Ugh - floor is soft in spots

[Merlinmurph]

Our TT is now 10 years old (we've had it for and the floor has some noticeable soft spots. One part near the rear is especially soft.

I assume this was caused by a water leak but I have seen no evidence of a leak. One possibility is the large LR slide since the soft spots are on that side. Another possibility is during winter when the roof has snow on it (no cover). Maybe?

Q: How is the floor constructed? I have no idea what is underneath the veneer fake wood plastic sheet on the top. What's there? What's involved in repairing?

We actually want to sell this TT and get a smaller one, but the soft floor would be an issue.

Thanks,
Murph

 

[Jackiemac]

@TonyL had a similar issue which he resolved...

 

[TonyL]

Murph, we've had soft spots on our floor but it was not due to water but abysmal construction.
Our floor is a sandwich is 1/4" ply 1 1/2" sheet polystyrene and another1/8" sheet of ply.
The sandwich is pressure glued in manufacture with an aluminum frame for strength.
The issue is the frame is 24" centre's and no cross frames over 72" so the floor flexes. Neither myself or the wife can be described as petite so the flexing allows the polystyrene to fracture which loses the sandwich strength.
We've had the same issue with our fifth wheel at home, only that didn't have ply but 1/8"plastic sheet.
I've reinforced the floor from below the trailer here, and cut back the floor covering and made a new frame on our fifth wheel in the UK.

 

[Rene T]

I had the same issue as Tony. What I did was dropped the belly so I could get to the bottom side of the soft spot. My problem was also just flexing because of poor support.
I cut a piece of 3/4” plywood the biggest size I could make it then screwed it up to the rv floor with 1000 wood screws. Well maybe not a 1000 but you get the picture. Make sure they aren’t too long. You don’t want them to penetrate the rv floor.
I then added support framing (floor joist) out of wood to also help support the floor.

 

[TonyL]

Rene beat me to it!
That's exactly what I did, but used 5/8" ODB. You will need to find the aluminum frame to screw to, or use the chassis cross rails.
Be advised, if you button joint any boards, be sure to glue them or the floor will squeak when you walk on it. The best part is you get to refit the undersheet nice and flat, not sagging like a wet sponge.
I also took the opportunity to fit decent supports to the fresh water tank to stop that sagging as well.

 

[Merlinmurph]

Abysmal construction on a TT?? Blasphemy!!

Thanks very much for your responses. I was fearing that it was definitely water damage and having to rip up the floor. Of course, I don't know for sure, but you guys give me hope.

I don't know if all trailers have this, but I have this thin layer of stuff (maybe coroplast??) screwed onto the bottom of my TT. I believe it's part of the "Glacier Package" (marketing boys gone amok) for cold weather. Is that what you mean by "belly", Rene? Anyways, I'd have to remove that to get access and see what's really going on. Hope the mice don't mind the intrusion.....

Thanks again for your help. I'll attack it in the fall. First, I have to order 1000 wood screws.

Murph

 

[TonyL]

The coroplast is the sheet under the trailer. I'd you're lucky it will be attached with TEK screws.
If like me you're unlucky, it's attached with nail pins into the chassis which have to prayed out.

 

[TonyL]

I used self drilling screws with 3/16" x 1" fender washers to secure the ODB to the frame.

 

[Rene T]

The coroplast is the sheet under the trailer. I'd you're lucky it will be attached with TEK screws.
If like me you're unlucky, it's attached with nail pins into the chassis which have to prayed out.

Tony, what are TEK screws? Mine was held on with self taping sheet metal screws with large fender washers. Made it real easy to remove.

Is that what you mean by "belly", Rene? Anyways, I'd have to remove that to get access and see what's really going on. Hope the mice don't mind the intrusion.....

Thanks again for your help. I'll attack it in the fall. First, I have to order 1000 wood screws.

Murph

Yes that’s what I mean. Mine is smooth on both sides but the center was very similar to the corrugating of a cardboard box.
Keep in mind, you may not need 1000 screws. 950 may be enough. Also, drill a clearance hole in the plywood so the screws only grip the rv subfloor

 

[TonyL]

TEK screws are self drilling hex head screws. I learnt the name from my Lennox days, as the units were held together by them.
And I only used about 300 screws of differing sizes and types. Didn't want to add too much weight.

 

[Merlinmurph]

Good point about the weight. I'll get titanium screws.

 

[Rene T]

Murf, please let us know what you find.

 

[Merlinmurph]

Murf, please let us know what you find.

I sure will, it's just going to be awhile, like Oct.