Source of dry rot in floor of 21 foot BF

[robbiny]

Bought a used 2009 25B21FB trailer. Looks great, clean/dry. We've had it about 6 months and keep it inside most of the time. We've not actually used the trailer yet, so haven't run the systems for any length of time.

We just found a soft spot in the floor right next to the dinette and dug out a hunk of dry rot.

Looking for suggestions on where the water might have come from. Looks like the problem may have been fixed, as the wood isn't damp. To see if there's a leak in the water system we turned on the demand pump and didn't run any water. Once the pump built up pressure, it hasn't run again, so we figure there isn't a leak in the water system.

However, given that the rot is in the center of the floor, it's hard to picture how this would have been caused by the roof, which looks good.

Given the location and the apparent lack of any water lines nearby, we can't figure out what might have caused this.

Ideas?

[Jack L]

Have you looked underneath the trailer for the source of the trouble ? I cant see how this could have happened from above without damaging more of the surrounding area. Is there any damage underneath the trailer ?

[Darral T.]

With the current price of BF trailers, I am literally shocked to see this!

[robbiny]

Yes, the list price on the trailer was impressive, which is why we buy used now. The good news is that the factory answered my mail asking for info about this within a half hour. The bad news is that they too were shocked, and don't have blueprints you can use to try to tear the thing apart with minimal damage. They said we need to take apart the dinette to track down the source, which could be the water pump, the fill spout, or the lines heading from the front tank to the bathroom.

The floor is dry, but upon further thought, we've not used the trailer and it may be as much as a year since anyone has. Sounds like we'll be digging in.

[Darral T.]

Just from my experience....I would DEFINITELY leave the damaged spot untouched and start running water through the BF. I guarantee you it will show up in short order....hopefully near where the damage is. It's hard to know whether this is preferable (the wood floor, rot, then a catch...or a total fiberglass hull that would NOT rot...but yet go undetected until mold sets in). Bottom line? ANY leak is bad!

Keep us posted if you will as I'm very interested in the "source" of the problem! Hopefully, the rot is concentrated to THAT area only.

Originally Posted by robbiny

Yes, the list price on the trailer was impressive, which is why we buy used now. The good news is that the factory answered my mail asking for info about this within a half hour. The bad news is that they too were shocked, and don't have blueprints you can use to try to tear the thing apart with minimal damage. They said we need to take apart the dinette to track down the source, which could be the water pump, the fill spout, or the lines heading from the front tank to the bathroom.

The floor is dry, but upon further thought, we've not used the trailer and it may be as much as a year since anyone has. Sounds like we'll be digging in.

[Jack L]

This is so much a puzzle. Once moisture gets into wood, it usually stays. Considering the underside of the floor is fiberglass, I would think it would never dry.


Sometimes you can determine the extent of damage by tapping on the floor. You will hear a much different sound between solid and rotten wood.

[robbiny]

We'll run some tests this weekend and I'll let you know what we find. We (that would be my husband, :-) ) dug out a bunch of the rot, as shown in the photos. But I've discovered more under the dinette, as the wood is soft there just as it was in the main floor area.

Why would you not dig out dry rot?

[tractors1]

If you're not dealing with a structural issue you can buy a wood consolidator product at Loews/Home Depot, etc. Commonly used to solidify weak/old wood in houses - similar to an epoxy, but thin enough to pour or brush. Used a gallon or so of it when resurrecting my 1902 house. Just ask at the paint dept.

[RogerDat]

I would run water through stuff, one item at a time the leak might be on the downstream side of a valve. Also consider normal storage orientation and any seams in the wood.


Lot of times water moves a fair piece following some tortured path of seams and edges designed to lose pursuit (or so it seems).


If looking for a through the hull leak I'm a big fan of divide an area in half and apply water to one half. When you find the half that leaks divide that in half and repeat. Eventually the half gets small enough that you go "oh right there". Or at least know your tearing apart the right place.

[Bob Miller]

Originally Posted by robbiny

We'll run some tests this weekend and I'll let you know what we find. We (that would be my husband, :-) ) dug out a bunch of the rot, as shown in the photos. But I've discovered more under the dinette, as the wood is soft there just as it was in the main floor area.

Why would you not dig out dry rot?

If you just turn on the water pump you can sit and listen for the pump to cycle. Basically it should not ever cycle unless there is a leak. You can turn the pump off overnight and it should still hold enough pressure to not cycle the next morning unless there is a leak.

The more probable cause for a leak may have happened if they hooked up to a shore faucet without using a pressure regulator, in which case you may need to do the same thing, first with the regulator in place and then without.

And, if you do or don't find a leak, I'd still cut out all the dry rot you can get to and splice in fresh wood.

[Darral T.]

I think maybe the question at the end of your post here was directed at my statement saying "I DEFINITELY wouldnt touch it..." (or close). MEANING--- until you find the source of the leak! My hopes would be that when I start running water that hopefully it would fill the cavity that you dug out. I certainly would hate to have new wood in there and do the test and have it soaked...if that makes sense.

Find the leak and stop it THEN replace the wood. No way would I leave any hint of rotted wood in my RV. Sorry if you thought I meant that.

Originally Posted by robbiny

We'll run some tests this weekend and I'll let you know what we find. We (that would be my husband, :-) ) dug out a bunch of the rot, as shown in the photos. But I've discovered more under the dinette, as the wood is soft there just as it was in the main floor area.

Why would you not dig out dry rot?