# Spongy Subfloor



## kevman

We bought our 2002 25RSS used about one year ago. Everything has been fine except about a month ago I noticed that the floor near the front door of the trailer is a little soft right at the entrance. I have walked around the trailer and don't feel this problem anywhere else. I notice the problem when pressing down with the heal of my foot. It feels a little spongy.

It feels like the subflooring is made of OSB and has gotten wet a few times. The trailer used to leak at the main cargo door by the bunk beds at the opposite side of the trailer, and I have since fixed the leak; but that does not account for the years it leaked before the fix.

Does anyone know what the subfloor is made of???? OSB or plywood. I am pretty handy but replacing the subfloor in part of the trailer is not my idea of fun. I am not even sure where to start. If it is bad flooring there is no way I could afford having it done at the shop. Way too expensive. Has anyone else had an issue like this to deal with??? Please let me know.


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## wolfwood

Can't help you with the flooring issue, but Chip replaced all of his linoleum and can probably give you a pretty good idea of what you'd find under there. See his thread at http://www.outbackers.com/forums/index.php?showtopic=7787

Hope that helps.


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## kevman

wolfwood said:


> Can't help you with the flooring issue, but Chip replaced all of his linoleum and can probably give you a pretty good idea of what you'd find under there. See his thread at http://www.outbackers.com/forums/index.php?showtopic=7787
> 
> Hope that helps.
> [snapback]104342[/snapback]​


 Thanks, I sent him an email. We will see.


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## Huskytracks

The floor is one continous piece of OSB. To repair it you'll have to get to the bottom and cut out the soft piece and replace it and then -brace the new piece in place. If it was me, I would just add another layer of 5/8 under the soft section and call it good.


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## SoCalOutback

I have fixed a couple of tent trailers with the rot doctor products:

Rot Doctor

They work great and a lot of the time you don't need to cut and replace large portions of the sub floor. In fact the repaired area is stronger then the rest of the floor in most cases.



Huskytracks said:


> The floor is one continous piece of OSB. To repair it you'll have to get to the bottom and cut out the soft piece and replace it and then -brace the new piece in place. If it was me, I would just add another layer of 5/8 under the soft section and call it good.
> [snapback]104488[/snapback]​


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## outbackgeorgia

I have the same issue with my 2003 21RS.
I did have a punctured water tank last year replaced under warranty, but I wonder how much water soaked into the floor.
I plan to pull up some flooring as the underneath is covered by a membrane in addition to the plastic underpan.

Outbackgeorgia


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## Chips

Sorry to take so long to respond but Iâ€™ve been replacing my step-tub and haven't been at the forum for awhile.

When I removed my linoleum to lay laminate flooring, I didn't have to cut into my sub-floor, but, I saw what it is like when I was replacing my tub because there is an opening in the floor by the drain P-trap. The sub-floor is two panels of 1/4" plywood with 1 1/2" Styrofoam insulation sandwiched between it. Under the bottom plywood is a black 1/16" membrane. I would think that if you had water problems the glue holding the sandwich together may have separated and the 1/4" plywood lost some of it's rigidity. Rather than disturb the top floor covering, I myself would probably reinforce the underside of the floor in the spongy area. If you use a large enough piece of 3/4" plywood you can screw it up through the membrane in several places and into the bottom existing plywood sub-floor. The screw would then extend partway into the Styrofoam sandwich and not penetrate through your top 1/4" plywood sub-floor. By using a large enough plywood under-patch, the weight would be distributed over a larger area like a snow-shoe. This is only my 2 cents but it's what I would try.

P.S. If you look at the hole for the pipes that comes up through the floor by your water pump, you'll see the sandwich sub-floor I'm talking about.


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## kevman

Chips said:


> Sorry to take so long to respond but Iâ€™ve been replacing my step-tub and haven't been at the forum for awhile.
> 
> When I removed my linoleum to lay laminate flooring, I didn't have to cut into my sub-floor, but, I saw what it is like when I was replacing my tub because there is an opening in the floor by the drain P-trap. The sub-floor is two panels of 1/4" plywood with 1 1/2" Styrofoam insulation sandwiched between it. Under the bottom plywood is a black 1/16" membrane. I would think that if you had water problems the glue holding the sandwich together may have separated and the 1/4" plywood lost some of it's rigidity. Rather than disturb the top floor covering, I myself would probably reinforce the underside of the floor in the spongy area. If you use a large enough piece of 3/4" plywood you can screw it up through the membrane in several places and into the bottom existing plywood sub-floor. The screw would then extend partway into the Styrofoam sandwich and not penetrate through your top 1/4" plywood sub-floor. By using a large enough plywood under-patch, the weight would be distributed over a larger area like a snow-shoe. This is only my 2 cents but it's what I would try.
> 
> P.S. If you look at the hole for the pipes that comes up through the floor by your water pump, you'll see the sandwich sub-floor I'm talking about.
> [snapback]105276[/snapback]​


Chips,
Thanks for your reply. That is some good information to know. At least it does not sound as bad as I had originally anticipated. I was hoping to come at the problem from the bottom rather than through the linoleum. Your thought about the glue letting go and the 1/4 inch plywood getting weak is probably right on the money. I have heard some slight cracking sounds if I push down real hard with the heal of my foot. And it is the sound you would get from cracking 1/4 inch plywood. Thanks for the input.


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## Chips

kevman said:


> Chips said:
> 
> 
> 
> Sorry to take so long to respond but Iâ€™ve been replacing my step-tub and haven't been at the forum for awhile.
> 
> When I removed my linoleum to lay laminate flooring, I didn't have to cut into my sub-floor, but, I saw what it is like when I was replacing my tub because there is an opening in the floor by the drain P-trap. The sub-floor is two panels of 1/4" plywood with 1 1/2" Styrofoam insulation sandwiched between it. Under the bottom plywood is a black 1/16" membrane. I would think that if you had water problems the glue holding the sandwich together may have separated and the 1/4" plywood lost some of it's rigidity. Rather than disturb the top floor covering, I myself would probably reinforce the underside of the floor in the spongy area. If you use a large enough piece of 3/4" plywood you can screw it up through the membrane in several places and into the bottom existing plywood sub-floor. The screw would then extend partway into the Styrofoam sandwich and not penetrate through your top 1/4" plywood sub-floor. By using a large enough plywood under-patch, the weight would be distributed over a larger area like a snow-shoe. This is only my 2 cents but it's what I would try.
> 
> P.S. If you look at the hole for the pipes that comes up through the floor by your water pump, you'll see the sandwich sub-floor I'm talking about.
> [snapback]105276[/snapback]​
> 
> 
> 
> Chips,
> Thanks for your reply. That is some good information to know. At least it does not sound as bad as I had originally anticipated. I was hoping to come at the problem from the bottom rather than through the linoleum. Your thought about the glue letting go and the 1/4 inch plywood getting weak is probably right on the money. I have heard some slight cracking sounds if I push down real hard with the heal of my foot. And it is the sound you would get from cracking 1/4 inch plywood. Thanks for the input.
> [snapback]105414[/snapback]​
Click to expand...

Here,s a photo of a cross section of the sub-floor

http://www.outbackers.com/forums/index.php...cmd=si&img=2981


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## kevman

Here,s a photo of a cross section of the sub-floor

http://www.outbackers.com/forums/index.php...cmd=si&img=2981
[snapback]105430[/snapback]​[/quote]

Wow what a crazy subflooring design. I could see where a soft spot could form when you are only using 1/4 inch plywood on the top. I could have never imagined the floor to look like this. The only way I could attack it at the bottom and provide support to the plywood would be to cut out the bottom piece and scrape away the styrafoam. I can't see me doing that. I may have to pull up the linoleum to fix it afterall. Thanks for the pics.


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## Chips

Just a thought you might want to think about. Maybe the problem is not water related. Maybe this trailer came from the factory with a spongy spot at the entrance. If it did, my thought would be that for some reason there is not enough Styrofoam insulation sandwiched between the Â¼â€ plywoodâ€™s. In my trailer, the floor doesnâ€™t feel spongy anywhere which leads me to think that this sandwich design is both lite and rigid. But take some Styrofoam out or accidental have it not form properly in an area and the floor would feel spongy. You might consider trying the following ( Just a suggestion as I am just guessing there is a lack of Styrofoam ):

From underneath, drill some holes up through the bottom plywood and through the Styrofoam to within about a Â½â€ to Â¼â€ below the top plywood. ( I have used a few oversized nuts slipped over the drill bit as a measured stop point.) Stick the long tube that comes with Spray Styrofoam Insulation ( comes in a can ) into each of the holes and give a blast of insulation. If there is a cavity, the foam will expand filling the cavity and hardening creating a solid sub-floor. Just my 2 cents worth.


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## kevman

Chips said:


> Stick the long tube that comes with Spray Styrofoam Insulation ( comes in a can ) into each of the holes and give a blast of insulation. If there is a cavity, the foam will expand filling the cavity and hardening creating a solid sub-floor. Just my 2 cents worth.
> [snapback]105551[/snapback]​


 Chips,
That is a very imaginative idea. I just might have to try it. Thanks


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## aplvlykat

How about doing it this way. Pick out some nice hardwood flooring or laminite flooring. Then trim back the linoleum to expose the subfloor. Then glue and screw down the edges of the new floor to the old and put moulding on to hide the screws. You now have a decorative entrance and a reenforced floor. Good luck, Kirk.


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## Trgreen2020

I have a 2013 Palomino solaire ultralight camper that has soft floor issues mainly by the slideout on both sides when I removed the linoleum I found out their was fresh water on the plywood floor. I had to remove most of the rotted plywood only to discover that one their is aluminum floor braces in the floor and two under the plywood their is styrofoam and under the styrofoam is another sheet of plywood. I thought may be using a liquid compound that flooring contractors use on house floors to fill in holes in old flooring before laying down sheets of 1/4 inch plywood to attach new linoleum then add some epoxy filler because of the styrofoam center may melt if I did not do it this way. What would you all do in my case? The slideout has rollers under it and has 2 tracks on both sides that the gears use to move the slide out in and out. I also thought their has to be a way to get access under the slide out with out pulling it out totally which for one person would be a pain in the butt. I also have to remove as much of the carpet as possible under the slide out because it was also drenched in water and the floor was rotted under it. I want to find a way that I can get this fixed so I can lay in laminate floor and still have full use of the camper.


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