Rafter size??

[Adam Vernott]

Can someone figure out what size rafter I need for my new garage I want either 2x10 or 2x12, whitch one??
Metal roof on 1" boards
Live in central Maine
Garage is in the open
32'x50'
4/12 = slope
1' overhang

 

[mtlogcabin]

Species and grade of lumber? 12", 16" or 19.2" rafter spacing?
Ground snow 50 or 70 PSF?

 

[cda]

Welcome

Love me some lobster

 

[ADAguy]

span exceeds member size.

 

[SCBO1]

Is the garage clear span, or does it have post or beam?

If post and beam the rafter span can be reduced when using purlins if continuous and supported to bearing, see IBC2012 section R802.5.1

See figure R802.5.1

 

[rogerpa]

See Table R802.5.1(8) https://codes.iccsafe.org/public/document/IRC2015/chapter-8-roof-ceiling-construction. You may have to have engineering if your ground snow load exceeds 70 psf. See Figure R301.2(5). https://codes.iccsafe.org/public/document/IRC2015/chapter-3-building-planning