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I am planning a 16’x27′ single story addition off of the back of my house. I plan on using I-Beams that will run the 16′ length. They will run parallel with my existing floor joists which are 2×8’s. My question is will it be strong enough to add a second ledger board off of the existing one and hang the I-Beams with joist hangers? There is no other load on the ledger except the weight of the floor. The new roof will be a shed style and will run from the existing second floor wall to the new wall 16′ out. Would it be better to install some piers and place a beam under the new ledger?
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I hate to answer a question with questions but.....
Are you meaning that you intend to use I-joist (wooden I-beams)?
Why do you need to add another ledger plate?
Now, to answer what I think you've asked:
I assume you are adding the ledger to add strength to the existing for use as a beam. Then you want to hang I-joists from that. I do not know if joist hangers are appropriate for I-joists. I've only seen them where they have been installed sitting on top of a sill plate or beam. Because of their shape, I would be hesitant to use joist hangers on them unless there are hangers specifically designed for this.
another thing, you are going to need to calculate whether or not the ledger, converted to a beam, will support the weight of both floor systems. How much of a span are you going to have? are you adding a full basement beneath the addition?
If there will only be a small (under 3')entrance between existing basement and new, then you should be ok in usung the ledger for conversion to a beam. In this case, you may want to remove the ledger (existing) and just run your I-joists through the openings and on top of the sill plate. This way you will have a better support. Just set your I-joists off to one side of the existing floor joists if they run parralel to the I-joists. If they run perpendicular, then you could run past the sill plate to the first joist and tie in there.
Pete
*Kevin, I've hung tji's with hangers several times, if you can, just use your existing ledgers. Squirt a little glue on the hanger before setting the tji in them.simpson strongtie
*When I see "glue" I think Elmers or Tightbond.Maybe a bead of construction adhesive, instead?Hangers are quite common w TJI's, and JimL's advice is spot on...use the adhesive or you may suffer a squeak or two.
*Maybe this goes w/o saying, but make sure to get the hanger sized for the beam and load. The I-joist supplier should be able to tell you which of the many Simpson hangers to use. The one's in stock at HD may not be right for this job.
*Thank you for taking time to answer my question. I should have specified that the existing house ledger and floor joists are 2x8s.(I think the original builder skimped where he could 28 years ago) The reason I thought of adding a new ledger was to fully support the new 9 1/2" I-joists. The new joists must be that size to span the 16'. So my concern was that this may be too much load for a 2x8 ledger. I have to already offset the height of the new foundation to get the floors to match up. The span is going to be over a four block crawl space. The existing ledger is sitting on the wall of a full basement. I think that after reading the responses that it might be best to put in peirs and a beam for extra support. Please e-mail me back if this information changes your opinion of the project.
*Kevin, could you bolt (bolts and nuts, not lag bolts) another 2x8 ledger to your existing, then you would be able to nail the hanger flanges that overhang the top of the ledger. Will the extra 1 1/2" allow the joists to clear your existing foundation wall? View Image
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I am planning a 16'x27' single story addition off of the back of my house. I plan on using I-Beams that will run the 16' length. They will run parallel with my existing floor joists which are 2x8's. My question is will it be strong enough to add a second ledger board off of the existing one and hang the I-Beams with joist hangers? There is no other load on the ledger except the weight of the floor. The new roof will be a shed style and will run from the existing second floor wall to the new wall 16' out. Would it be better to install some piers and place a beam under the new ledger?