The flaw to this approach in the joist to beam/sill plate attachment is that you only get part of the joists' strength since the bottom portion of the floor joist is not supported. You can't count the unsupported 2", of floor joist and nailing the bottom of the joist into sill plate does not count as support. You need to set it on a ledger board or use a joist hanger. For example, if the joist is a 2x10 and the bottom most notch is at 7-1/4" (typical 9-1/4" minus the unsupported 2"), then the joist is only as good as a rough 2x8 and you have lost 2" of support across the height of the joist. Why is this important, because the standard span tables are based off of the supported portion and they assume the joist is fully supported and not just with nails. There is no real shear support from a nail or ten nails toenailed in. Plus there is a minimum amount of distance alog the joist that needs support at the end member, also in the span table. So if you wanted a tile floor supported to L/400 or better and the joist span called for a 2x10, you wouldn't be there with this approach since you are only supporting a 2x8 worth's of joist.
Without installing hangers on the lower portion of the joists they still don't have the full structural strength of the full depth of the floor joist. You basically only have what depth there is currently for the notch. What hangs below unsupported is worth nothing. Just a matter of time before the joists split at the notch.
@@EdwardT9 The existing joists are still supporting the house. It would be too expensive to do the additional supports for the house as well as having to install a higher beam or install cripples. Why do all that extra work when you can just install metal hangers full height and achieve the same result.
@@gary24752 yes, I agree. I hadn’t factored in needing to support all the joists at once in order to cut them. Doh! A hanger added now will certainly help as those notches will probably crack and split each joist eventually.
