Leak around furnace vent pipe in roof

Old 12-02-13, 06:26 PM
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Leak around furnace vent pipe in roof

I've attached a picture of my roof. When it rains really hard, I've noticed water running down the outside of this pipe in my attic. Seems like I just need to seal the outside of the pipe with some caulking or something, right?

I'm wondering a couple things. I want to be able to get up to the pipe without damaging the tiles on my roof, which are metal. Or damaging myself, for that matter -- the roof is fairly steep, although I think I should be fine on a non-windy day. When I had an antenna installed, the guys who installed it mentioned that you had to be careful walking on this kind of roof to not dent the tiles. I'm guessing that means walking on the edges of the tiles only, but I wanted to confirm.

Also, I'm not sure what kind of sealant would be best to use. I live in Wellington, New Zealand, and the weather here is pretty humid, and it rains a lot, have very high winds at times.

Thanks much in advance,

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Old 12-07-13, 06:50 PM
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I would hire someone to do the job especially if you aren't accustomed to that pitch. Some roofing cement/tar should work.
Old 12-10-13, 03:11 PM
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Metal roofs do not tend to lend to easy walkability.

Check the seams in the vent as well.
Old 12-11-13, 12:59 PM
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Caulk is actually not a long term fix for leaks. It seals out wind and air and has some limited value in protecting against horizontal water intrusion from wind driven snow or rain. But it was never actually meant to serve as a first line of protection from direct water intrustion in this scenario. That is what flashing and vent boots are for. If that stuff is properly installed and in good shape, minimal or no caulking is required. The flow of water will be directed so it continues around roof junctions and protrusions without focusing its pressure on the vulnerable seams and cracks.

Don't get me wrong. If you want to try to caulk it you can. The water will just force its way through again. Instead of not having to touch it for several years you will have to get up there and periodically apply new caulk. Another problem with trying to use patching substances is you are in a kind of damned if you do, damned if you don't scenario...you usually have to use alot to stop serious water intrusion. But by doing so the built up surface can trap water that normally flows smoothly down the roof and hold it there until it finds its way in somewhere else, leading to more leaks.

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