Bathroom Skylight, condensation or leak?

[budwich]

Recently bought a 2007 Terry Dakota. Overall its in good shape. Was taking out the cupboard and bunk in the rear section (trailer is configured with washroom on one side and bedroom with over head bunk and cabinet on the other side).

Notice when removing screws holding the cabinet into the roof that they were rusted and along with some of their heads. Those closest to the bath were the worst while those at the other end of the cabinet were OK.

I climbed on the roof and checked the skylight and vent stack and both appear to be well caulked (looks like dicor stuff). Checked for cracks and such... none. Will try doing a hose test to further confirm (once the weather warms here... still freezing at nights... :-(( ). Went in the washroom and removed the inner "baffle" / plastic diffusion pane. The screws on most of these were also rusted although the painted heads were fine. Once removed, I could easy see that the opening and exposed "sandwich" of board/foam had some markings of water streaks.

I guess one question I have is, should there have been some sort of "membrane" / seal around the opening to elimate exposure of the "sandwich" to moisture condensation in the skylight. Do people with bathroom skylight experience that much condensation build up during a "normal shower" that it would run down the outer doom shell and inner diffuser and / or leak into the "sandwich". The inner diffuser has no gasket / seal. Should there be one? Would that help to eliminate any condensation buildup in there.

Not sure what the next step would be other than "hose test" on the outside along with a reseal and "cross our fingers".

Any guidance on this for a new RV'er would be appreciated.... when our tent leaked, we just had to "grin and bear" it and patch with tent sealant... probably not a good thing here... 🙂

[poppin_fresh]

I had/noticed the exact same issue in my '05. Saw some staining from the inside and thought the outside was leaking. When I removed the inner panel I found rusty screws and staining exactly like what you have. Like you I could not find a leak after hosing or a hard rain.

I determined that when taking a hot shower, steam must travel up and past the inner panel (since there is no gasket) and condense on the skylight lens. It then gets trapped there and was causing the staining and a some damage to the wood along its edges, but fortunately it's minimal. The softness extends maybe 1/4" in from the edges.

Based on this, I applied a thin film of tub and tile caulking along the edges of the wood to help repel some moisture and seal them. I wasn't too worried about the foam as it wont absorb water.

When I posted about this problem, another member was quick to point out that I had nearly a 10 year old trailer, with this very small amount of moisture issue. Because it was such a small problem, it would take another decade or two before this was really a problem. By then surely something else would be a MUCH bigger deal.

Jon

[budwich]

Warmer weather has finally shown up here... 🙂
Its allowed me to get some dicor down around the fan and skylight. A leak may have been coming from the around the fan as it had a "max flow topper" on it which may have prevented the previous owner from readily inspecting the caulk around the actually fan. Hopefully I have attacked it enough with dicor (after removing max flo, cleaning, etc...).

My new question is associated with the damage to the existing roof structure.
There is a small area between the sky light and the side edge of the roof that has bubbled / let go.... area is about 6 inches wide by about 1.5 feet long. It is basically contained the skylight and the trailer side edging.

Is there an easy and successful way of injecting some form of gluing to "re-stick" the area? Is it worthwhile doing anything or will it make things worse? If it stays dry from now on, will it remain and not "grow" any further?

Thanks again for any further guidance and advice.

[budwich]

Well, I tried some spray sealant (by rustoleum). Probably not the best way, as the sealant doesn't "play nice" with the foam core, shrinks / melts it a bit. Not wanting to take it further in terms of coverage so I don't know if its really sealed that well. Probably a better method would have been to use eternabond or equivalent to line the surface.

[budwich]

Aluminum Siding wrote:
As long as the wood isn't weak and rotten you'll be fine. Also if you had the slightest leak the roof would have swollen. Just make it doesn't leak moving forward. I think your fine. My TT is 1 year old. Never a leak and un-painted metal such as screws in the rest room are starting to show rust. The roof screws that hold the shower curton (sp) were not painted and those show rust too.

It is not just the exposed heads of unpainted screws, it is also the imbedded thread portions, as the moisture has moved thru the foam. That's what leads me to believe a significant degree of humidity / condensate is moving thru the exposed sandwich sections.

We have had a couple of days of bad weather here and still don't feel any external water but as soon as its warm enough, I will re-"dicor" the outside and perhaps try eternabond the inside in some form.

[budwich]

Did about 30 minutes of "hosing" yesterday just before an evening rain storm. No water or dampness in the area around the skylight bubble.

Looking at the corresponding opening for the power air vent versus the skylight, the exposed foam core on the power air vent is white as snow while most of the skylight foam core is less so and then the area on one side is severely discolored / stained.

[Aluminum_Siding]

As long as the wood isn't weak and rotten you'll be fine. Also if you had the slightest leak the roof would have swollen. Just make it doesn't leak moving forward. I think your fine. My TT is 1 year old. Never a leak and un-painted metal such as screws in the rest room are starting to show rust. The roof screws that hold the shower curton (sp) were not painted and those show rust too.

[pugslyyy]

I would probably pull it off and check it. I like to use butyl tape underneath and eternabond on top.

If you don't check it, and it is a problem it is only going to turn into a much larger problem.

[budwich]

dabush wrote:
Skylights are leak magnets.

I just completed repair on mine...noticed a bit of water damage on the inside around the sky light...went up and discovered a soft patch around the sky light...pulled back the rubber...3 weekends, 4 roof trusses, 6 feet of OSB board, and a new EDPM rubber membrane later, I didn't put that skylight back in. Instead of a shower skylight, I now have a 12 volt light on the new ceiling.

I somewhat figure that perhaps just based on "house experience" but I don't see any ceiling damage / staining, hence my thinking that perhaps "shower humdity" is the culprit. Having had the trailer for only one week and never owning one before, I am not sure that there isn't a humidity problem for "unprotected"/non-sealed surfaces or where condensation can collect significantly (ie. top bubble) and then run down to the lower unprotected "sandwich".... but its certainly just guess.

[budwich]

wmoses wrote:
Pictures?

I'll try as soon as I can figure out how to post it... 🙂

[dabush]

Skylights are leak magnets.

I just completed repair on mine...noticed a bit of water damage on the inside around the sky light...went up and discovered a soft patch around the sky light...pulled back the rubber...3 weekends, 4 roof trusses, 6 feet of OSB board, and a new EDPM rubber membrane later, I didn't put that skylight back in. Instead of a shower skylight, I now have a 12 volt light on the new ceiling.

[wmoses]

Pictures?