rafters for a 30' X 60' building

Discussion in 'General Discussion' started by melbo, Sep 10, 2005.


  1. melbo

    melbo Hunter Gatherer Administrator Founding Member

    monkeyman asked me what he needed and the best way tell him is to post this thread... btw, I had to use an (idiot program) for the picture because I'm too lazy tonight to fire up Chief Achitect to draw the pics...

    30 X 60 building

    3/12 pitch, Thats 3" rise for every 1' of run, run=half the span so 15'. I went with a typical 12" overhang. It made your rafter longer than 16 so I cut it down to 7" overhang.

    You will need 46 2" X 8" rafters per side of the roof 92 2X8X16s total

    Forget about the center wall being load bearing, not needed, you can put a wall there if you want but the rafter span is self supporting...

    Ridge is also 2x8 and you need enough 2x8 to run the 62' so get 3 12' and two 14'

    The metal roofing is running me $1.60 a linear foot right now..High dollar stuff.

    Material list to price by:
    92) 2" X 8" X 16' rafters
    3) 2 X * X 12 ridge
    2) 2 X 8 X 14 ridge
    60 sheets 7/16 OSB for roof deck

    Felt, shingles or metal as needed

    The below pics show EVERY cut you need to make these rafters
    rafter2_792. rafter_130.
     
  2. ghostrider

    ghostrider Resident Poltergeist Founding Member

    To have a 2 foot overhang under the gables, you need four more rafters, 2X4 s for barge rafters, and four more sheets of plywood. For a 30 foot span, I would probably build my own trusses out of 2X4s, lighter and cheaper.
     
  3. melbo

    melbo Hunter Gatherer Administrator Founding Member

    I can see 2 more 2x8s for rafters, Were not building barges and 2 more sheets plywood... I was giving him a 7" overhang all around to keep the symetry... So, 62ft X 16 ft =992 ft, divided by 32sqft, is 31 sheets per side.

    I know that he will have to go back to the yard for something and I think it's better to have to pick up a few more items than have to take back a few. :D

    by Barge rafter, are you talking about outlooker or outrigger 2x4s? running parallel to the 60' side to support the fly rafter? Some of the terms have changed over the yrs....
     
  4. Quigley_Sharps

    Quigley_Sharps The Badministrator Administrator Founding Member

    Looks great to me, when we going to build it? b::
     
  5. melbo

    melbo Hunter Gatherer Administrator Founding Member

    edit, It hit me this morning that ghost was right about the 4 extra rafters. I did not account for the Fly rafters. Still think my Sheathing math is good though... [beer]
     
  6. ghostrider

    ghostrider Resident Poltergeist Founding Member

    I automatically figured a 2 foot overhang, so you were correct.
    16 + 16 =32, the hypoteneuse of the triangle. 32 is the square footage of one sheet, so the length of the roof gives the number of sheet. I had added 2' on each end, 34 sheets.
     
  7. melbo

    melbo Hunter Gatherer Administrator Founding Member

    I run 2 foot overhangs on all of my builds. But I use 18' 4X8 rafters. I tried to shrink mms down so he could get by with a 16' rafter

    On my stuff, I have a 26' OZ span so I actually have to cheat my 12/12 down to 11.72ish to make it without jumping up to a 20' rafter
     
  8. ghostrider

    ghostrider Resident Poltergeist Founding Member

    Oops, didn't explain barge rafters. A barge rafter holds the fly rafter up. If your rafters are on 24" centers, then the barge will be 48" - 1 1/2 ". It will be inletted into the last rafter sitting on the top plate, and nail into the fly and the next to last rafter. The fly rafter is nailed into the ridge and probably two barge will hold it until you can staple the OSB down.
     
  9. melbo

    melbo Hunter Gatherer Administrator Founding Member

    that's what I thought. In a roof truss situation, you notch a 1.5" x 3.5" slot in the Gab;le truss, Around here, they call them Outlookers.. hillbillies
     
  10. monkeyman

    monkeyman Monkey+++ Moderator Emeritus Founding Member

    Soon as I can come up with a few grand that dont have to go to food, utilities, land payment or fuel, so that I can go get the materials. :D
     
  11. ghostrider

    ghostrider Resident Poltergeist Founding Member

    Door.
    redneck_carpenters_517.
     
  12. melbo

    melbo Hunter Gatherer Administrator Founding Member

    That's got to be photo shopped...
     
  13. melbo

    melbo Hunter Gatherer Administrator Founding Member

    Damn tree is upside down! BIng
     
  14. ghostrider

    ghostrider Resident Poltergeist Founding Member

    b::
     
survivalmonkey SSL seal        survivalmonkey.com warrant canary
1NTzCYzfQp3EJAGcxRodMHQMXm1u9pVTCT