Roof Pitch for Standard Shingles

[a12vman]

I am having some trouble with the roof on the rear of this house.

http://65.31.50.236/pub/roofpitch.jpg The rear roof is standard 3-Tab Shingle over 15# Paper and OSB, probably about 4 Years Old.

I was up in the attic the other day towards the rear pitch and the OSB is saturated with water to the point that it is dripping on the insulation below(Snow piled on the roof). There is sufficient venting in the attic. I want to fix the problem on the rear roof but am not sure how to keep the water from penetrating given the gentle slope:

1. Tearoff, new osb, ice guard over all the sheathing, 30-Year Shingles.
2. Tearoff, new osb, Rubber Roof?

Thanks in Advance, -a12vman

[tom]

The pitch looks fairly close to flat deck material applications. Is that a valley dumping onto it from the left? Tom

[a12vman]

No the gabled roof sets in front of the flat roof, the runoff is caught by the gutter.

[tom]

Option 2, anyways. New flashing up and under the siding, too. Tom

[Joseph Meehan]

My guess is the flashing at the top where it meets the wall has a problem or is totally missing.

[Ken]

I agree with Joseph, the flashing is probably done poorly or missing.

Ken

[barry]

Actually, looks more than 1 in 6 pitch, to me, the lower limit for

3-tab. J

[dp]

Seen this problem many times

[mm]

Instead of your eyeballing it, and others of us who don't want to being expected to go look at a file, why didn't the OP just measure it and tell us?

Remove NOPSAM to email me. Please let me know if you have posted also.

[RicodJour]

No need. From the scale of the door and the window on the side the addition is roughly 8' deep. Count the number of 4" courses of the vinyl siding. The rise is roughly six courses (24"). 24"/8 = ~3" rise in 12" > ~3/12

It's definitely at the very low end of what's acceptable for 3-tab shingles. With such a gentle pitch I would have covered the entire roof with Ice & Water Shield before shingling.

To the OP: you are the proud owner of a classic, roof wide ice dam. Strip the shingles, inspect the OSB (if it's really that saturated, it may have a lot of rot and be too far gone to save - replace as necessary), check the flashing at the top end to make sure the schmucks didn't cut corners up there, too, install Ice & Water Shield or Weatherguard underlayment with aluminum drip edging along all roof edges, shingle.

R

[Dan_Musicant]

On 14 Dec 2005 19:29:40 -0800, "RicodJour" wrote:

: :mm wrote: :> On 14 Dec 2005 12:47:25 -0800, [e-mail] wrote: :>

:> >Actually, looks more than 1 in 6 pitch, to me, the lower limit for :> >3-tab. :>

:> Instead of your eyeballing it, and others of us who don't want to :> being expected to go look at a file, why didn't the OP just measure it :> and tell us? : :No need. From the scale of the door and the window on the side the :addition is roughly 8' deep. Count the number of 4" courses of the :vinyl siding. The rise is roughly six courses (24"). 24"/8 = ~3" rise :in 12" > ~3/12 : :It's definitely at the very low end of what's acceptable for 3-tab :shingles. With such a gentle pitch I would have covered the entire :roof with Ice & Water Shield before shingling. : :To the OP: you are the proud owner of a classic, roof wide ice dam. :Strip the shingles, inspect the OSB (if it's really that saturated, it :may have a lot of rot and be too far gone to save - replace as :necessary), check the flashing at the top end to make sure the schmucks :didn't cut corners up there, too, install Ice & Water Shield or :Weatherguard underlayment with aluminum drip edging along all roof :edges, shingle. : :R I would have guessed 3/12, but RicodJour came to the rescue and proved it. For the shingles just installed on my roof (Elk), 3/12 is acceptable but only if they use double underlayment. In fact, my roofer didn't do that and I made him tear off a section that I measured at 2.7/12, and install double underlayment. Water shield is also a good idea. If your roof is still under warranty, you might be able to get the roofer to repair this, especially if it wasn't installed in accordance with shingle manufacturer's installation specifications, which was the case with my roof.

Dan