Moisture trapped: shower skylight dead space

[chaps2018]

Checking the roof for debris last week I notice moisture collecting in the area between the exterior clear skylight and the interior translucent ceiling panel in the shower.

Bad thing-didnt even know it was there until going on the roof after a few showers.

Wondering if this moisture from the shower will drip behind the wall.

[chaps2018]

[aceinspp]

I've seen this problem on my last two campers. Don't know what the fix is except let the sun dry them out. Later RJD

[Decon Blue]

There has to be some way Air is leaking between the two. That’s the only way the moisture in the air would form the water droplets. Looks like roof side is sealed so must be inside not sealed properly.

[chaps2018]

Totally agree. I have not disassembled the inside panel yet but it looks like the same type of trim you have in the bath exhaust fan. (ie, not designed to be a moisture barrier)

[Big Bill]

I’d check the vents in the roof , does the moisture disappear after awhile? And yes it will drop down to the side wall also check the seal to the ceiling

[JimV]

Check the skylight for hairline cracks near the screws that fasten it to the roof. I would also take the screws out of the inner skylight to see if they are wet or rusted. If moisture is getting in I would have the skylight replaced.

[Gm Mike]

There was a factory recall for the sky light on my 2013 8289. It had to do with an improper sealant used which caused the skylight material to become brittle and crack. The deal was not to worry unless a problem was observed. In my case I had moisture between the 2 surfaces and had taken the inside apart and dried it out. This was short lived as a leak developed so off to the dealership it went. They replaced the skylight and resealed for free and no more issues.

[up2speed4]

Had it happen to me. I thought it a fluke so I just took down interior portion of the skylight and wiped it dry. Next morning it was back. Now I have to assume the moisture coming from roof. So I check roof caulking and then re-caulk every crack i could find. That fixed it.

[larrytbm]

On mine, the skylight sides are open into the attic. Any humidity in the attic air space will condense on the coldest surface. That will be the underside of the exterior clear panel.

You could look for ways to vent the air space better, maybe a solar powered 12 v fan. Or remove the inner panel and consider insulating around the edges to minimize the amount of air providing moisture.

Finally, while the inner cover is off, add some thin foam tape to the screw flange to reduce moisture from the shower.

[Boss Hoss]

Originally Posted by JimV

Check the skylight for hairline cracks near the screws that fasten it to the roof. I would also take the screws out of the inner skylight to see if they are wet or rusted. If moisture is getting in I would have the skylight replaced.

Which is what I had to do on both of my skylights because they were both cracked.

[crunchman12001]

Originally Posted by Decon Blue

There has to be some way Air is leaking between the two. That’s the only way the moisture in the air would form the water droplets. Looks like roof side is sealed so must be inside not sealed properly.

The interior skylight shroud is not sealed. The interior "glass / plastic" is attached to the shroud trim ring.

[chaps2018]

It appears you are correct. The skylight is open to the attic AND the interior skylight shroud is not sealed.

I will look at the effect of running the exhaust fan while taking showers (not a popular option w/DW & teens). Most likely solution for us might be sealing the interior shroud. Will be interesting to see if moisture comes from the attic.

Will inspect exterior skylight for cracks and attempt to seal interior shroud this weekend and provide an update.

[Cypressloser]

First of all make sure the attic vents are not blocked.
The inner skylight has no seal and any condensation between the inner and outer skylight has to evacuate through the attic vents.
However, I wouldn't hesitate to pull the inner skylight down, apply a layer of soft foam tape (5/16"?) and put it back up, but the air space is still part of the attic and prone to condensation because of the lack of insulation.

P.s.: We have the ceiling vents blocked during the winter months and use a dehumidifier to catch the moisture and keep the warmth inside, works great for us.

[chaps2018]

Attic vents?

[chaps2018]

Re: sealing the interior shroud-- my plan is to use clear sealant (interior skylight lens/shroud surround trim ring interface) Then use foam tape as noted above (perimeter of the shroud trim ring/cieling interface)

[Cypressloser]

Originally Posted by bjlakatos

Attic vents?

Yes, we have 2 on our 43' RiverStone.

[crunchman12001]

Originally Posted by bjlakatos

It appears you are correct. The skylight is open to the attic AND the interior skylight shroud is not sealed.

I will look at the effect of running the exhaust fan while taking showers (not a popular option w/DW & teens). Most likely solution for us might be sealing the interior shroud. Will be interesting to see if moisture comes from the attic.

Will inspect exterior skylight for cracks and attempt to seal interior shroud this weekend and provide an update.

The bathroom exhaust fan should be run during every shower. You must get rid of all the moisture a shower creates. I would not seal the interior shroud, just pull it down and add fiberglass insulation around the skylight to seal off the attic and reinstall shroud. What happens if you seal it and it still fogs over, now you really got a mess with trapped moisture.

[chaps2018]

Update:. I removed the interior shroud. The frosted interior skylight lens was dbl sided taped to the shroud ring. The tape was releasing in spots around the perimeter. I suspect this direct air path from the shower to the attic is the culprit.

As you can see the attic had insulation (albeit one side better than the other). I plan to beef up the insulation a bit.

I will replace the double sided tape on the interior lens and ensure a more air tight seal. I would rather use clear sealant but will yield to the recommendation above while I monitor the moisture for the next few trips.

Also will inspect the exterior skylight for cracks/sealant as recommended above.

Pic looking out the clear external skylight rear side --trailer in storage :-(


Pic of front side with better insulation


Pic of attic side of shroud with the lens separating from the shroud ring


Internal view of the shroud

[larrytbm]

That was my problem as well. Double sided tape doesn't work in high heat climates. I completely removed the clear panel, cleaned the tape off both pieces. Then ran a bead of clear silicone caulk. Used duct tape to hold the panel in place til it set. Then ran a second bead around the edge