Stopping Mold and Leaks in Skoolie Subfloor After Heavy Rain

[underthesun]

Hi all,

My bus has been through two atmospheric rivers recently as I’ve been installing the floor and framing, and I’m encountering a big issue with a leak. Mind you, before this the bus has been sitting out in PNW rain for over a year and not leaked in this spot, so I’m sure it’s something I did that caused it to start, however we have had abnormally more rain recently. I also think how my bus is parked and the way it’s angled has exacerbated the issue with water pooling in one corner, however it’s still an issue that shouldn’t be happening.

when laying down my subfloor (which I’m doing by glueing down a layer of 2” foam core insulation and then advantech osb), I screwed a small strip of another plywood along the back door to act as a cap for the foam so it wasn’t exposed.

Now this piece of wood is completely soaked in both corners and a small spot on the middle, and mold is starting to grow. I’ve done everything I can to figure out where the leak is coming from and it seems it’s coming up from underneath or possibly somewhere where I can’t see because the floor is already installed.

I’m at a complete loss of what to do. Should I try to cut through and remove this whole chunk and then somehow patch it back up?? if so, how? should I replace this rubber gasket (which I’ve pulled out for the photos), or just reseal it with sikaflex? I’m so worried about causing a lasting issue and am terrified of mold growing. and then to fix the leak, should I drill holes in the sill so the water doesn’t collect and instead flows through to the bottom? but then what to do about this moldy piece of wood…

please help! any and all ideas welcomed. i’m desperate and tired

 

[Marceps]

Before attempting any repairs, you need to determine the source of the leak. I doubt it's “coming up from underneath”. Keep looking. Create rain if you have to.

 

[skydawg]

Is it not just coming in from a poor seal at the top/sides of the rear exit door (based on where the water is)? Maybe tape off the external handle to make sure it isn't coming in there.

Is your ceiling exposed or do you still have the stock insulation / sheet metal up? One thing you can do is wait until dark and get out a flashlight to see if you can spot any reflections from dampness.

 

[Bjorkinman]

I would be highly suspect of that door and the seal. When it rains (or you use the water hose up top) go investigate from the inside. After you sort out where the leak is coming from I would dry that spot out by running a dehumidifier in the bus and then cut out any section (use a utility knife, i wouldn't start sawing away) then apply a couple coats of mold resistant primer like Zinsser or Kilz. Also, are you going to prime/paint over the subfloor?

 

[FawnaFox]

Looking at that door seal, it's likely that it's leaking, If it were my bus, I'd look up where you can find a new seal and replace it, doors and windows on these old busses don't all hold up after 30 years. My bus had almost all of the windows leaking from somewhere. In my case it was removing and replacing the caulk. For my emergency exit windows that leaked, I opened them and sprayed flex seal in the gap and closed it. But i assume you want to use your door, like me. So find a new seal and try a leak test.

If it's not the door, check the bottom of the windows during rain (or artificial rain) with a flashlight to see any damp spots. If it's not that, see if your roof is leaking. Usually the emergency exit hatches, especially because they're almost always made of plastic, I just removed mine and replaced them with steel patches.

 

[Mr P]

I'd get some bleach...

 

[Jolly Roger bus 223]

look up mold stat.
it is a commercial/industrial strength mold killer

 

[kidharris]

Hi all,

My bus has been through two atmospheric rivers recently as I’ve been installing the floor and framing, and I’m encountering a big issue with a leak. Mind you, before this the bus has been sitting out in PNW rain for over a year and not leaked in this spot, so I’m sure it’s something I did that caused it to start, however we have had abnormally more rain recently. I also think how my bus is parked and the way it’s angled has exacerbated the issue with water pooling in one corner, however it’s still an issue that shouldn’t be happening.

when laying down my subfloor (which I’m doing by glueing down a layer of 2” foam core insulation and then advantech osb), I screwed a small strip of another plywood along the back door to act as a cap for the foam so it wasn’t exposed.

Now this piece of wood is completely soaked in both corners and a small spot on the middle, and mold is starting to grow. I’ve done everything I can to figure out where the leak is coming from and it seems it’s coming up from underneath or possibly somewhere where I can’t see because the floor is already installed.

I’m at a complete loss of what to do. Should I try to cut through and remove this whole chunk and then somehow patch it back up?? if so, how? should I replace this rubber gasket (which I’ve pulled out for the photos), or just reseal it with sikaflex? I’m so worried about causing a lasting issue and am terrified of mold growing. and then to fix the leak, should I drill holes in the sill so the water doesn’t collect and instead flows through to the bottom? but then what to do about this moldy piece of wood…

please help! any and all ideas welcomed. i’m desperate and tired

I read all of the current replies. I worked as a roofer for over 30 years and have found thousands of leaks, mostly in commercial construction which involves a lot of metal. If you have access to the underside of the structure. Its not that hard. Just remember that water flows downhill and will follow any degree of slope and when metal or any other impervious material is involved it may come out a long way from where it entered because it will go downhill until it finds a hole, screw, lap, or overflows onto a lower panel (caulk or sealant, often put there in a previous repair attempt, can form a dam that will hold some water back until it overflows, very common). Look for streaks left by the leak flow or if you see a pool on the floor, look straight up. Start at the lowest sign of water and trace it up hill.
If using a water hose, start low and slowly go up - dye is useful. Starting at the roof can be confusing and doesn't show you where the leak is, only that you have a leak. High pressure is only useful for simulating a driving rain. Capillory action making water go up hill is rare, but can happen, but in small amounts. It can happen that there is more than 1 leak or that the water is originating in doors, usually condensation or faulty plumbing.