Living in my 26ft coachmen for the past 6 months now. Im in Myrtle beach.Just noticed water droplets on membrane between ceiling and skylight bubble.its colder here and running electric heat past several weeks.Noticed it last week too and little plastic membrane that is sticky tapped to ceiling besel was unattached on one side. ( Possibly shower steam made sticky tape non sticky)I pulled besel down and whole bubble was wet with large droplets. roof membrane folded over so drops were collecting in ceiling collar. No damage except small edge of luan damp.Upon removal I see the back roof truss is open and I can see back wall of camper. Slight dew on nails and wall membrane on back wall.I would think the heat from in the camper it getting through they membrane and interacting with the cold air in the bubble skylight and condensating..Im thinking to insulate all gaps and openings around roof trusses with collar removed. Then put that membrane back but seal it to the collar with silicone.Is that my best bet?I could of course leave the membrane off too. as this is how I have it now so I can watch it a few days until I get some insulation.Possibly spray foam may be better but I probably will just get a bag of the soft stuff.So is my plan feasible? Anyone have this issue?

donn0128 wrote:Lower the humidity inside.Unfortunately thats not a good answer..Thanks anyway.I don't have condensation issues anywhere else.

“No damage except small edge of luan damp.”You hope but I don’t think so. Time for a complete inspection, repair and sealing. As Don said, lower the humidity.

sounds like you need more insulation in the attic

Sounds like the skylight is not sealed. You are getting moisture from inside the rig to between panels of skylight.Not sure what your installation is like and how to reseal. There is no where for the moisture to escape to the outside, so it stays. If this is in bath, you need to get a better exhaust fan so moisture does get into skylight. Fantastic fan Do you have covers and leave your vents open? If not get covers and leave the vents open at least a couple of inches at all times.

skylight condensation | Good Sam Community

lawrosa
Explorer
Dec 09, 2018
ill try sealing it like I stated. I was thinking on one of these.But I am alone and using electric heater only.
mobeewan
Explorer
Dec 09, 2018
If everything is sealed properly and you have no leaks then there should be no moisture between the skylight bubble and the interior skylight bezel.

I found water was dripping from my bezel flange and that there was moisture between the bezel and the bubble. When I removed the bezel I found the skylight wood framing had damp spots and water had been weeping under the ceiling panels. Upon further examination I wound up putting my thumb through a water damaged spot in the ceiling paneling. The ceiling insulation was wet and trusses had damp and water stained wood. The skylight bubble was cracking around the inside perimeter of the flange and water was leaking through the cracks, running down and wicking onto the top side of the ceiling paneling and spreading out wetting the insulation and rafters. The skylight bubbles eventually suffer the toll of UV damage just like the plastic vent fan hatches and need to be replaced eventually. If your skylight is not cracking and leaking through your caulking on and around the flange may need to be replaced.
lawrosa
Explorer
Dec 09, 2018
mobeewan wrote:
If everything is sealed properly and you have no leaks then there should be no moisture between the skylight bubble and the interior skylight bezel.

I found water was dripping from my bezel flange and that there was moisture between the bezel and the bubble. When I removed the bezel I found the skylight wood framing had damp spots and water had been weeping under the ceiling panels. Upon further examination I wound up putting my thumb through a water damaged spot in the ceiling paneling. The ceiling insulation was wet and trusses had damp and water stained wood. The skylight bubble was cracking around the inside perimeter of the flange and water was leaking through the cracks, running down and wicking onto the top side of the ceiling paneling and spreading out wetting the insulation and rafters. The skylight bubbles eventually suffer the toll of UV damage just like the plastic vent fan hatches and need to be replaced eventually. If your skylight is not cracking and leaking through your caulking on and around the flange may need to be replaced.

Its a brand new camper. There is no damage to the skylight. And no caulking is leaking. The underside of bubble is condensating and running down to the edges..

Amazing that no one had/has this issue.. Maybe no one winter camps.
Huntindog
Explorer
Dec 09, 2018
You MUST lower the humidity inside. Water on windows, skylights etc. is a warning sign. The same thing is happening inside your walls, just slower because of the insulation. If this is a filon walled TT or similar, delamination will be the result if you do not address the issue.... And just worrying about the skylight is NOT gonna fix the underlying issue.

If you have your TTs manual.... Read what it has to say about this.

You are on your way to ruining your TT at present....

And yes, many of us here have dealt with condensation in cold weather.

I use a 40 pint dehumidifier, or leave my vents and windows cracked, depending on how cold it is.
westend
Explorer
Dec 09, 2018
DEfinitely insulate the void in the ceiling. You can probably get some thin batt insulation at a big box store. That can be pushed into the void with sticks or wire. If you source 3 1/2 batt insulation, that can be divided into thinner pieces. Wear gloves.

Basically, you have a condensation point at the skylight. It is an indication of the humidity being too high. Venting is the best solution. You can also insulate underneath the sky light but you'll lose light and the insulation must be sealed totally. Otherwise, you'll have condensation again on the inside of the skylight. You could choose to seal the skylight opening with a transparent material like acrylic. Again, sealing all areas is necessary to eliminate condensation on the skylight.
ktjensen
Explorer
Dec 09, 2018
there are foam insert things you can place up there. You need to insulate anything that shows condensation so there is less temperature change difference.
Lynnmor
Explorer
Dec 09, 2018
lawrosa wrote:
ill try sealing it like I stated. I was thinking on one of these.But I am alone and using electric heater only.

I would think that you would need at least 10 of these units to do the job. Get a real dehumidifier.
GrandpaKip
Explorer II
Dec 09, 2018
The first time we stayed in cold, wet weather, there was a lot of condensation, especially on the windows. Cracking the roof vent and a window took care of it. Easy and cost nothing.
I used one of those little dehumidifiers in the pass through when I had a cargo door leak. It worked in there, but would have had hardly any effect in the main cabin.
ktmrfs
Explorer II
Dec 09, 2018
lawrosa wrote:
ill try sealing it like I stated. I was thinking on one of these.But I am alone and using electric heater only.

pretty much useless. they will pull cups of water/day at best. you need something that will pull gallons/day, a compressor driven dehumidfier. even 1 person will perspire more than what the posted device will handle
ktmrfs
Explorer II
Dec 09, 2018
lawrosa wrote:
mobeewan wrote:
If everything is sealed properly and you have no leaks then there should be no moisture between the skylight bubble and the interior skylight bezel.

I found water was dripping from my bezel flange and that there was moisture between the bezel and the bubble. When I removed the bezel I found the skylight wood framing had damp spots and water had been weeping under the ceiling panels. Upon further examination I wound up putting my thumb through a water damaged spot in the ceiling paneling. The ceiling insulation was wet and trusses had damp and water stained wood. The skylight bubble was cracking around the inside perimeter of the flange and water was leaking through the cracks, running down and wicking onto the top side of the ceiling paneling and spreading out wetting the insulation and rafters. The skylight bubbles eventually suffer the toll of UV damage just like the plastic vent fan hatches and need to be replaced eventually. If your skylight is not cracking and leaking through your caulking on and around the flange may need to be replaced.

Its a brand new camper. There is no damage to the skylight. And no caulking is leaking. The underside of bubble is condensating and running down to the edges..

Amazing that no one had/has this issue.. Maybe no one winter camps.

we camp often on the oregon coast in the winter. outside humidity near 100% day round. If we didn't run a compressor driven dehumidifier we would have your problem. w/o it windows are wet in the morning etc. With it we pull 2-5 gallons of water out of the trailer each day. On occasions even more if we are out and about and come back with wet or damp clothing.

AND when we shower or have the cooktop or oven on the vent fans are on HIGH along with a cracked open window. need to get the moisture from a shower or oven/stove OUT of the trailer! burning propane you get almost 1 gallon of water vapor for each gallon of propane burned. For the furnace and HWH, not an issue, the exhaust gets vented outside. for the stove/cooktop it can be an issue since the exhaust is vented inside. Can be even worse if you are in a humid environment and run a unvented propane heater inside the trailer.