the smell wasn't overwhelming, so that's a good sign!  

Do you have any experience caulking rpods?  The seams are so slight, putting the caulk bead on there will be a delicate job.

Do you have a link the to the video you mentioned?

You might want to use an epoxy mix to fill the wood rather than off the shelf wood filler. That would bond better and resist future moisture and rot. West Systems has some good tutorials you can download.

Well, stage one complete.  I really didn't want to remove all the styrofoam, but after seeing how wet it was underneath in one section, I went ahead.  It was actually easy for most of it.  The lower plywood I left in place, except where it was coming up easilly.

What I found with mine, is that there are basically 6 sections if you look from underneath.  3 of those sections are not able to be seen from below bc of the clean, grey, and black tanks.  Then there are open  sections at the rear, in the middle,and in the front.  I'll be  putting some sort of support in those areas like you mentioned.  Not sure exactly what yet, but it makes sense what you're saying and how it's needed.  I found the foam at Lowes, and it's really inexpensive, but thickness isn't exactly the same.  The foam I took up measured  at 1 3/4", and Lowes only has 1/2, 3/4, and 2....so I'll have to go with the 2 or use several layers together to get it the same size. 

The front and rear were the most damaged by water--from the floor and one corner/side  ended up being pretty wet. I exposed the wall on those areas, and actually took off the back molding in the rear corner to let it dry further.

We're having a glorious week here in SC.  Cool temps, low humidity, and sunshine! I'll have to do some wood filler repair on the  exposed walls, as well put in new plywood on the inner back panel, and some sort of wall paper. That will be the easy part! 

The inside is now down to only a bit of framing around the hot water  tank and heater, and of course the fridge and bathroom areas.  Everything else is down to the waterproofing wrap!

I decided I need to recaulk those areas, and might as well do the whole thing it's really not that much more.

So next steps is scraping and resealing while the inside dries.  I'm definitely happy to be done with  the tear down, that part was not fun and felt like I just kept finding more and more wet areas.  Time to put it back together, and I'm actually excited now about the possibility of what the inside can look like now and being able to sleep in it again!

If it was me I wouldn't try to remove the lower plywood, just remove the foam and the weatherproofing and let it dry. I would assume that could take several months. As the weather cools the humidity will drop and you can add some heat, that will speed things up. If you take the time to let it dry thoroughly you won't need to worry about the inaccessible areas wicking water back into your repaired areas. 

When everything is dry I would add the outriggers and an additional plywood layer under the lower one, wrapped in new weatherproofing, caulked, and supported from underneath by outriggers and support rails extending between the frame rails. 

This is how FR has repaired soft floors under warranty. Pilotpodder has a nice video of what they did in his case.  The original floor got its rigidity from being a laminated "sandwich".  That is no longer possible in your case so you will likely need more supports than you think under your new floor to compensate for that.

Then new foam from above and a new top ply layer. 

So, rpod  floor update!

After a week or more of drying, I ended up taking out most of the wood from the inside.  It turns out not only did I have a leak at the rear window, but also some of the openings (the outlet by right wheel well, the shore power outlet).  

So, I have scraped up the top layer of all the plywood.  Pulled off part of the wall to expose the wet areas and start drying it out.  The humidity tester tool was crucial here, as it showed me where things were still damp where I couldn't see, thank you again Dennis! 

The worse area was in the rear storage, under the seat  where the table is in the 172.  I took up the sub floor, down to the styrofoam, and part of lower plywood next to the water proofing.  I see there are 2 places where I will need to get someone to weld in a few riggers.  The back area, and the very front. 

My concern now, is waiting for it to finish drying (slow but surely, I'm using a few small DC fans, and charging the battery as needed), and what to do about the lower plywood (next to the water proofing).  It seems like the entire lower plywood is WET!

I saw another post of a guy who works on boats who took all his floor out.  I've DM'd him, but he hasn't gotten back to me.  I want to know if he took out his fridge, etc...I can see how I could take out all the styrofoam and wood except for below the appliances.  Replacing the lower wood, and cleaning or replacing the styrofoam would not be that hard, but if I don't expose the wood by the water proofing below the fridge and under the bathroom, I'm worried that little bit of moisture left there will end up making this all happen again. 

Thoughts? Anything encouragement or guidance is appreciated! 

I'd guess that their epoxies are probably similar to the West Systems ones. I would check that whatever you use retains flexibility and is proven to adhere to damp wood. Don't know how polyurethanes would work in your application.  Let us know what you wind up using and how it works for you. 

Offgrid, any thoughts on this product as an alternative?

https://www.rotdoctor.com/products/cpes.html

Today I learned that awesome device exists!  That's awesome. 

My wife had the same idea about turning on the heater.  I think I'll try that for a few days.  I have 2 box fans going in it now, and a small dehumidifier going in it at night.  It's def drying out more! 

You might want to buy one of these. They're cheap and you might be able to just push the pins through the underlayment to check the moisture level in there. And to see if the top is getting dry too. Very handy tool. 

If the top ply layer is delaminating as it dries then it has basically lost all its structural strength. You can't remove all of it without also removing the interior walls and lifting up the sidewalls. so you will need to adhere/attach your new top plywood layer well to the existing damaged plywood so it can be a substitute. That will require getting things as dry as possible. which will take forever in South Carolina this time of year. Maybe try putting a heater in the rpod to accelerate getting the humidity out, or wait for lower humidity this fall/winter,  One nice thing about the g flex epoxy is that it adheres well to wood that is still a little damp. 

Great thank you all! 

Offgrid, what would you use to seal the water barrier if I drill through it to test for water? 

I like the idea of having a seal above it all if nothing else.  It's only a 172 so it's not a lot of space (6x17 really?).  I think it's going to take a lot longer to dry out than I first imagined.  As it continues to dry, the plyboard is breaking apart more and more in the really damaged area right up front where the bottom bunk would be).  Today I pulled some more out, and pretty easily got down to the styrofoam layer. 

So, best not to begin, but once begun better finish!  Read that some where years ago. I'm committed now!

I think I'll only need 'outriggers' in that front area.  I'll send more pics as I get it going.

It's important to note that it is a laminated sandwich assembly, and derives much of its strength from the adhesive bond tying the whole assembly together. If your floor has wet through, even if you dry it out, you won't be able to count on the floor being strong enough to support the walls or the center areas of the floor (any areas distant from the main frame rails). 

I doubt you can ever get rid of the small totally. Once everything is fully dried, if it was me I would apply a coating of West Systems g-Flex epoxy to the entire old floor surface to seal it up. Then add your new plywood on top of that. I once did that in a room in a house I remodelled where the previous owners left dogs to urinate and it worked for that smell. It's not cheap though. 

Keep in mind, when you sand or otherwise disturb the moldy plywood or substrate you are spreading mold spores into the air.  If there is sufficient humidity, they'll start growing again.  Also, if you are sensitive to mold, you will need adequate PPE when ever you are inside the trailer.

Thank you Lost and offgrid.  All good points.  Somehow, the floor isn't falling through at any point right now.  I have a dehumidifier running at nigh, and fans on 24/7.  I'm having to get the vinyl up in small chunks under the fridge and the bath/shower. I don't want to remove, nor do I thing I can remove those really.  From what I can tell, the layering on the bottom went

Vinyl floor/linoleum

paper

plyboard

foam

plyboard

black waterproof sheet

I'm wondering if that bottom plyboard is wet too? It's hard to tell, but the smell is horrible after removing the vinyl flooring.  I feel like I'll need to get rid of the mold I can see up top (I've read threads about people using everything from anti freeze, to expensive mixtures), sand sand some of the board, and then put some type of sealant down on top of that. Then put a layer of new plywood down on the open area (flooring not underneath anything).

Anyone have any experience with this:

Thank you offgrid.  Amazingly, the floor hasn't dropped and is overall in good condition considering.

I need to get under the shower and the bin where the hot water heater is to try to get the vinyl up there still.  I'm in the south, and my storage place doesn't have power so I'm using the batter to run a fan and small dehumidifier, and recharging the battery as needed....so it's slow going.  My current plan is once it's dry, treat the plywood with something to prevent more mold and treat the smell, and then put 1/8" plywood on top of everywhere I can.  Keep it like that for a season and see if i got all the leaks, and then put some floor down.  I'll be remodeling the kitchen area (probably taking out the sink and stove, as we usually cook outside anyways). 

But you have to start with a solid intact surface for the epoxy to stick to. The plywood in the rpod floor apparently does not use very water resistant adhesives so you will need to allow it time to fully dry and then see if the plywood is delaminating. Very likely it is, in which case it will be difficult to seal. 

I would also assume that the floor sandwich is no longer structurally sound and plan on adding "outriggers" to support the walls as some others here have done. Do that before sealing the floor on the interior. And then a new plywood layer on top of the existing sealed-up floor.

I'm sorry, I make fun, but it does ultra SUCK for you to be stuck in this situation. The R-Pod is essentially a floor on the frame, then the interior parts are installed, then the aluminum frame goes on then the roof. To install a new plywood floor complete, would mean doing the entire thing backwards. 

 My recommendation is to take it to a Forest River dealer with a big service department and see what they say about it. Who knows. Maybe a couple thousand and a month of labor.?  Keep us updated on solution or end result.

if the soft spot is somewhere else and not discolored then I wouldn't suggest removing the ceiling. You have enough on your hands without getting into that....

Good luck!

There is no good way that I'm aware of to replace the whole floor as is serves as the platform for construction of the whole trailer. It might help you to view a video of how rpods are constructed.