I’m in the planning/design phase of a remodel project that calls for floor joists installed on an existing 8″ block wall. I plan to use 2 x 10 joists over a 13’6″ span, with the sill plate anchored to CMU webbing. Unfortunately, this may raise the wall height beyond what’s allowed and create other problems due to grade elevations. What I’m wondering is if I can notch the ends of the joists to sit on the sill plate–and if so, how deep the notch can be–so that the framing sits about 6″ above the block instead of 11.” This way I would only need one step to the entry door instead of two. I usually do my own drawings (by hand) for the permit, then get these reviewed by the engineer. But if I ask my engineer, I’m pretty sure I’d have to give him at least $200 for an answer he might not even have. Any thoughts?
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Notching as joist effectively turns the joist into a smaller framing member. You can probably notch and then set the bottom of the joist into a hanger.
Ultimately, the load the the joist is carrying at this point will determine the amount that the joist can be notched. The primary forces at this point is vertical shear. There is no bending forces to be considered.
If I remember correctly, shear value of #2 yellow pine is +/- 1000#/sq.in.
If you have an area of (5"x1.5") 7.5 sq.in x1000 =7500#, is the load that can be supported at that point.
Remember. This information is worth exactly what you have paid for. Contact your friendly local engineer before proceeding.
Notches at the end of floor joists are addressed in the code; 1/4 of the depth of the joist is permitted for sawn lumber.
If that doesn't get you where you need, this would be a perfect application for top-chord bearing open web trusses, which would likely have 3" of material above the sill. If you did this with a double sill plate you'd get your 6" above the block.
Or if trusses aren't an option, you could rip sill plates to match the 8" block and then use top-mount joist hangers to hang the joists flush with the sill plate.
Thanks; I'll look into both options.
Top chord bearing open web trusses sounds like a good solution, and may be the best, but I wanted to use I joists on the part of the floor framing that calls for a cantilevered wall. I'm wondering if TJI's can be ordered or modified to be top bearing. This would save me from having to demo the top course of block, not to mention a lot of expense on hangers. I haven't seen that done, but it seems doable. Of course, what's doable isn't always what can get approved. What do you think?
TJI's definitely cannot be top chord bearing and you cannot remove any top or bottom chord material on them.
And floor trusses can be designed for almost any situation, including cantilevers. An added advantage of using floor trusses is they'll be designed for your particular situation and engineered accordingly.
Thanks for the help. After giving it a little more thought I came to the same conclusion, but it always helps to get a new perspective.