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-   -   Shed roof framing - rafter size recommendations? (http://www.diychatroom.com/f14/shed-roof-framing-rafter-size-recommendations-177111/)

tpagel 04-14-2013 10:40 AM

Shed roof framing - rafter size recommendations?
 
I am planning on building an 8'x12' shed this summer. It will sit on a portion of my compacted gravel driveway and have a single plane, sloping roof (shed roof). The front face of the shed will be 12' long, have a 6' width of double doors, and be approx. 10' high. The rear face will be approx. 8' high. My question is: Many shed kits use 2x4's at 24" O.C. to frame their roofs, usually with a gabled truss. Since I live in CT, and plan on a simple shed roof, am I better served using 2x4's at 16" O.C. for the roof (with cross blocking for more rigidity), or 2x6's at 24" O.C.? I am opting for the 2x6's, so I can create a birdsmouth connection at the top plate, but I don't want to spend money unnecessarily. Are 2x6's overkill? I did have 4' of snow on my roof this winter... :(

Thanks for all advice.

funfool 04-14-2013 11:23 AM

Go with the 2x6, 2x4 make a really crappy shed roof. They are great for a engineered truss system.

What you really need to do is check the span of the 2x6 and the load calcs of what it will hold. Then figure out what 4 foot of snow weighs.

I would not consider 2x4
2x6 would be the bear minimum I would use.
You may find with your load calcs that the weight of the snow is pushing the limits of the 2x6. You may want a 2x8.

I only have memories of snow living in Albuquerque :laughing:
Seems to be a big difference in weight from a nice fluffy dry snow, to a wet heavy snow.
If you ever think you may want to putter around in the shed during the winter, will be able to add more insulation with the 2x8.
Here we use 2x12, not for strength, just to meet code for insulation in a living space.

joed 04-14-2013 11:29 AM

2x4 in the form of a truss does compare in any way to a 2x4 used as a straight rafter. For a 12 foot span a 2x8 is called for.

jagans 04-14-2013 11:49 AM

A truss is designed to break down applied loads and distribute them throughout the truss to the foundation. A single span rafter has to deal with the applied loads within its structure. You may want to re-think the 8 foot dimension if you can, that's pretty shallow.

GBrackins 04-14-2013 12:18 PM

two questions, what is the ground snow load requirement for your area, and what is the slope of the 8' span shed roof?

tpagel 04-14-2013 01:39 PM

Thanks everybody....The ground snow load where I live is 30 psf. I think the slope of the roof will be about 3:12. I chose the 8' depth of the shed for floor panel material efficiency. The 4' of snow on the roof of the house has happened twice in 5 years, but the shed is easily cleared with a roof rake, as opposed to the house, whose roof we had to shovel.

GBrackins 04-14-2013 02:42 PM

for 30 psf snow load, 3/12 pitch roof over a 8' span the minimum rafter would be something like a #2 spruce 2x6 at 16" o.c. I'd strongly recommend 2x8 at 16" o.c. however. the difference in price isn't that much for your shed, and you'd have a stronger roof for those high snow events.

just my opinion

tpagel 04-14-2013 07:51 PM

Sound advice. I'll go with 2x8's at 16" O.C. for the rafters. I appreciate everybody's help!

jagans 04-14-2013 09:06 PM

Quote:

Originally Posted by tpagel (Post 1159052)
Thanks everybody....The ground snow load where I live is 30 psf. I think the slope of the roof will be about 3:12. I chose the 8' depth of the shed for floor panel material efficiency. The 4' of snow on the roof of the house has happened twice in 5 years, but the shed is easily cleared with a roof rake, as opposed to the house, whose roof we had to shovel.

If you have the room, I would double it to 16 feet. Stuff Grows :eek:

Gary in WA 04-15-2013 12:48 AM

http://publicecodes.cyberregs.com/ic...002_par023.htm

Gary

hand drive 04-15-2013 08:20 AM

Quote:

Originally Posted by tpagel (Post 1159329)
Sound advice. I'll go with 2x8's at 16" O.C. for the rafters. I appreciate everybody's help!


might want to plan on some overhangs with your rafters that go past the top plates then connect the rafters to the top plates with hurricane clips...


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