How to fix roof leak in new work?


Old 07-23-15, 04:46 PM
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How to fix roof leak in new work?

Here is the whole story. It is an enclosed porch about 7x12 used as a laundry room. It has always been leaky. It has some slope--not sure how much. It is not nearly a flat roof.
I replaced the sheathing, laid down roofing paper horizontally, then roll roofing the same way, followed by shingles to cover the roll roofing. All layers go under the adjacent roof of the house. At the edges there is also an additional strip of asphalt.
It successfully sealed the room in the worst storms so far ( the drought has hampered my troubleshooting efforts), but it leaks at the outer wall in one spot. Part of my frustration is it is not apparent whether it is leaking through the roof or the wall. It only leaks in an extreme storm when the rain is coming at it horizontally.
There were some cracks where the rafter comes through the wall, so I sealed that up. It did not stop the leak. I also opened up a small section of the drywall to expose the roof and wall in that area. But there is no darkening of the wood.
The leak is not enough to drip. The evidence of it is bubbling of the paint and the drywall feels moist underneath the bubbles. The bubbling does not go all the way to the roof but stops about 3 " below. This suggested a wall leak but I have sealed the cracks as I already stated. The wall is 2x4 frame with vertical plywood siding.
I have considered stuffing tar under the area but I am afraid of just making a mess or damaging the roofing. What are some good ideas to deal with an evasive leak like this one, either to troubleshoot it or to cure it?
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Old 07-23-15, 04:52 PM
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Right off the bat I would say rolled roofing and/or shingles are not the correct roofing material. They need a fair pitch to the roof in order to shed water. I would say you need a membrane like used on flat roofs. That will address possible issue with the water coming through the roof. Then it's just good roofing and flashing practices to seal where it meets your house or other roof.
Old 07-23-15, 06:41 PM
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How did you I stall the dripedge? On gables (sloped sides) it should be installed over the underlayment. On the horizontal eaves it should be under the underlayment.

If the pitch is 3/12, the felt should be installed in a half lap, and depending on manufacturer may require additional nails and less exposure.....

If less than 3/12 a built up modified roof or rubber should be used. There are also low slope product available such as Flintlastic that may be an option.

"Stuffing tar" is just a band-aid, and will eventually fail if not maintained.

If roof intersects a wall or a chimney was the proper counterflashing installed? Without photos it may be tough to diagnose, but hopefully this may give you a place to start....

Last edited by Perryjr84; 07-23-15 at 07:53 PM.
Old 07-23-15, 07:58 PM
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Old 07-23-15, 08:41 PM
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Really need those pictures up on the roof.
I agree 100% makes no since to have used roll roofing.
99 percent of the time it's a flashing issue if that roof meets a wall.
I would not have used rolled roofing on a dog house.

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