1/2" OSB or 3/4" OSB for roof?

[Wxguru]

Going to be taking care of the roof for our new coop this week. I have a roof that is going to be about 10'X8'. That will leave a 13" overhang on each side, and about 22" front to back (lean to style). Frame will be using 2x4x8's and 2x4x10's with approximately 8 rafters in there. I will lay down the OSB sheets, and then a 15LB asphalt roof sheet and then shingle the roof as you would a normal roof (slope will be about 2.5/12). Rafters will be attached with hurricane straps.
With that being said, would I be alright going with 1/2" OSB or do I need to go with 3/4" OSB? Trying to keep some of the weight down a bit but maintain strength and keep from any compromise.
Also, necessary to use PT or can I go with studs?
I do plan on putting a drip edge, and gutter on the back as well and drain water away from the coop (it is a sloped area).
Thanks for all the help!!

 

[mississippifarmboy]

You only need PT lumber if it's in contact with the ground. And personally I'd rather use 1/4" plywood as 3" OSB. But that's just me, I hate the stuff.

If the rafters are 16" OTC I'd say 1/2" would work though.

 

[chicksurreal]

We used 3/4" OSB for ours, but our coop is pretty big and we didn't want any sagging, so we thought supports every two feet on center and 3/4" OSB would work. We are also using asphalt shingles.

 

[Wxguru]

My rafters will be on 20" center....and asphalt shingles.....I might split the middle and go 1/2". 1/4" just seems so thin

 

[chicksurreal]

My rafters will be on 20" center....and asphalt shingles.....I might split the middle and go 1/2". 1/4" just seems so thin

Yeah, I think 1/4" would be flimsy. That's my uneducated opinion.

We are glad we went with 3/4", but we probably could have used 1/2" with no problem. Our roof is 16' x 10' and we wanted to make sure it would hold up.

 

[MeepBeep]

Since you are in Arkansas and don't have to factor in a a heavy snow load you will be plenty fine with 1/2" OSB sheeting on the roof, with up to 24" rafter spacing no problem, surprisingly 1/2" OSB on 24" centers is actually snow load rated and up to code in many places... Do note though, you might see some bow in between the rafters, but this is common in this application, and because of this to avoid one sheet bowing and the other not creating a gap, you can install panel clips (H clips) in between the rafters to help avoid this by tying the two sheets together, it's standard practice and code in most areas to do so...

http://www.menards.com/main/tools-h...ements/miscellaneous/plywood-clips/c-8874.htm

 

[Wxguru]

Any issue with 22" overhangs on front and back? Sagging concern? Want to find out now, rather than when it happens and I have to come up with a new plan.

 

[MeepBeep]

Any issue with 22" overhangs on front and back? Sagging concern?  Want to find out now, rather than when it happens and I have to come up with a new plan.

Are they supported overhangs aka are the rafters extending out that far as well? 24" overhang is normal for modern house/garage construction...

 

[Wxguru]

Rafters will go the full distance to the actual roof frame....attached....

 

[MeepBeep]

Frame your overhangs like this and you won't have any issues, even at 24" spacing with 1/2 (or even the cheaper 7/16) OSB...