# shed roof slope



## Ron6519 (Mar 28, 2007)

crhage said:


> ok, so will a 1' slope be sufficient on a 13' run on a shed style roof attached to the side of my house? I'm in SC. Hardly any snow; mostly rain. What would you recommend? That is about the max. I might be able to squeeze 1.5'.


It's under the 1/8" per foot slope required for water shedding. I'd try to get a little more slope if you can.
What roofing material will you be using?


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## crhage (Jun 4, 2011)

It'll be a shingle roof. 

So I was thinking of attaching the ledger to what I hope is a header that runs along the top of the windows on the outside of my house (I hope the builders used a header all the way across). If I don't do that, is it acceptible to attach the ledger to the wall top plate or to the studs that are between the windows and the top plate (beneath the soffit)? If I can attach the ledger to the studs (or even the top plate) I can get an additional 1.5' slope for a total of 2.5 feet of slope.


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## Ron6519 (Mar 28, 2007)

crhage said:


> It'll be a shingle roof.
> 
> So I was thinking of attaching the ledger to what I hope is a header that runs along the top of the windows on the outside of my house (I hope the builders used a header all the way across). If I don't do that, is it acceptible to attach the ledger to the wall top plate or to the studs that are between the windows and the top plate (beneath the soffit)? If I can attach the ledger to the studs (or even the top plate) I can get an additional 1.5' slope for a total of 2.5 feet of slope.


Shingles require a minimum 3 in 12 pitch. If you can't achieve that, you'll need another plan


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## crhage (Jun 4, 2011)

sorry to be ignorant, but how do I calculate that? 

Can I attach the ledger to the studs? Or attach it to the top plate?


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## Ron6519 (Mar 28, 2007)

crhage said:


> sorry to be ignorant, but how do I calculate that?
> 
> Can I attach the ledger to the studs? Or attach it to the top plate?


 For a 13' horizontal run(length), you need a 39" (3 feet, 3 inches)drop to install shingles.


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## crhage (Jun 4, 2011)

nevermind, got it figured out (I think). In order to have a 3 in 12 pitched roof, over a run of 14 feet I would need the roof to drop 3.5 feet. 

I KNOW there are shed style roofs with shingles in my neighborhood that are not 3 in 12 pitched roofs. If I add a water and ice shield under the shingles, what do you think?


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## Ron6519 (Mar 28, 2007)

crhage said:


> nevermind, got it figured out (I think). In order to have a 3 in 12 pitched roof, over a run of 14 feet I would need the roof to drop 3.5 feet.
> 
> I KNOW there are shed style roofs with shingles in my neighborhood that are not 3 in 12 pitched roofs. If I add a water and ice shield under the shingles, what do you think?


Water will probably get under the shingles, but won't get down to the wood sheathing.
People build things incorrectly all the time. Just because many people do it, doesn't make it correct or acceptable.


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## loneframer (Mar 27, 2009)

I've seen shingles done on about 2.5"/12". The felt has to be double coverage and the shingle exposure is reduced by 20%, or 1".

12" of rise over 13' is only .923" per foot, or about 15/16"

Shingles are not a good option.

I'd consider a hand laid fiberglass mat/resin with a UV gel coat or a poly urea/urethane spray down. These surfaces are considered walkable and you could use it for a nice second floor deck.

If neither of these are available in your area, there are other roofing materials more appropriate for a flat roof, which at under 1" per foot, yours essentially is.


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## crhage (Jun 4, 2011)

Thanks everyone. Please read the rest of my question. I have enough room to do a 2/12 or even a 2.5/12 pitch *IF I can bolt the ledger to the studs or top plate of the exterior wall.* I will be checking with my building permit office, but wanted to know if that is generally acceptable. Is it? 

Also, I've read that a water and ice barrier is a suitable underlayment under shingles on a pitch that is 2/12.


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## Ron6519 (Mar 28, 2007)

crhage said:


> Thanks everyone. Please read the rest of my question. I have enough room to do a 2/12 or even a 2.5/12 pitch *IF I can bolt the ledger to the studs or top plate of the exterior wall.* I will be checking with my building permit office, but wanted to know if that is generally acceptable. Is it?
> 
> Also, I've read that a water and ice barrier is a suitable underlayment under shingles on a pitch that is 2/12.


You can bolt the ledger into framing members. Studs and top plates are framing members.
The roofing requirements will not be followed with the projected pitch, so there will be no shingle warranty. But with the ice and water shield, you should be water tight.
There's a good possibility the roof will not last as long as it would with the proper pitch.


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