found soft spot in floor

[isonychia]

Hi,

We purchased a used travel trailer about 2 years ago.

Unfortunately, this year we found a soft spot in the floor.
It's about 12" x 12".

I have inspected the roof, slide outs etc many times and never saw any signs of failing seams etc. I obviously missed something.

The one thing we did notice upon opening the trailer for the season is it leaked inside from the AC unit.

The TT sits in a campground and never moves. We use it from April-July.

I was hoping for some guidance here.

I know I have to figure out the leak and do the repair. The repair is going to be difficult. I am skilled at carpentry and construction, so it's not the process that will be hard (I'm sure it will not be easy). It's the fact that the location is not close so I need to bring all my tools and TRY and anticipate what materials I will need. There is a local lumber yard so thats a bonus.

I guess I will start with the leak.

The AC unit is more towards the front middle of the trailer. The soft area is near the refrigerator and bathroom, near the back of the trailer.

Once I fix the AC seal/leak, I don't know how to track down the source of the leak that caused the soft spot. At this point I am assuming it's a roof leak or something in the bathroom. I know the water heater would leak into the bathroom through the drain plug FLANGE. So when I would reseal the anode rod or release the pressure after winterizing, the water runoff would enter the trailer through the flange. The water heater itself does not leak. (I don't think)

My idea is the following.

Can I remove the boards that seal up the undercarriage of the trailer and access the damage from there? I figure this will allow me to see the extent of the damage without tearing up the linoleum, carpet and removing the dinet couch etc. I also figured it would help me follow the path of the damage and maybe find the source/origin of the water entry.

I can only assume how the TT is built. I assume when I remove the undercarriage skin, I will see 2x4 type framing (not sure framing dimensions on a TT), insulation, pipes, wires and the subfloor. Does that sound right?

I have a bunch of other questions but I don't want to add too many at once.

Thanks,
iso

[rbpru]

The real question is have you stopped the problem. The second question is, is the soft spot and annoyance or something worth tearing into?

Only you can answer that.

Good Luck

[westend]

Lynnmor wrote:

westend wrote:
You will need to gain access from underneath the trailer. Remove a section of belly covering, perform the repair, and reinstall covering. I'd bet you will find a bit of wet insulation and moldy framing from the leak.

I would probably go the opposite way. Pull the shower surround and base, then build it back up like it should have been. The shower floor is a marginal piece of junk and can be replaced this way.

That may certainly be a better method. Hard to say without images of the shower and drain plumbing. My drain connection for the trap underneath the shower pan is accessible from underneath. If there are glass panels and doors involved, it may be less time consuming to operate from underneath if it is only the drain fittings that are loose.

[CavemanCharlie]

Lynnmor wrote:

westend wrote:
You will need to gain access from underneath the trailer. Remove a section of belly covering, perform the repair, and reinstall covering. I'd bet you will find a bit of wet insulation and moldy framing from the leak.

I would probably go the opposite way. Pull the shower surround and base, then build it back up like it should have been. The shower floor is a marginal piece of junk and can be replaced this way.

I might go a third way. He says that he can see the problem but, there is a obstacle in his way to get leverage on it. I would probably take a hand saw and try to cut the obstacle out of the way and then after fixing the problem try to rebuild it somehow.

I will admit that my fixes usually work for me but, they do have a certain "Red Green Show" style to them. The only trouble I get into is when I sell something and the next person calls me up after and asks what the heck is going on.

[Lynnmor]

westend wrote:
You will need to gain access from underneath the trailer. Remove a section of belly covering, perform the repair, and reinstall covering. I'd bet you will find a bit of wet insulation and moldy framing from the leak.

I would probably go the opposite way. Pull the shower surround and base, then build it back up like it should have been. The shower floor is a marginal piece of junk and can be replaced this way.

[westend]

You will need to gain access from underneath the trailer. Remove a section of belly covering, perform the repair, and reinstall covering. I'd bet you will find a bit of wet insulation and moldy framing from the leak.

[CavemanCharlie]

isonychia wrote:

westend wrote:
Meh, small spuds. I have been remodeling and into different spaces for years. Replacing a few panels of flooring and pulling the wet insulation is easy. I would assume that pulling the under belly covering is one of the remediation steps. You want to make sure that any floor framing and flooring sheets are dry. Just from your descriptions, maybe it's possible to cut the fabric at the wall joint where it is wrapped, save the material, and reinstall it when done. Since this RV is parked, you won't have to worry about road grime and water entering while you're working on it.

How you schedule the completion of your project is up to you but I'd give it some thought and see how and what you need to transport to make it all better than new. In my work truck, I haul a complete set of tools and various hardware/fasteners so my workshop travels with me. If you're short on tools to make the job go easy and fast, seek out a friend or guy that has them for loan. Maybe you can even talk him into helping. If I was closer...

Here are a few things I'd plan to do: Find where the water is coming from. Remove bad flooring sheets. Remove any wet or compacted insulation. Treat wet spaces in floor framing with bleach/water. Dry floor and framing with fans. Install foam board in place of spun fiberglass. Replace OSB with floor rated plywood. Inspect and tighten all plumbing bits.

I'd very much suggest to do the interior pressure test. For me, nothing would be worse than repairing a floor only to find that there are other leak entrances, undiscovered. If I had to rent a blower to do it, I would.

Good luck with the floor. It will go quickly, once you start.

Well I think I found the source of the leak.
The shower drain was leaking.

Now the problem is how to replace the drain.

I purchased a new drain but I cant reach the nut that compresses the seal to the underneath of the shower pan/drain hole.

This is a corner shower with a rectangular access panel. The problem is there is an elevated floor board that the shower pan sits on. That is in the way of accessing the nut. I can reach the nut but it's impossible to gain any leverage to turn it.

We tried a drain wrench, but the drain strainer was corroded and broke.

I looked under the trailer and of course there is no access panel in the underbelly.

Again, a totally idiotic design.

The only thing I can think of is to cut a piece out of the floor board the pan sits on to expose the nut or go under the trailer and cut an access panel out of the underbelly.

The shower pan is sitting on a few pieces of 2x4 with the "floorboard" on top. It's really 2 sheets of luan with foam in the middle.

Thing is, how did the manufacturer expect anyone to service it?

Am I missing anything?

iso

They were not built to be serviced. They are just slapped together as quickly as possible. You will have to figure out how to make your own service hole/

[isonychia]

westend wrote:
Meh, small spuds. I have been remodeling and into different spaces for years. Replacing a few panels of flooring and pulling the wet insulation is easy. I would assume that pulling the under belly covering is one of the remediation steps. You want to make sure that any floor framing and flooring sheets are dry. Just from your descriptions, maybe it's possible to cut the fabric at the wall joint where it is wrapped, save the material, and reinstall it when done. Since this RV is parked, you won't have to worry about road grime and water entering while you're working on it.

How you schedule the completion of your project is up to you but I'd give it some thought and see how and what you need to transport to make it all better than new. In my work truck, I haul a complete set of tools and various hardware/fasteners so my workshop travels with me. If you're short on tools to make the job go easy and fast, seek out a friend or guy that has them for loan. Maybe you can even talk him into helping. If I was closer...

Here are a few things I'd plan to do: Find where the water is coming from. Remove bad flooring sheets. Remove any wet or compacted insulation. Treat wet spaces in floor framing with bleach/water. Dry floor and framing with fans. Install foam board in place of spun fiberglass. Replace OSB with floor rated plywood. Inspect and tighten all plumbing bits.

I'd very much suggest to do the interior pressure test. For me, nothing would be worse than repairing a floor only to find that there are other leak entrances, undiscovered. If I had to rent a blower to do it, I would.

Good luck with the floor. It will go quickly, once you start.

Well I think I found the source of the leak.
The shower drain was leaking.

Now the problem is how to replace the drain.

I purchased a new drain but I cant reach the nut that compresses the seal to the underneath of the shower pan/drain hole.

This is a corner shower with a rectangular access panel. The problem is there is an elevated floor board that the shower pan sits on. That is in the way of accessing the nut. I can reach the nut but it's impossible to gain any leverage to turn it.

We tried a drain wrench, but the drain strainer was corroded and broke.

I looked under the trailer and of course there is no access panel in the underbelly.

Again, a totally idiotic design.

The only thing I can think of is to cut a piece out of the floor board the pan sits on to expose the nut or go under the trailer and cut an access panel out of the underbelly.

The shower pan is sitting on a few pieces of 2x4 with the "floorboard" on top. It's really 2 sheets of luan with foam in the middle.

Thing is, how did the manufacturer expect anyone to service it?

Am I missing anything?

iso

[westend]

Meh, small spuds. I have been remodeling and into different spaces for years. Replacing a few panels of flooring and pulling the wet insulation is easy. I would assume that pulling the under belly covering is one of the remediation steps. You want to make sure that any floor framing and flooring sheets are dry. Just from your descriptions, maybe it's possible to cut the fabric at the wall joint where it is wrapped, save the material, and reinstall it when done. Since this RV is parked, you won't have to worry about road grime and water entering while you're working on it.

How you schedule the completion of your project is up to you but I'd give it some thought and see how and what you need to transport to make it all better than new. In my work truck, I haul a complete set of tools and various hardware/fasteners so my workshop travels with me. If you're short on tools to make the job go easy and fast, seek out a friend or guy that has them for loan. Maybe you can even talk him into helping. If I was closer...

Here are a few things I'd plan to do: Find where the water is coming from. Remove bad flooring sheets. Remove any wet or compacted insulation. Treat wet spaces in floor framing with bleach/water. Dry floor and framing with fans. Install foam board in place of spun fiberglass. Replace OSB with floor rated plywood. Inspect and tighten all plumbing bits.

I'd very much suggest to do the interior pressure test. For me, nothing would be worse than repairing a floor only to find that there are other leak entrances, undiscovered. If I had to rent a blower to do it, I would.

Good luck with the floor. It will go quickly, once you start.

[isonychia]

westend wrote:

Thanks for the info westend.

I already ordered 3 rolls of the tape and a new ac seal. I hope it's the 14x14 one.

To clarify. If my floor is composite, foam sandwiched between 2 sheets of plywood, is that simply sitting on top of the floor joists with the lower layer of plywood fastened to the floor joists?

I think my trailer is simply OSB with regular fiberglass insulation. One of the exterior hatches has a seal problem and water has gotten inside. When I was trying to fix it, (adding thicker foam weather stripping) I pulled back the carpeting and I could see the subfloor was simply OSB with fiberglass insulation underneath. So I assume thats how the rest of the floor is.

I also assume R13 insulation is what I should purchase to replace the existing?

A few more questions.
When I remove the sections of flooring how bad is it if I leave the sections under the refrigerator and kitchen sink if there is deterioration on those panels. Assuming I find the source of the leak and stop it?

There is a wall for the bathroom. I am not sure if I will be able to remove the plywood subfloor from under those wall sill plates. I figured I would cut around it if I need to. Is that ok?

Thanks,
iso

Different Mfgs have different ways of installing the floor. A composite panel floor is typiclly attached in a few spots to frame brackets, it is usually not installed like a typical frame-built floor, i.e. attached on 16" centers into joists. You may have a more conventional floor with wooden floor joists and OSB installed as the floor sheathing. The latter is easier to repair.

The under floor insulation will be your call as to refitting the same, installing new, or upgrading to an extruded polystyrene foam board. The price of insulation is so cheap that any of the three or combination of, will serve for you. My suggestion is that you put as much in as possible. More insulation = more comfort and less heating and cooling costs.

You can certainly cut the floor at locations that are easy to reach with conventional tools. You can always add small wood blocking or joist ledgers into the floor when reassembling your work. Fortifying those areas with wood placed into the "sandwich" will only make the floor stronger.

I cut my single 5/8" plywood floor back 6" from the exterior walls in most locations. This allowed me to install foam board pieces underneath the wall plates and under that 6" of plywood floor. When reassembling, I installed a piece of lumber underneath the cut line to support both pieces of plywood, the one remaining (6") and the larger piece removed. In one area, where there was extensive wall rot and the plywood was non-existant under the wall plate, I chipped out the bad plywood, cut nails and screws in the way with sawzall and small grinder, slid the new plywood under the wall, and reattached through a sound wall plate.

FWIW, I spent two weeks, close to 80 hrs. cutting and fitting foam board into wall and ceiling cavities. No cavity was plumb or straight so each piece was measured and custom cut, also allowing for electrical boxes and wire runs. I saw pink spots for a few days, lol. The end result of my efforts was a trailer that is like no other when seated inside. There is very little exterior noise (if windows and doors are shut) and it takes quite a bit less heat or A/C to get comfortable. Insulation in trailers rules, the more you can get into the trailer and the precision that you use if using foam board, pays big dividends going forward.

Good luck on the floor, once you dive into it, you will understand what needs to be done.

Well I removed the vinyl sheet and as expected it was worse than the small soft spot we found.

It seems, based on the darkness of the floor, the leak is in the bathroom near the shower. From there it has radiated outwards.

So the section I need to replace is the bathroom and 4 feet into the living room. When I removed the OSB flooring in a small spot I saw the underbelly was holding most of the water and the insulation was wet.

There is no foam. Just 3/4 OSB with paperless fiberglass insulation.

Since the trailer was closed for the winter and no water was being used I can almost be sure it's a structural leak and not a plumbing problem.

I checked the entire back half of the trailer and couldn't find anything that could cause it. Ladder, lights, shower compartment, skylight, seams etc. There was a small crack in the fiberglass shell near the bottom of the trailer skirt. If it is above the line of the subfloor that may have caused this, but it is on the wrong side and it's on the downslope of the trailer pitch towards the slide-out. I put lap sealant on it anyway.

If I have time I will attempt that pressure test. For now the plan is the following.

Tape every seam on the roof. Caulk all vertical seams with Proflex. Is Proflex what I should use for the vertical seams? Most seem to have that butyl tape.

Cut as much of the old floor out as possible and replace with new plywood. I would love to remove the entire bathroom, but I don't have the time to remove the shower stall, sink and cabinet. It would be the right way to do it, but it's a 2 hour drive to the campsite and it's too involved in a remote location like that.

I don't know how I am going to address the wet insulation. I looked at the under belly and it looks like the edges are tucked under the side frame of the trailer walls. So I am not sure yet if it will be difficult removing them.

I can remove the insulation from above, but I am sure the insulation on the other side of the trailer is wet too. I am hoping taping everything will stop this leak and then the insulation I cant get out will dry out.

Any thoughts besides I'm screwed...LOL.


iso

[2012Coleman]

Check the seal and caulk around the entry door. In-laws had this problem, and no one thought it could be the door seal.

[westend]

Thanks for the info westend.

I already ordered 3 rolls of the tape and a new ac seal. I hope it's the 14x14 one.

To clarify. If my floor is composite, foam sandwiched between 2 sheets of plywood, is that simply sitting on top of the floor joists with the lower layer of plywood fastened to the floor joists?

I think my trailer is simply OSB with regular fiberglass insulation. One of the exterior hatches has a seal problem and water has gotten inside. When I was trying to fix it, (adding thicker foam weather stripping) I pulled back the carpeting and I could see the subfloor was simply OSB with fiberglass insulation underneath. So I assume thats how the rest of the floor is.

I also assume R13 insulation is what I should purchase to replace the existing?

A few more questions.
When I remove the sections of flooring how bad is it if I leave the sections under the refrigerator and kitchen sink if there is deterioration on those panels. Assuming I find the source of the leak and stop it?

There is a wall for the bathroom. I am not sure if I will be able to remove the plywood subfloor from under those wall sill plates. I figured I would cut around it if I need to. Is that ok?

Thanks,
iso

Different Mfgs have different ways of installing the floor. A composite panel floor is typiclly attached in a few spots to frame brackets, it is usually not installed like a typical frame-built floor, i.e. attached on 16" centers into joists. You may have a more conventional floor with wooden floor joists and OSB installed as the floor sheathing. The latter is easier to repair.

The under floor insulation will be your call as to refitting the same, installing new, or upgrading to an extruded polystyrene foam board. The price of insulation is so cheap that any of the three or combination of, will serve for you. My suggestion is that you put as much in as possible. More insulation = more comfort and less heating and cooling costs.

You can certainly cut the floor at locations that are easy to reach with conventional tools. You can always add small wood blocking or joist ledgers into the floor when reassembling your work. Fortifying those areas with wood placed into the "sandwich" will only make the floor stronger.

I cut my single 5/8" plywood floor back 6" from the exterior walls in most locations. This allowed me to install foam board pieces underneath the wall plates and under that 6" of plywood floor. When reassembling, I installed a piece of lumber underneath the cut line to support both pieces of plywood, the one remaining (6") and the larger piece removed. In one area, where there was extensive wall rot and the plywood was non-existant under the wall plate, I chipped out the bad plywood, cut nails and screws in the way with sawzall and small grinder, slid the new plywood under the wall, and reattached through a sound wall plate.

FWIW, I spent two weeks, close to 80 hrs. cutting and fitting foam board into wall and ceiling cavities. No cavity was plumb or straight so each piece was measured and custom cut, also allowing for electrical boxes and wire runs. I saw pink spots for a few days, lol. The end result of my efforts was a trailer that is like no other when seated inside. There is very little exterior noise (if windows and doors are shut) and it takes quite a bit less heat or A/C to get comfortable. Insulation in trailers rules, the more you can get into the trailer and the precision that you use if using foam board, pays big dividends going forward.

Good luck on the floor, once you dive into it, you will understand what needs to be done.

[isonychia]

budwich wrote:
OP... go from the underside of things. Get a 1 in. forstner bit and drill a "inspection hole" into the bottom "flooring" beit what it is... ie. if its a sandwich, only do about 1/4 in for the lower layer... or otherwise. Do the drill depth slowly. This will give you an opportunity to see if there is wetness or otherwise (ie. continuous load pressure weakening the foam if it is). Then you can decide on further action once you understand what you are up against.

Budwich, thanks.

My plan was to remove the under-belly. It's a hard rigid material held with screws that I assume are secured directly to the steel framing. Or maybe they are secured to the wood joists.

My only apprehension with doing it this way is I'm thinking if there is fiberglass batt insulation, it may fall out of the bays unless they secured them properly when it was built.

iso

[budwich]

OP... go from the underside of things. Get a 1 in. forstner bit and drill a "inspection hole" into the bottom "flooring" beit what it is... ie. if its a sandwich, only do about 1/4 in for the lower layer... or otherwise. Do the drill depth slowly. This will give you an opportunity to see if there is wetness or otherwise (ie. continuous load pressure weakening the foam if it is). Then you can decide on further action once you understand what you are up against.

[isonychia]

westend wrote:

isonychia wrote:

westend wrote:
It sounds like leak prevention has been an afterthought. I'd suggest to do an interior pressurized leak test. That will reveal any structural leaking. You can check plumbing supplies and drains by operating them. Check tightness of plastic drains while you're there.

An afterthought? Not really.

An uneducated rv person, yes.

I assume the pressurized leak test is for the plumbing system?

I have been on the roof a few times and visually inspected all the lap sealant etc. I have never noticed any problems. However, if subtle pinholes can let in that much water, than that is something I cant prevent. In which case people should not bother inspecting all the seams on a TT roof and just keep putting on loads of lap sealant every year.

Everytime I look at these seams it's impossible to tell if there are any pinholes. Between the bumpy texture of the lap sealant and dirt that covers things, pinholes can easily get unnoticed. Even after cleaning the seams it's tough to tell.

The system these companies use to build these things is horrible.
These TT have flat roofs, with a rubber membrane and there are 10 items penetrating the roof, antennae's, vents, AC units, solar panels, ladders etc etc. It's just a combination for a disaster.

To make matters worse, they use luan roof panels, OSB subfloors and wood framing.

I understand it's the nature of things, it's just a little annoying to try and prevent leaks when the system is not designed well.

I take all the precautions I know how. I cant prevent them all if I cant see the problems. I visually inspect the inside of the trailer and always feel the walls and floors for any signs of wetness or softness. Thats how I found out the water heater drain plug flange lets water in from the outside.

If pipes running underneath the subfloor have sprung a small leak and are wetting the subfloor, thats impossible to find. It's hidden.

The AC thing is definitely my fault. After some researching I didn't know they were a major source of water problems. I didn't know I was supposed to tighten the bolts to make sure they have not come loose. (I don't move the trailer, it's static)
I didn't know I need to dismantle it, remove it from the roof and check the seal to see if it needs to be replaced. Now I do.

iso

The pressure test introduces a large volume of air into the interior of the structure (accomplished with various blowers) and a soap solution is sprayed onto the exterior, including the roof. Any pinhole or void will bubble up readily.



I understand your opinions on the membrane roofs. IMO, they aren't a good solution to a transported house. They do require continued maintenance unless......you discover Eternabond tapes. The tapes are time consuming to install because the surface needs to be immacuately clean (think solvent clean) but, after installation, they guarantee a leak-less seam. There are many on this Forum that advocate for Dicor lap sealant, preferring to add some over existing seam sealant. They report no leaks so both systems have adherents.

The AC seal is what it is. If the gasket is observable to be intact and your confience is up, you could try tightening the bolts. I'd opt to remove the bolts, pull the AC and install a new gasket. Age does have her ways.

Getting back to the flooring issue: A composite panel floor made from a sandwich of plywood sheathing and foam is a disaster waiting to happen. The interior plywood sheathing is not rated for floor use so any loosening of the foam to the plywood skin results in a failure of the panel. These composite panels are good for walls and roof applications but fail as floor systems. The repair is to remove interior faced plywood and flooring, exposing the foam (or what remains of it intact), installing a filler that will adhere to the new plywood floor sheathing replacement (typically spray foam). Install new flooring.

If you're blessed with a conventional floor rated floor sheathing attached to floor joists, repair is much easier. Flooring is removed, plywood is examined for failure and replaced as needed. Any damage to floor joists from water leakage or rot can be replaced or ledgered from the interior.

FWIW, after I removed the carpet inside my trailer, I ended up cutting the plywood sheathing out to both repair rot damage in two areas and to install foam board in the empty joist cavities.
The under belly of my trailer is a continuous aluminum skin, it provides excellent water shedding.

If you have an assumed plumbing leak or need to inspect the floor from beneath the trailer, both Coroplast or spun fabric can be removed and reinstalled. A search of the Forum should turn up a lot of hits and tips.

Again, I'd suggest to pressurize the interior to locate any or all leaks. Some guys do it with a leaf blower. I use a conventional furnace blower that I mount on a ladder and blow through a removable sash opening in a vinyl window. If this Forum was more friendly about "stickying" instructions for some of these maintenance procedures, I'd capture the process and submit it. I just got tired of listing the whole process. Maybe a search will find one of those threads.

Good luck on finding the leaks and repairs. You're not alone with this. 😉

Thanks for the info westend.

I already ordered 3 rolls of the tape and a new ac seal. I hope it's the 14x14 one.

To clarify. If my floor is composite, foam sandwiched between 2 sheets of plywood, is that simply sitting on top of the floor joists with the lower layer of plywood fastened to the floor joists?

I think my trailer is simply OSB with regular fiberglass insulation. One of the exterior hatches has a seal problem and water has gotten inside. When I was trying to fix it, (adding thicker foam weather stripping) I pulled back the carpeting and I could see the subfloor was simply OSB with fiberglass insulation underneath. So I assume thats how the rest of the floor is.

I also assume R13 insulation is what I should purchase to replace the existing?

A few more questions.
When I remove the sections of flooring how bad is it if I leave the sections under the refrigerator and kitchen sink if there is deterioration on those panels. Assuming I find the source of the leak and stop it?

There is a wall for the bathroom. I am not sure if I will be able to remove the plywood subfloor from under those wall sill plates. I figured I would cut around it if I need to. Is that ok?

Thanks,
iso