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Adding LVL for joist bearing because joists are too short
4

Adding LVL for joist bearing because joists are too short

Adding LVL for joist bearing because joists are too short

(OP)
Good Morning Everyone,

Hope you all had a good weekend.
Have an issue on a jobsite where for whatever reason the floor manufacturer has produced joists that are too short. To reorder new joists would require an extensive amount of rework, so I was wondering if the below is an acceptable repair? Idea is to bolt a LVL to the rim board to provide the required bearing over the foundation, and attach the joists on hangers to the rim board.
This repair detail is for a typical residential house with I joists.
Any further suggestions ? Much appreciated.

Thanks!


RE: Adding LVL for joist bearing because joists are too short

In your detail, you show the rim and LVL, but no sheathing. What is the floor sheathing attaching to, is it continuous overtop the LVL and extending to a plate on the upper section of foundation wall at the left of the detail, or does the sheathing stop at the step in the foundation wall? Bracing the LVL will be important to prevent rollover, and that might be difficult if the sheathing does not continue to a sill on the left of the foundation wall.

What's the base of the stem wall look like? Is it possible to build a pony wall inside the stem wall and tie it back into the concrete? Obviously you would need to check the stem wall for the offset load, but that might be the easiest option if it all works out on paper.

RE: Adding LVL for joist bearing because joists are too short

It doesn't look good to me. The eccentricity will result in tension on the connection at the bottom of the joist and I'm guessing the hanger isn't rated for that. I think you would be better off bolting a ledger onto the concrete foundation wall below. If you can make it work with 3x or 4x material that is one option, but if you need more length you may need to consider something like a steel angle.

Although now that I think about it, I suppose this isn't that different from a standard ledger connection. Instead of bolting directly to concrete or CMU you are just bolting to wood. Still, it seems like the LVL will have more freedom to rotate than a wall member would, so maybe that is the difference. What about filling the ledge void with concrete tied into the wall with drill/epoxy and then using a standard ledger detail? Not saying it's 100% necessary but I think I'd feel more comfortable with that repair.

RE: Adding LVL for joist bearing because joists are too short

I don't like that detail due to the eccentricity. I've had this issue occur on jobs before and the solution was usually one of:
  1. Get new I-Joists of the correct length or use different joist material (if possible) of the correct length. This is the best solution but obviously not great in terms of construction schedule.
  2. Support the joists with a new load bearing wall framed against the concrete wall and supporting the bottom of the joists.
  3. Sister LVL pieces to each side of the I-joists to gain the additional length needed.
  4. In keeping with your current detail, I don't hate the idea of adding PT 2x framing directly against the concrete wall to support the rim board. The PT would be fastened to the wall and possibly bearing on the floor slab below.
What is the framing condition at the other end of the I-joist? Is it also supported by a similar shelf in the concrete wall? What are the overall plan dimensions where this problem occurs?

RE: Adding LVL for joist bearing because joists are too short

You can run a strap under the beam (and up the backside) and attach them to the bottom of the bottom joist flange to resolve the eccentricity. Not great though

RE: Adding LVL for joist bearing because joists are too short

I don't like the detail, but I believe it would be made to work; it's not just a simple shear connection, you have torsion due to eccentricity to consider in the supporting members as well as the connection between the supporting members. I would much prefer a ledger, however you state "reverse veneer" which to be honest I had to google, because of this, I'm not sure a ledger could be easily utilized. Have you considered combining the rimboard and LVL to be a wider single member? This would still be eccentric to the wall with some checks required, but you at least get rid of some connection issues.

Hopefully you are being justly compensated for this construction mistake.

RE: Adding LVL for joist bearing because joists are too short

3
If I was in the homeowner's shoes, I wouldn't accept anything less than replacement. Homeowners shouldn't have to accept repair details like this for new construction.

RE: Adding LVL for joist bearing because joists are too short

Quote (bones206)

Homeowners shouldn't have to accept repair details like this for new construction.
This is probably the best answer. The owner should at least be informed that the floor of their brand new house will require some band-aids to make it work with the current materials. I wouldn't be happy if this was my place, and I was paying whatever the likely insane construction cost happens to be here.

RE: Adding LVL for joist bearing because joists are too short

Agreed with the general sentiment in here that the eccentricity on this detail makes it unpleasant to conceive in wood

Double agreed with Bones that this is crap that shouldn't be accepted
My rule of thumb is that a homeowner should only be offered a patch job to save the contractor's ass if that patch job actually gives a better performance than was originally specified
In this case, the patch will be significantly worse so it's hardly fair

RE: Adding LVL for joist bearing because joists are too short

Pack the whole gap solid with lumber and anchor into the stem wall to resolve the eccentricity.

RE: Adding LVL for joist bearing because joists are too short

I'm with everyone who thinks this is a bad idea. The house will hopefully be there 50+ years. I-joists are readily available. Why not take a couple of days and do it right?

ChorasDen had a good suggestion - Adding a stud wall below. If they plan to finish the basement at some point they'll be doing that anyway.

If you contact the I-joist manufacturer they have engineers on staff that can deal with issues with their product.

RE: Adding LVL for joist bearing because joists are too short

Bad detail. Joist boots aren't intended to reach out like that.

RE: Adding LVL for joist bearing because joists are too short

I assume a stud wall isn't in the cards because otherwise that would have solved the issue right then and there. How about a bulkhead? You can make it even larger than necessary to allow for your mechanical runs and sell it as a feature. Header across any openings (e.g. windows).

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