Replacing swollen wood on slide out bottom (outside)

[jayspi]

Disclaimer: I'm a complete newb. This is my first RV. I have an issue that I want to try repairing myself, though. Here goes...

Note: The pics are here. The problem I'm concerned with are the ones on the outside bottom of the RV. I already had the dealer dry out and patch the wood on the inside corners (it wasn't rotted, just wet).

I recently bought a used 5th wheel and found that there is debris coming in one of the corners when I bring in and then retract the slide out (see attached pics). From what I can tell, the original problem was caused by water that was coming in the corner of the slide out. I had the dealership re-caulk that and dry the unit out. However, the problem now is that the undercoating in that corner got swollen from the water. Now, when it rains (and I live in the Pacific Northwest so at this time of year it's constantly raining) water runs down the side of the slideout and then runs underneath the underbelly, which is continually making the problem worse.

Now, I *could* take it back to the dealer but they did a pretty half-@#@ job the first time around. I know they won't repair it well since it's a used unit. So I want to fix it myself.

First step is to install a slide out cover, which I'll be doing this week.

Second step is to put some sort of lip on the bottom of that side of the slide out to keep condensation from running under it in the future (I found some good Youtube tutorials on that).

The THIRD step, and the one I have questions about, is how to patch the bottom of the slide out so that it doesn't keep dragging debris in with it.

I contacted the dealership and this is what they suggested: "A suggestion would be to get what’s called belly rap tape that comes in 4 inch width. You can use that to cover the area where the corners are or even go the whole length of the underbelly of the slide just to make sure.. The area would need to be dry in order to do this and the wood sprayed with undercoating. "

So that raises two questions for me. First, what does he mean by "spray the wood with undercoating"? I did some research and can't find anything that relates to that.

Second, after I've put on said undercoating, what type of belly wrap tape do you guys recommend? Searching around on Amazon leads me to the "Flex Mend Underbelly Repair Tapee", but I have no idea if that's what I need or not. It seems to be more for repairing the underbelly of a unit, not for patching wood.

Thanks in advance for any tips!

[jayspi]

So this is an old thread, but several people had wanted to know the outcome. I was on RV.net for some other stuff today and realized that I had never posted a follow-up. Thanks to all of you who helped with the other 2 issues I had, by the way.

I got the rot doctor and all of that, and was ready to start following their instructions and injecting it into the wood. As I got further into it I realized that the rot went deeper then I initially realized. It had started to rot the beam that was directly under the slide, parallel to the one I had been working on. I couldn't see that until I cut more of the flooring away.

That concerned me since that beam was offering support to the slide. I admitted to myself that I was in over my head and took it to the dealer. After talking to a couple of managers they cut us a really good deal and did the work at cost. Their service manager, who we ended up becoming friends with over the last few months, felt pretty bad that they had sold the unit to us in that condition. The whole service department bent over backwards to fix that and some other issues, to the point where they covered over $600 in labor to replace one of our tanks.

Anyway, they were able to save us some money by not removing the slide altogether, but they did have to raise it about 4 inches and put shims along both the studs that were rotted. It went back under the bunkroom and slide so it took them a couple of days.

At the end of the day it cost us $1100 to fix all of that and the rot under our door.

My wife and I do truly feel that the dealer treated us right and that we couldn't have repaired this on our own, but we also learned our lesson: NEVER buy an RV if it has ANY odor in it at all!!! We had persuaded ourselves that the musty odor we smelled was just because it hadn't been used in a while, but that obviously wasn't the case.

[BurbMan]

Yes that is definitely do-able. Once the floor is dry, get some of the Rot Doctor CPES as mentioned above. Saturate the end grain of the OSB to seal it up, then you can sand or plane down the bottom to reduce the thickness of the OSB and keep it from dragging. The Rot Doctor CPES is actually an penetrating epoxy so it will restore strength to the OSB, plus since you had wood installed over top of that it should be plenty strong.

Once the OSB is the proper thickness, you can actually paint that CPES on the bottom of the OSB to seal it up. With a drip edge installed, that should fix your problems. I would paint the whole underside of the floor and the other edge as well if you have any questions about whether it might be in for the same damage.

You are significantly ahead of where I am....the factory installed a sheet of Reflectix (think mylar-coated bubble wrap) under the carpet instead of padding to help with insulation. That Reflectix sheet kept the water from soaking into the carpet, so I never knew it was leaking. Meanwhile the Reflectix also didn't let the wood breathe, so that's black mold that you see in the picture...a real mess and why I am replacing the whole floor.

[jayspi]

Thanks for the pics Burbman, we're definitely dealing with the same issue.

By the way, I want to say thanks to everyone again for all your help. My wife and I decided to go full-time a few months ago and we've discovered the RV community is incredibly friendly and helpful. We've made quite a few friends already and we're not even on the road yet!

Regarding the band-aid vs repair issue, I understand what everyone is saying about the BEST repair being to replace the OSB. However, I have to be realistic about what our options are right now. The main issue, even more than the weather, is space. That kind of space just doesn't exist in the Seattle area unless you own a house. If I wanted to do something like that then my only option would be to rent a garage (a large one) and that would probably cost more than just paying a service center to do it. I am leaning more and more towards replacing the OSB in the summer time though.

On the other hand, I've decided that I do need to do more than just put a liner over it to keep it from getting wet in the future. As you guys have pointed out, it's very swollen and it needs to have the loose wood shaved off. Otherwise I think I'll just tear loose any aluminum siding that I put on, or, even worse, cause damage to the seals when the slide out comes in an out.

I was just talking to my wife about it and we came up with an idea. We're going to go ahead and put the slide out cover on it and then tent it to hold in heat. We'll put a couple of space heaters under it, as you guys have suggested.

Once it's dry (and REALLY dry) I can do a better repair. I think that scraping back the swollen wood, putting an undercoating on it, putting the aluminum flashing on it to prevent further scraping, etc, and then putting a drip lip on the edge would be a good fix (again, considering that replacing the floor isn't an option right now).

Two questions:

1. What would you guys recommend for undercoating?
2. Would it be a good idea to do this one BOTH sides of the slide out, even though the other side isn't showing this same problem (yet)?

Finally, one or two of you pointed out that the structural integrity of the slide out could be a concern. After looking into it more I'm pretty sure that there are two separate issues. I think that the water on the corner of the slide out was coming down the wall. However, that looks like it was sealed even before the dealer "repaired" it for us. It was stained from water but not rotten or even soft. I pressed into it with a screw driver and it was as solid as the rest of the flooring. That's why I don't think I have rot in the walls, and I think the structural integrity of the slide out is "fine" (if "fine" means acceptable and useable). The studs in the corners had to have gotten wet but I don't think they rotted.

The OSB is also not rotten, just swollen and literally coming apart every time the slide out is retracted.

The area that is rotted is where water came in under the slide from the problem that I'm looking at now. That's on the main floor in one corner, where that edge of the slide out sat when it was retracted. I can tell that water came in when the previous owner brought the slide in and then it just sat there with the water soaking into the carpet. There's some mild rot on the main floor of the living area (not the slide out) in one corner from that. I looked at it from underneath and the stud isn't rotten. We don't walk on that area so I'm holding off on replacing that section of flooring until more critical things are done.

Overall, I feel like the unit is in good condition except for this and the rot under the door frame.

[BurbMan]

I am in the process of fixing the same issue...I have some pics but have not had time to write up a post yet. You have identified the issue, there needs to be a drip edge along that outside seam to keep the water from creeping into the floor. Mine was built just like yours, OSB with a hard surface applied to it.

I have the floor out of my slide now and am replacing with 2 pieces of 1/2" plywood laminated together with Titebond III waterproof wood glue. I applied 4 coats of Spar Varnish to the bottom and edges. The bottom needs to be a somewhat smooth and slick surface because as the slide comes in, it rides on 5 nylon blocks installed at the edge of the main floor.

The problem with the OSB is that once it swells you are done. If you want to try and fix it, first thing is it needs to DRY. Tarp the slide out and use a hair dryer. Get some of the rot doctor and the injection kit and shoot it in the OSB floor. Once it dries/hardens, then you can trim the floor back to the original thickness and I would coat the bottom with several coats of spar varnish.

For the drip edge I got some plastic J-channel for drywall, and cut it down:





Tarp setup:



My issue:



Here's the edge:



The factory coated the edge of teh OSB with what looks like Plasti-Dip or Flex-Seal, and it cracked over time...as the water got in due to lack of a drip edge, it swelled the OSB, opening the cracks more, allowing it to absorb more water, which swelled it more, etc etc.

[Denny___Jami]

Looking at your photos I can tell that the OSB flooring is beyond saving and is falling apart. So you can bandaid it or replace the floor, the manufacturer used the cheapest OSB board available so it was a problem waiting to happen. If you replace it and use OSB go to a lumber yard not a big box store and buy some high quality OSB sheeting or plywood, you may have to laminate 2 pieces together to get the right thickness. Cover the underside with fabric that higher end units use to keep the wood dry and use aluminum flashing to seal the edges. You may want to go to a dealer and look at how other manufactures seal theirs.

Denny

[westend]

I would flash the edge of the OSB, scrape the loose stuff off the face and spray the exposed OSB with undercoating spray in a can. I'm guessing time of process to be around an hour.

If you need to dry out the slide, how about tenting it with plastic and putting a heater under there. If the heater doesn't have enough airflow, add a fan.

[jayspi]

Thanks for the info, NMDriver. What I'm experiencing does seem to be pretty common problem to slide outs. It's a shame that the previous owners didn't maintain it. I don't know why you'd spend money on a new RV and then let water poor in. They had to have seen it on the carpet when they moved the slide in and out.

The weather is supposed to hold through tomorrow so I've made a plan of action:

1) Put the slide out cover on. I do feel like the dealer caulked it properly (it poured rain for 3 days straight with no signs of leaking) but with the slide out cover I don't have to risk more leaking up there. I'll still re-caulk it myself later since it'll get damp no matter what I do.

2) Put the PVC shower lining above the rim of the slide out, as suggested, to keep water droplets on the side from running underneath the bottom of the slide out.

3) If time permits (unfortunately I have to work tomorrow) I'll put the aluminum flashing and caulk on it. My concern with that, is that I may have to trim down some of the wood on the bottom to keep it from scraping as it comes in, since the wood has swelled with moisture. The weather is supposed to be clear again over the weekend (knock on wood) so I may tackle that portion then.

The good news is that we've been renovating it from about 2 weeks and the only damage we've found is this area and some rot under the door. At the door, the sealing on the outside top of the frame had come loose and water had run down the inside of the door jam. The wood is completely rotted to the point you can dig it out with your finger. However, it looks easier to fix. The water ran straight down the inside of the door frame and into the floor, then out the underbelly. It doesn't appear to have caused damage to anything other than that tiny patch. It's also not supporting any weight, since the metal of the door frame is over the piece that's rotted. We wouldn't have even known about it if we hadn't pulled up the vinyl to put our own flooring down. There's no way I can dry that before summer without putting it in a garage, but it'll be OK until then as long as we don't jump up and down on it.

Other than that, we've been over it with a fine tooth comb and haven't found any other issues. If we can get these two things fixed--and I'm sure we can--then I think we'll have a pretty solid rig.

geotex1 - regarding taking it back to the manufacturer, that's a really good idea. If I get in over my head then it's good to know that it's an option.

[geotex1]

Good luck with your band-aids - totally understand considering the weather. Further, and worth exploring for yourself, it that the manufacturer will build you and entire new slide out box ready to install if you are will to pay for it. I say this since you also know there's damage in the wall. Keep in mind that is composite construction, and the strength comes from having a solid, intact sandwich. Since you got a 5er, a trip out to the factory for a pre-arranged repair could be very realistic...

[NMDriver]

I had the same issue in the same locations. I know it will be hard to get the unit dry up there, compared to here in NM, but that is the most important first step.

My leak was the slide seams on the ends leaking and on the roof seam from front to rear. I used an epoxy penetrating wood restorer on one end of the slide to restore the wood to a hard durable condition. I cut out the rot on the other end since it extended about 1 ft into the wood. The epoxy restorer worked fine but I think the total removal was a better fix. Just not as aesthetically pleasing. Anyway, I was left with a 1/4 inch raised floor on the front end of the slide due to the overlap to secure the patch. You have to keep the bottom at the same level, obviously, so be careful not to have any screws, etc. extend past the prior level bottom.

I used Henry's EPDM paint, primer, and fabric tape to fix all the seams. That stopped the water intrusion. I Wrapped the EPDM fabric and paint around the bottom of the slide and made a small drip ridge on the bottom edge. All I did was pinch the fabric tape up and paint it with the EPDM. I sealed every seam horizontal and vertical even if I did not think it was the current cause of the leak. A gallon of paint and primer goes a long ways so you might as well redo the whole slide roof while you are at it. Do not forget the seam where the rubber gasket attaches to the slide.

Hope this helps and it may sound tedious but it is just one step at a time.

[jayspi]

puttd wrote:
I'd say that if you are in the position to make the dealer take it back, do that. If you are in the position to make them actually fix it, do that.

I couldn't get them to take it back since we've done a lot of renovation on it. I could probably get them to REPAIR it, but I really doubt they would actually FIX it. In their minds it's two separate things. If it's something that I can fix myself then I'll know it's done right...

HappyKayakers wrote:
Here's a company in the Pacific northwest that should understand your problem. I've used the epoxy sealer and it does a great job. http://www.rotdoctor.com/products/cpes.html

Thanks! I'll check them out.

geotex1 wrote:
When you talk about debris being drug in, I'm envisioning you're getting fragments of that OSB that is clearly water damaged and long-deteriorated underbelly fabric. I guess my issue is that you obviously are still getting water in there as evidenced on the, ummmm, "dealer repair." I'm a guy that likes to do a proper repair once over band-aiding it unless absolutely necessary. Big part of your problem on that corner is that the OSB has expanded it making it "fatter" than it was supposed to be to clear as it comes in...

I think you hit the nail on the head. In my OP, your tip about the flexible PVC shower lining was what I was thinking of. I couldn't remember what it was called. I'm going to do that tomorrow while it's still dry.

The debris coming in is what I want to clean up. It seems to me like the board needs to be completely dry to repair it properly (unless I just replace it, but I can't do that either in the rain). I'm finding out that it's pretty much impossible to truly dry something during winter in the Seattle area, so slapping a band-aid on it is the immediate goal.

I'll look into the other tips you suggested. It sounds like that is a good option.

Dr Quick wrote:
From the looks of your pictures, it looks like the leaks have been happening for some time due to discoloration...Also I would recommend that edge of new floor board be weather protected with some sort of Alum flashing. Also if leaks originate higher up, there could be wall damage too...

I have seen a Video on how to replace the floor in a slide, and it was quite a project, as it required bracing slide to the ground, so that wood floor panel could be replaced.

You're absolutely right. There is damage inside the wall. When you tap on it you can tell that the insulation is soft as compared to other sections of the slide out wall. The good news is that the flooring in that corner was not rotted or even soft, which makes me think the wall probably isn't either. On the other hand, there is mild rot where the slide out is dragging water in. I opened up some of the underbelly and looked underneath and it didn't look bad. This summer I think I'll replace the flooring on top of that section, but it doesn't look like the studs need to be replaced.

I saw the same video that you did (or one like it) about replacing the wood floor panel on the slide. To me it looked like a two-person operation, or one person with some good equipment to brace it.

When it comes to repair vs band-aid vs replace, this is a "learning" RV that my wife and I bought. We're going on the road full time and everything we read said to not buy an expensive rig when you're a beginner. We got this cheap and if we want to we can probably sell it next year for close to what we paid for it. That makes me hesitant to spend a lot of money on repairs. If we decide to keep it for a while then I'll invest in making good repairs. If we don't then we'll trade it in. (I doubt I'd sell it to a private seller with this damage...if I did then I'd fully disclose it).

Thanks to everyone for the tips. You guys came up with some great options. I'll do some more research and try one (or more) of them before the weather gets bad again.

[Johno02]

That "Flex Mend stuff looks like pretty good stuff! If you can find what is causing the water to get under there and fix that, the stuff may be the way to go. Looks like I may have to do some of the same type thing, but at least I do have the water source problem resolved. (so far).

[Dr_Quick]

From the looks of your pictures, it looks like the leaks have been happening for some time due to discoloration. My guess is that the OSB board it not water proof, and it has swelled up, as can be seen for what looks like "gaps" in the edge of the board. Board has swelled leaving a rough surface and caused the under liner to tear up.
My main concern would be to find and stop leaks before preceding with repair. I would say that floor board panel should be replaced with a waterproof board and a new under liner. Also I would recommend that edge of new floor board be weather protected with some sort of Alum flashing. Also if leaks originate higher up, there could be wall damage too.
I have seen a Video on how to replace the floor in a slide, and it was quite a project, as it required bracing slide to the ground, so that wood floor panel could be replaced.

I have done leak repairs on three trailers and in all cases once I started, I always had more damage to fix that was seen on the surface. Had to replace wall paneling and even studs and floor joist. Even an entire roof.

[geotex1]

When you talk about debris being drug in, I'm envisioning you're getting fragments of that OSB that is clearly water damaged and long-deteriorated underbelly fabric. I guess my issue is that you obviously are still getting water in there as evidenced on the, ummmm, "dealer repair." I'm a guy that likes to do a proper repair once over band-aiding it unless absolutely necessary. Big part of your problem on that corner is that the OSB has expanded it making it "fatter" than it was supposed to be to clear as it comes in. The end of the OSB is also exposed, and that's not how that usually is. The thing about underbelly tape is that it is designed to stick to the fabric and not really wood so you'll likely peel it right off first retraction! I think if I had to band-aid it, I'd bend up some aluminum flashing that I could cover the exposed end of the OSB and span over the torn underbelly fabric This would also give me a good line to caulk to seal too. Just strikes me that slide-out may have seen repair even before the dealer did what they did. I would also suggest you get some flexible PVC shower liner (Home Depot or Lowes) or some very flexible, thin splash guards material from your local autoparts store. At the bottom of the slide seal at the trailer wall at either end, make yourself a deflector to keep water from "rolling under" if that makes sense.

[HappyKayakers]

Here's a company in the Pacific northwest that should understand your problem. I've used the epoxy sealer and it does a great job. http://www.rotdoctor.com/products/cpes.html