# Sun tunnel leaking



## hr_veedu (Dec 2, 2014)

Hi Guys,

Wanted to get expert opinion to see if I'm on the right track on this one. I have 3 pictures that shows the inside and outside. It seems to be a flashing on top of which the sun tunnel tube is mounted using 4 screws. There is a hard rubber gasket that seems to holding the tube down to the flashing on the roof. Water drips from this rubber gasket which can be seen in the third picture. 

I attempted to seal the outside flashing to tube mount with a Loctite s30 but rained played spoilsport. I'm wondering if I sealed this is good weather, it would solve the problem or I'm missing something more fundamental?

Thanks very much for any opinion!


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## oldognewtrick (Dec 2, 2014)

Well, I've seen 

a lot of creative thinking when a roof penetration is made, but that a first. Who and when was it installed? How long has it been there? And do you know the MFG of the skylight?

The first thing to check is to find out where it's leaking. This can be done using a garden hose and work from the bottom up till you find the leak. Have a helper stand inside and slowly move the water till you make it leak. 

If I were to use caulk, I'd use Dow 795, Geocel or a tri-polymer based caulk. Don't use pure silicone.


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## hr_veedu (Dec 2, 2014)

It was installed by the previous owners. I think definitely 10+ years old. Can't seem to find any name on it either which is not helping. I don't have a helper around, so, it has been hard doing any kind of live testing on it. 

Water seems to be dripping along the outer edge of the rubber gasket at one or two points. The only connection to the outer world seems to be where the tube is screwed into the roof metal flashing. I would have to try some kind of sealant on the outside tube-flashing joint once the weather improves -- I just can't see how else the water would make it in .

P.S I used this http://www.loctiteproducts.com/p/pl...-S30-Polyurethane-Roof-&-Flashing-Sealant.htm. The only catch is that rained before it could settle in for 24 hours.


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## oldognewtrick (Dec 2, 2014)

Can you get a better pic of the exact location where the leak occurs?


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## joecaption (Dec 3, 2014)

Considered installing a real sky light?
That one has 0 insulation or UV filtering.


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## hr_veedu (Dec 3, 2014)

I went up there and took a picture. Not much rain now. The outer view shows two lines: red -- tube joint with the roof flashing (there was some kind of black seal which looked worn out, which I what I attempted to reseal), green -- there is no joint there but there is a hard rubber gasket on the inside which is shown in the second picture.

The second picture again shows these two lines to indicate where they are in perspective (green is showing as white). The blue circle shows water droplets; they bubble through the inside of the gasket and the reflecting metal surface.

Hope this gives a better picture. Thanks again for your time!


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## hr_veedu (Dec 3, 2014)

Hmm... I disconnected the flexible tube that acutally connects down to the ceiling to better spot the leak. Not sure if your comment would change considering this additional detail.


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## slownsteady (Dec 3, 2014)

Is the leak (blue circle) on the downhill side of the tube? Is it actually "bubbling" or is it seeping slowly?


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## hr_veedu (Dec 3, 2014)

It is on the downhill slope.. it slowly seeps and accumulates as one droplet at the exact edge of the most downhill point of the tube circle (under gravity). As I mentioned earlier, i tried to seal with a polyurethane roofing sealant, but the rains have been non-stop and probably there was no time for the seal to set .

Ironically, the other exactly identical sun-tunnel in my house started leaking too. Wonder if the seals were supposed to last an exact number of years . I can't check on this one yet, this one is in a less accessible section.


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## nealtw (Dec 3, 2014)

Are you sure this isn't condensation, if warm moist air can get in the tube, just a thought.


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## hr_veedu (Dec 3, 2014)

The water seems to be seeping through very slowly, doesn't look like condensation although I initially was hoping that it was. And additionally, 
it happens only when it rains; first time around it collected quite a bit of water in less than a few hours. After I put in my round of sealing (which didn't set well though), the leakage has reduced to a droplet in a few mins.

The red line in my picture seems to be the only moving part through which water can get in. If I seal that right, in theory, would that be the right direction? 

Thanks again!


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## nealtw (Dec 3, 2014)

The leak would have to be on the top half which is usually protected by shingle that are cut closer to the riser. Maybe you could work in some flashing under the shingles and over that seam on the top half.


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## slownsteady (Dec 3, 2014)

I would try a bead of caulk again. You should take off the old bead (your last attempt) and take your time to be sure you aren't leaving any gaps. If rain is predicted, cover the tube with a plastic sheet, which you can remove after the caulk has cured. There may be a more complicated reason why this is leaking (shingles, flashing etc. ) but at least you will stop the leak until you or a pro can find a long-term solution.


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## hr_veedu (Dec 4, 2014)

Thanks for all the input. I will give the sealant another try once the weather improves and see if that works.


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## joecaption (Dec 4, 2014)

That cheap light is always going to be a issue, it needs to go.


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## slownsteady (Dec 4, 2014)

Well, I guess that would qualify as a long-term solution


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