Need help figuring out barn extension

[petebert]

I want to extend the sloped sides of my barn. I've built all sorts of stuff, just nothing quite like this so I don't know the best way to put it together. If I could get some design ideas or a picture of how it should go together, I can build it no problem. Also let me know if my terminology for any of the parts is incorrect.

The gutters/bottom of soffit sit around 12' above the ground. I want to take that down to around 7'. What I'm not sure about is how to tie into the existing structure. I'm going to post some pictures below to show the existing structure. Let's start with the fascia board, that's probably just nailed into the rafters. So that's not weight bearing at all right? Could I put some hangers onto them and make them weight bearing. Then just hang the rafters for the new roof on the opposite side? Or will I need to take the fascia board off and rest the new rafters onto the same beam that the existing ones are resting on. The existing rafters are notched and resting on the beams, also nailed in but I'm not exactly sure how they're nailed in, they're in a tough spot to get a good look at. All the boards are 2x12's, I know some of you guys know the pine span tables pretty well so let me know if I need to double up any of the beams let me know. This will be in SE Michigan so the concern is snow load and if the new roof adds weight to the exisiting roof.

 

[buckeyefarmer]

Take fascia off, put new rafters so top is same as old truss top. End of new rafter against wall of building with a new header under it for load support. New header bolted to existing barn posts. Or maybe you can use hangers from existing barn header for new rafters, if right size.
Im planning to do the same soon.

 

[buckeyefarmer]

And dont hang anything but a gutter from the fascia.

 

[petebert]

Could I notch the new rafters, set them on the existing header and then nail the new rafters to the existing rafters?

 

[buckeyefarmer]

Only if the new rafters are supported from bottom also. Notching at the top end of rafter, so it hangs from the notch takes away from load capacity. You can notch at bottom end of a rafter without losing capacity if notch bears to the bottom of the rafter.
Are your existing headers bolted, or just nailed to the poles? From picture i didnt see a bolt.

 

[Streetcar]

By extending the roof, you are increasing loads on the existing post and headers. You need to verify that the existing materials and connections are satisfactory for the increased loads.
Never attach structural members to fascia

 

[radioman]

here is my 2 cents -- i wouldnt cut your new rafters and make it fit inside of the truss carriers you already have. the new rafters would have to be cut down so thin it would be the weak point of your roof. I would take your fascia off and cut the siding off 12 inches or so down from under fascia and add another 2x12 outside of your post below it so the top of new rafters would line up to the old roof ( be sure to add room to slip the new metal roof under the old or if asphalt, the osb matches exactly at the old roof osb.. keep in mind - you have 2 truss carriers to your old roof, i would use simpson lags screws (kind for ledger support) and screw the new 2x12 to the post since you will only have one for new roof and there would be no birdmouth on new rafters. for each new rafter it would be tied to the new 2x12 below it and nailed to each old rafter at the top.

 

[EddieWalker]

HOLD ON!!!! Do not notch your new rafters or try to put them on top of your existing beams. The notch will ruin all integrity in the rafter!!!!!


Remove the fascia board. Attach a ledger board to the outside wall of your building so it's tight under your existing rafters. Bolts are always the best for attaching a ledger board, but the new style of lag bolts are pretty good too. Just be sure you get the ones rated for a structural load. They are also called structural screws. Be sure that the word "structural" is on there!!! Some of them are just fancy, extra long screws that do not have any load rating. This will be the support to carry the weight of your new rafters.

Then attach your rafters to the side of your existing rafters with the weight of the new rafter resting on the ledger board. To secure the rafter to the ledger board, use metal brackets with proper fasteners. Simpson has several to chose from. The nails they sell work, but can be a pain to install. They have structural screws that cost more, but are real easy to install.

 

[KennyG]

Not wanting to start a fight, but I'm going to question Eddie on this one (always a dangerous move). Rafters are most stressed in middle where the bending loads are greatest. At the ends the load is purely compression where wood, like most materials is very strong. We notch rafters all the time on the bottom end (birds mouth). If I were doing this I would go the ledger board approach but I wouldn't object to notching the rafter if someone wanted to go that way (within reason of course).

 

[buckeyefarmer]

See post 5