Need help figuring out barn extension
- Thread starter petebert
- Start date
EddieWalker
Epic Contributor
Simpson has a metal bracket for just about every type of connection, and 100% of the time, using them is better then not using them. I'm not exactly sure what you are asking, but will reply as if you where asking for ideas how to do this. I would attach my rafters to the existing building with joist hangers. I like the screws Simpson sells with the bolt heads on them. I forget the name of them, but they go in quick and easy using my cordless impact driver. Short ones for the hangers, long ones for tying the joist into the header.
On the outside wall, I would have a header on the inside of the wall and rest my joists on top of that. You don't have this in your drawing. Then I would have the end of the joist resting on top of the header on the outside of the wall. Then attach the joists to the headers with hurricane straps, or rafter ties, or whatever you feel will work best for that location.
I would not attach anything into the end grain of a rafter or joist.
On the outside wall, I would have a header on the inside of the wall and rest my joists on top of that. You don't have this in your drawing. Then I would have the end of the joist resting on top of the header on the outside of the wall. Then attach the joists to the headers with hurricane straps, or rafter ties, or whatever you feel will work best for that location.
I would not attach anything into the end grain of a rafter or joist.
I decided against sitting on top of the header due to maximizing space. If I leave the header at the top of the posts and put the rafters on top of that I lose my 3/12 pitch if I want a 14' extension. There will also be a door on the new wall. This will be for livestock who aren't too picky about the opening size but I thought it would be nice to leave options available to me. Right now with an 8' eave and a 12" header I'm down to a 7' opening height and I didn't want to reduce that further.
The simpson screws are called strong ties which I planned on using. On those simpson hangers, so the long screw runs through the diagonal hole on the side? I guess the idea is you're tying joist/hanger/header all together?
What I asked earlier is if there should be a rafter tie, like in this picture to create the strength of a triangle. Just have to ignore half that picture since mine isn't a traditional roof, but a half roof.
The simpson screws are called strong ties which I planned on using. On those simpson hangers, so the long screw runs through the diagonal hole on the side? I guess the idea is you're tying joist/hanger/header all together?
What I asked earlier is if there should be a rafter tie, like in this picture to create the strength of a triangle. Just have to ignore half that picture since mine isn't a traditional roof, but a half roof.
EddieWalker
Epic Contributor
I see what you are saying now. Yes, that would give you more strength. Do you need it is the question. In my opinion, I do not think you do for a lean to that is securly attached to the existing building. I forget what you said you where using for your rafters, but if it was me, I would go with 2x8's or bigger.
I would also suggest you reconsider resting the rafters on top of a header, or a beam. For the walk through door, you can get away with a shorter span, and less wood above it to squeeze in a walk through door as long as the rest of the wall was properly sized. Given the spacing of your rafters, you might not even need a header over your doorway.
How far apart are you spacing your rafters? If at 48 inches, you just need a post under each rafter and the weight of your roof would rest directly on top of the posts. That would be the strongest of all possibilities.
Looking at your drawing, you have a lot of rafters. Are you going to shingle a 3:12 pitch roof or use metal? Shingles should never be used on anything less then 4:12, so metal is a much better choice. If using metal, you can space your rafters out 4 feet and use 2x4's on the flat for your purlins. That makes it really easy to find when screwing in the metal too!!!
I would also suggest you reconsider resting the rafters on top of a header, or a beam. For the walk through door, you can get away with a shorter span, and less wood above it to squeeze in a walk through door as long as the rest of the wall was properly sized. Given the spacing of your rafters, you might not even need a header over your doorway.
How far apart are you spacing your rafters? If at 48 inches, you just need a post under each rafter and the weight of your roof would rest directly on top of the posts. That would be the strongest of all possibilities.
Looking at your drawing, you have a lot of rafters. Are you going to shingle a 3:12 pitch roof or use metal? Shingles should never be used on anything less then 4:12, so metal is a much better choice. If using metal, you can space your rafters out 4 feet and use 2x4's on the flat for your purlins. That makes it really easy to find when screwing in the metal too!!!
And if that were the case, I'd notch it single depth and then double it (same end profile as you have now, but the rafters are 1-1/2" shorter) and use longer nails in your rafter hangers to hit both 2x's...?
Edited to add:
Your other sketch shows girts, so you'd only really need a taller header over the doorway at the last bay?
Edited to add:
Your other sketch shows girts, so you'd only really need a taller header over the doorway at the last bay?
