Leaks possibly around skylight

Country · 03-29-2021, 09:45 PM

Hey folks,
Today we found moisture and some mold inside around the bathroom skylight. I'm guessing there is a leak.
Has anyone else had this happen?
2009 189FBR
Thank you.

profdant139 · 03-30-2021, 02:32 PM

I don't know for sure that you have a leak -- it could be condensation, depending on where you are -- but I would recommend a Maxxair Vent Cover. Easy to install, and you can leave the skylight open a little, rain or shine, to improve ventilation.

**LJAZ** · 03-31-2021, 07:29 AM

I have not had this happen, but, if it's the same as mine it's a fixed skylight and doesn't open. You'll need to get up on the roof and inspect the caulking around the skylight. If its cracked or peeling you'll need to get some butyl caulk and reseal it.

profdant139 · 03-31-2021, 10:09 AM

Well, LJAZ, I have just learned something! I did not know that there were RV skylights that did not open.

**LJAZ** · 04-01-2021, 08:37 AM

Yup, and it's strategically placed right over the bathtub. So if you're tall like me you can stand up straight when using the shower.
It is a standard size 2' square though so I suppose you could replace it with a vent that opens. But then I think you'd whack your head on the mechanism that opens/closes it.

Eagle · 04-04-2021, 08:11 AM

The skylight over the bathtub in my unit does not open either nor is it square, but oblong in shape -- about twice as long as wide.

Citycamper · 04-04-2021, 11:50 AM

Take off the decorating molding and you will see that at the factory they just cut a hole through the top of the trailer, installed the skylight over it and put the molding on. Now they weren’t exact in the hole and you will see that they didn’t put any sealant on the ceiling board nor the roof board. Moisture from the shower creeps into these boards and make them start to mold and rot. You might get lucky and be able to cut some of the rot out then coat it with some wood rot stabilize, coat the whole opening around with sealer either a silicon based or similar product. Had the same problem with mine from day one and I fixed it this way. Also check your vent stacks, they did not use hole saws to cut out the stack hole but appear to have gone to work with sawzalls. Had to take the caps off and fill around the pipes with expanding foam then backfill with sealer on mine.

Agnitio · 04-04-2021, 02:27 PM

Do you keep a heater in the trailer as part of the winterization? On my 1st trailer years ago, I learned the hard way this can lead to condensation, and in an unventilated space it can be damaging

NorthPuffin · 04-05-2021, 06:57 AM

FWIW, the skylight over my shower is fixed as well.

I want to muddy the waters a little on the epoxy v. rot discussion. I come at this from the perspective of having grown up with wooden boats and then designing and building fiberglass boats. Penetrating epoxies like Git Rot™ and Wood Rot™ are not as wonderful as their advertisers would have you believe. A better choice is good surface prep and a "structural" epoxy such as West System or even JBWeld. Stay away from the "table top" epoxies, simply because they are more expensive.

Epoxies are thermosetting polymers that come in two parts--a resin and a hardener. When you mix the two components in the correct ratio, a chemical reaction occurs, resulting in a very hard surface with high resistance to water, scratches, solvents, and many chemicals. That resistance is key. The solvents used to create penetrating epoxies leave the product much more porous so the small water molecule can easily penetrate them. Read that again. Penetrating epoxies allow more water to get to your wood than structural epoxies do.

Still, we want to get the epoxy itself to penetrate past the dry rot into solid wood. There are a couple of techniques. I recommend doing both. The first is to simply use extra slow hardener. The longer open time (you want 3-4 hours) allows the epoxy to soak in more. The second technique is to heat the wood before applying the epoxy. Get it a good 30-35°F hotter than ambient temp with a heat lamp or heat gun or hair dryer. As the wood heats up, the air inside the wood cells expands and outgasses. When the wood gets good and warm, turn off the heat source and apply the epoxy. The epoxy viscosity will drop (it will get runnier) as it hits the warm surface; you want that but watch for drips. Then as the wood cools, the cells will pull in the now-warmed epoxy with it.

As an aside, the heat is a balancing act. Heating the epoxy will shorten its open time. The epoxy reaction is exothermic so it heats up all by itself as it cures. Too much external heat or too fast a reaction will thin it too much so it runs out of your wooden part. It can also deform or even melt nearby thermoplastic parts.