Subfloor Repair Advice please for a newbie

[Mary Burris]

I friends, I am a new Airstream owner (62 Trade Wind). Over the weekend we removed the front gaucho for easier new flooring installation in the next week or so. I was vacuuming along the front wall (where a window or the seams above the rain guard) have been leaking and a small section of the floor collapsed down just by the vacuum tip touching it. It just crumbled. I then took my screwdriver to gently tap to find out how big a soft area I had. It is probably 6-8" wide by a foot or so, from the left wall curve along the front wall. Looks like this has gone undetected for years. I cut away the crumbly stuff and now have a hole exposing the belly pan. What is the best way to patch this?
Additionally, I have a very soft and springy area in front of the fridge area that I am not thrilled with leaving in that condition. It was suggested that I use bondo on the low spots and then seal the area (I am thinking of doing the entire exposed subfloor) with a marine grade paint or epoxy sealer in the attempt to waterproof or add at least a barrier for water to reach the original subfloor.
Any advice is appreciated...
Thank you,
Mary Claire in Sunny St. Petersburg, FL

[Belegedhel]

Start by checking your entire floor for rotten spots. Around the door, under and and behind the refrigerator, and all along the perimeter are the usual places the floor will rot. This will help you to decide whether you are looking at patching small areas, replacing entire sheets, or doing the entire floor. If you get lucky and only have a few small sections as you describe above, they can be patched.

To patch a small section, saw out a square section where you are back to solid floor, then install a piece of wood along each edge of the hole 3" or so wide underneath the existing floor so that it extends into your missing section by about 1.5". This becomes the "shelf" that will support your patch. Fix it in place with glue and screws. This is the technique that is described in the older Airstream maintenance manuals. I know there are plenty of folks who have stabilized rotting sections using some form of epoxy--I don't have a lot of confidence.

The "springy" area you describe might be rotty floor that is getting soft. It may also by a symptom of bigger troubles, ie., you may have a cross member underneath that has let loose on one side and is allowing the floor to move. Look for a row of screws in the subfloor indicating a cross member is underneath. If the floor is moving right over a cross member, then you may have some frame repair work to do as well.

good luck!

[mocus]

I signed on to the form this evening to report the same thing and I see you have already answered. I know the answer wasn't addressed to me but the information will do us both some good. On mine, I cut a 12x12" hole in the floor just inside the door, to the right, noticing the subfloor is about 3" above the aluminum shell. A thin insulation (aluminum backed) covering affixed on the underside of the plywood floor. Something that puzzles me is where the water is coming from. The rotting is between the top floor tile and plywood, working its way down through. I cannot see any indication of anything leaking. I have also spent a lot of time caulking in hopes to alleviate this problem, but I guess I missed something. Something I would like to know is with all the sweating inside, could that possibly be the culprit. The reason I ask is, the screws I have taken out of the wood on the inside are rusted, which indicates moisture.....

Another thing, I laid the tile less than a year ago and did not notice any problems. As far as I can tell there is no way for water to flow between the tile and plywood, indicating to me, the entire subfloor is getting wet. I would be very grateful for any suggestions.

[SuperTrouper]

Search the forums for a thread called "Rotten floor due to water leak!" My particular tale of woe starts on page 17 in mid February of 2013. Lots of pictures but the thread mostly pertains to newer trailers. Sorry I couldn't cut and paste the link but my IPAD does not offer the utility of my Safari web browser. Brad

[TG Twinkie]

It could be the door frame, the door gasket or seams above the area. Does the door close tight all the way around?

[65CV]

Stop the leaks right away!
If you're not sure how, have your local dealer pressure test.

[mocus]

Checked door and she is closing fine. Like I say, the dampness goes beyond 2 feet of the door wall, primarily just to the right of the door, 12", extending under the couch about 8". I'm a good distance from an AS dealer, but will check the closest. I just cannot understand how the water comes in, traveling between the tiles and floor, without the tile coming up. Tile adhesive still bounding very well. And another thing, we have only been in the rain once on our trips and I keep the trailer under my carport.

Eight or 9 months ago, I did detect a leak in the dry tank configuration and took the couch out, repaired leak, took up the vinyl, and put down vinyl squares. The floor around the tank was damp, and that was only place there was any evidence of leaking.

I have read somewhere on this forum individuals using some sort of dampness detector. I believe I will also look in that direction. Thank all of ya very much.