If I go with baloon construction on my small shed / cabana, is there any reason I can't go with joist hangers since I am only going to have 2 x 4 stud walls and don't want to notch them?
Sorry, don't think I made it clear. The joist hangers would be for the joists forming the loft floor.
Do they make them to do that?
The ones I've used fasten to a flat surface, not around an edge.
Flat plates coming out from the sides, some little right angle job (that might have to be routed in for drywall clearance) on the bottom sounds like too much trouble.
Same comment on using triple 2x4's for the studs so you could use a standard joist hanger.
I don't know if it is OK, but Hal said he attached a ledger with lag screws. Then you wouldn't be cutting the 2x4. (Understand I have 0 experience - I'm just tossing out ideas).
The question is, after that what do you do with the wall/ledger/floor joist intersection after you've done that. There probably is some really creative, gorgeous solution.
(and a few minor issues like fire blocking--but see PEG's pictures for that)
You can attach a ledger to the studs with lag screws and then hang the joists from this. By not notching the studs you are bearing all the weight of the loft on the shear value of the lag screws. Make sure you are safe as a failure can be dramatic! :-[
a 1/2" dia. lag screw can support about 470 lbs in shear. From JLC, 12/94 p 66. A couple of lags per stud (assuming 24" o/c) could support 400 lbs per foot of loft length or about 10' of loft width. If the loft is less than 20' wide you should be OK.
Use a nice fat washer on tight lags so you spread out the bearing and don't split the ledger.
Another way, since you are balloon framing, is to extend the joist into the wall cavity and attach the joist directly to the stud. You lag, nail, or screw the joist directy to the stud ... and a short cripple post (2 x4) can be added against the stud for additional support under the joist.
Of couse, this plan offsets the joist centerline to the stud centerline and has to be accounted for when flooring ... or sheathing.