3 sided shed

[JMER817]

I' m planning on building a 3 sided shed or run-in shed that some might call it. Will be using rafters sloping the roof from 8' in front to 6.5' in the rear. Span will be 12' with 16" on center. Debating on size of rafter. Live in Michigan with snow in winter. Thinking 2 x 8 will suffice?

 

[chinton]

There's a neat app on iPhone from the American Wood Council call Span Calculator that can give you that information. Depends upon the lumber selection you've got available and the snow load you need to design for. Also some of our cities around here publish a specific span chart to be used in their jurisdiction. Even if you aren't covered by their regulations, it's a good reference.

 

[EddieWalker]

In the grand scheme of things, going up to 2x12's will only add a hundred bucks to the entire building. Why not use the strongest material readily available?

 

[Billrog]

2x8's will be plenty strong enough for rafters.

 

[Creamer]

2x8's will be plenty strong enough for rafters.

Agreed! I don't live far from you and expect you have a 30 pound snow load.

 

[newbury]

I' m planning on building a 3 sided shed or run-in shed that some might call it. Will be using rafters sloping the roof from 8' in front to 6.5' in the rear. Span will be 12' with 16" on center. Debating on size of rafter. Live in Michigan with snow in winter. Thinking 2 x 8 will suffice?

Distance from front to back determines slope with a 1.5' drop. Will it be steep enough to shed snow?

Grass Lake looks like it calls for a 30 lb psf snow load. Parts of northern Michigan show a 60 lb psf snow load.

Also take into account how strong the winds can get. Like Eddie wrote a little overbuilding wouldn't hurt much.

 

[JMER817]

In the grand scheme of things, going up to 2x12's will only add a hundred bucks to the entire building. Why not use the strongest material readily available?

I usually get a laugh out of my friends because I over-build things. This is going to be on the edge of the woods mostly hidden from the house down in a small gully. Just going to cover my wood splitter, brush hog, and other garden tools.

 

[Budweiser John]

I usually get a laugh out of my friends because I over-build things. This is going to be on the edge of the woods mostly hidden from the house down in a small gully. Just going to cover my wood splitter, brush hog, and other garden tools.

I would seriously consider adding the fourth side with doors.
My south facing open sided shed is about worthless for weather protection in a driving rain or blowing snow.
No issues with 2x8 16 centers. Might want to add some X bracing mid span for some added oomph but consider
Some closure on the open side,
B/4 this winter, I'm putting doors on my open shed.

 

[efam3300]

12' is the max span on 2x8 joists on a sub-floor, thats not taking in account the snow load

 

[Midniteoyl]

According to Span Options Calculator for Wood Joists & Rafters , the minimum for a 12' span, 16" center, with a 40lb/sf snow load (this is Michigan, after all) using No.2 SPF wood (Spruce-Pine-Fur, typical wood) is 2"x8". I believe your area requires at least a 30lb/sf snow load rating, so you should be good to go using the 2x8's. If you used 2x10's, you could get the same rating @ 24" spacing.