Afternoon! I've read as many of the let in ledger info threads that I can find here and elsewhere and wondered if you all can help a bit. I have a 60x36' building with 16' walls (2x6, 24"oc), trussed roof, concrete foundation,etc. basically an empty box. I have been asked to help with the construction of interior living space that is scheduled to include a partial second floor. Since this seems to be a form of balloon framing, From what I gather, letting in the ledger on the outside walls would best a best practice in this case, but I'm wondering if i could actually let in the 11-7/8" tall end board for the i joists and use hangers? Seems like a lot to let in but I am trying to avoid having 24"oc for the joists. I would like to have the 16" oc and not have joists in the center of two studs. The max span will be 14' and terminate at an interior wall. According to the i joist manufacturer 14' with 24" oc is acceptable, but I would rather stay 16" on if possible. Maybe I should also ask for thoughts on the 24" oc joists? Will they be bouncy at 14' (TJI320 looked to be the min), 25/32" glued and nailed decking and 1/2 sheet rock below. Upper areas will be typical living space(bedrooms, media room, small bathroom). I'd rather not have a bouncy floor and the budget is there. Thank you in advance for the input.
Andrew
Hey Andrew,
The complete detail for that prescriptive assembly calls for the joists to rest on and cross over a let in ribbon. The joist run beside and are fastened to the studs. (That puts you at 2' spacing. If the joists can handle it, which they can the way to kill bounce is with a stiffer subfloor/ floor.) Hangers on the ribbon do not provide a withdrawal tie, they don't "lock" across the building. I'm sure there are ways with enough simpsonizing.
But, that is a prescriptive detail for sawn lumber. Your I joists are an engineered product. Their details rule. The connection I just described is outside of anything I've seen in prescriptive I joist details. Since they are an engineered product they have awesome free support. I'd talk to the I joist supplier and let them give you a design for that connection.
Thank you don. I appreciate the input and it makes sense. I Have a feeling we might be using conventional lumber, but I will be talking to the supplier tomorrow. Again, I appreciate it!
Andrew
I like 16" centers for joists, you can't have a solid enough floor in my opinion....have you considered just adding 2x4 walls under the joist ends on the exterior wall? Might give you more options.... I always try to err on the side of beef, adding to the structure when possible rather than taking away from it....
Quote from: akwoodchuck on August 28, 2018, 11:28:02 AM
I like 16" centers for joists, you can't have a solid enough floor in my opinion....have you considered just adding 2x4 walls under the joist ends on the exterior wall? Might give you more options.... I always try to err on the side of beef, adding to the structure when possible rather than taking away from it....
I have considered doing that. It's definately more work, but may be worth it. Opens up options no doubt.
Thank you!
Andrew
Okay. Things are going to get started soon. I have determined that for me to be happy with the end product of this build, I want the upper floor to be 16" on center. Since the walls are 24" oc there will be two "floating" floor joist ends for every 4' of wall. I know I need to add a ledger into the wall studs but the two floating joists in those 4' is giving me some trouble. My latest thought is this. Build a 2x12 ledger that is let in to the wall studs by 3/4" but also dado the back of the ledger to fit into the stud so it is flush. Then at my 16" centers, cut a 5.5" by 1.5 "pocket" in the ledger and a matching pocket at the wall end of the joist. A saddle joint of sorts. This would "Lincoln log" the joist to the ledger. I know I will be removing quite a bit of material from both the ledger and joist, but would plan on also using a joist hanger. My thinking is that this would give me horizontal support "withdrawal tie" for the exterior walls as well as the vertical support for the joists so they don't roll over. I'm also thinking that if the joinery is done correctly the ledger would pinch the joist under load. This is really only for the floating joists Every 4' there will be a joist attached directly to the outside wall stud and over any windows there will be additional support from the headers. I'm trying to avoid an additional 2x4 wall on the outer walls, but really would rather have the 16 of for the joists. Am I making sense? Am I out of my mind with this idea? d* thanks again.
Andrew
I see the building width is listed in the OP as 36 feet. It is not clear to me if the plan isto use 2x sawn lumberjoists or some sort of manufactured joist. Can you clarify what the joists are to be?
Also, not clear, has the building been constructed, the walls up or not yet? Still in design and plan stage?
Don. Thank you. Building itself has been completed and standing for a couple of years. That is part of the issue. I was not a part of the original construction of said building, but have all of the original "drawings". I am planning on 2x lumber at this point. I think in this situation, it might be a bit more logical.
I might add...maximum clear span for any joists will be 14'. Not trying to clear all 36'. There will be bearing walls. Double top plates on the interior walls. Planning on all headers being 2x12 lumber, except for a few windows that are not applicable. There will be a few hallways and a staircase. Should be plenty of support on the interior.
Just trying to do the best I can tying in the joists to the outside walls and get the 16" oc.
Andrew
Don't notch joist or ledger. You do need to block or restrain both ends of each joist to prevent roll. If this is to be inspected run it by the building dept and be prepared for a little engineering... which is where this question should go anyway.
Quote from: Aspoonhour on August 28, 2018, 10:47:33 AM
Thank you don. I appreciate the input and it makes sense. I Have a feeling we might be using conventional lumber, but I will be talking to the supplier tomorrow. Again, I appreciate it!
Andrew
What was their solution?