buckeyefarmer
Epic Contributor
See post 5
Need help figuring out barn extension
- Thread starter petebert
- Start date
- Views: 9165
I'm getting confused here, any pictures of these options? As far as the siding/wall. I'm removing all of the siding. Once the extension is built it will be part of the open area inside the barn. There's a 6x6 post spaced every 10-12 feet. There's 2x4 girts between them for the siding to attach to but those aren't needed for any structural integrity right? The header boards provide all the structural support needed right?
As far as notching them, the existing ones are notched, why couldn't the new ones be notched too ? That being said I'd prefer to not have the extra workload of doing that.
As far as adding a new ledger board or new header. What's confusing me there is I had planned on making the new roof be one continuous roof with the existing roof. So wouldn't the rafter have to line up with each other. So when I picture this in my head the new ledger/header can't be lower than the existing one. On the other hand, if I build a 2nd roof a few inches below the existing I wont have to remove my existing gutters or soffits. And this sounds like a super easy build to me, attach a ledger, use some hangers and your good.
As far as notching them, the existing ones are notched, why couldn't the new ones be notched too ? That being said I'd prefer to not have the extra workload of doing that.
As far as adding a new ledger board or new header. What's confusing me there is I had planned on making the new roof be one continuous roof with the existing roof. So wouldn't the rafter have to line up with each other. So when I picture this in my head the new ledger/header can't be lower than the existing one. On the other hand, if I build a 2nd roof a few inches below the existing I wont have to remove my existing gutters or soffits. And this sounds like a super easy build to me, attach a ledger, use some hangers and your good.
EddieWalker
Epic Contributor
When notching the birds-mouth at the bottom of the rafter, you are going from the full width of the board on the strong side, and carrying it over the top plate, or beam. When you go the other direction, and notch the birds-mouth at the top, you have made the thickness of the board what you cut it. To add to the board now being thinner, it is also tremendously weaker due to the tendency to crack at the birds-mouth cut.
buckeyefarmer
Epic Contributor
Like this.
buckeyefarmer
Epic Contributor
bottom cut, full board still supports weight.
top cut, uncut part of board supports all weight, cut half part, if unsupported, carries no weight.
buckeyefarmer
Epic Contributor
The way i showed keeps the same roofline as existing. The new outside rafter is lower because your existing rafters are notched.
So let's talk about the option of adding a 2nd roof instead of it being a continuous roof.
Pros - I don't have to disassemble my soffit, fascia and gutters which are all still nice and tight and in good shape.
Cons - I lose 1' of height and in snow country this is important for maintaining slope rate. I'm far enough south in Michigan that I can use a 4/12 pitch. So starting height of 11', end height of 7', 12' wide extension and I have a 4/12 pitch. Although this means no overhang at all. This is a livestock barn and the extension is going to be a sheep barn. The sheep don't care how tall it is but I figure I can get away with 7' tall at the end to still be able to maneuver comfortably as a human and could even get a compact tractor into the door.
From the ground to the bottom of my soffit is 11'6". So as I sit here and do the math. I first have to take off a few inches for a flashing, I'll have to check the span tables but lets say 2x12 rafters, I'd really end up at only 6' tall at the end. Now knock off a couple inches for a door frame and it's not much of an opening.
Looks like I can use 2x8's for a 12' span with 16" spacing.
Pros - I don't have to disassemble my soffit, fascia and gutters which are all still nice and tight and in good shape.
Cons - I lose 1' of height and in snow country this is important for maintaining slope rate. I'm far enough south in Michigan that I can use a 4/12 pitch. So starting height of 11', end height of 7', 12' wide extension and I have a 4/12 pitch. Although this means no overhang at all. This is a livestock barn and the extension is going to be a sheep barn. The sheep don't care how tall it is but I figure I can get away with 7' tall at the end to still be able to maneuver comfortably as a human and could even get a compact tractor into the door.
From the ground to the bottom of my soffit is 11'6". So as I sit here and do the math. I first have to take off a few inches for a flashing, I'll have to check the span tables but lets say 2x12 rafters, I'd really end up at only 6' tall at the end. Now knock off a couple inches for a door frame and it's not much of an opening.
Looks like I can use 2x8's for a 12' span with 16" spacing.
Cord
Veteran Member
You just put all the shed roof load in shear on the beam spanning between the posts. You also doubled the load on that member without any consideration of it's bearing capacity.
downsizingnow48
Elite Member
The last photo appears to show the inside 2x12 nailed to the post with five nails?