I would like to build a home utilizing SIPs, and I've run across some information I don't fully grok.

My understanding is that balloon framing generally means that a 2 by is inset inside a panel, and then joists are hung using a face mounted hanger, with the subfloor completely enclosed by the SIP envelope. On the other hand platform framing has the subfloor extending out to the exterior of a SIP wall, and the joists are supported by a top mounted hanger.

Balloon framing sounds like it would minimize a thermal interface, however I've run across a statement that platform framing ties the building together axially. i presume this axial loading is from the roof down through the walls. Does the subfloor provide much support in this? I could envision ties from joist to joist, but I have a hard time visualizing OSB making a difference.

Or is this talking about the joists themselves? In which case wouldn't something like a Simpson IUS hanger take care of this?

https://www.strongtie.com/facemounthangersijoist_ijoistconnectors/ius-miu_productgroup_wcc/p/ius.miu

Wouldn't you be able to route a small channel above a 2 by at each joist location for the insertion of these hangers? Or would this compromise the structural integrity too much?

On platform framing, how do you protect the OSB edge exposed to rain? Is this taped over and then covered again with a WRB?

Not sure about the terminology but making any kind of modification to the SIP panel (either as in inset or a channel) may weaken it structurally. If the goal is to keep the floor joist inside the SIP envelope then I think there are two basic approaches.

The first would be to use Simpson HB type hangers that would hang from the SIP top plate. The sub floor extends over the top plates, thus tying everything together and the load being carried be the SIP wall. I can't envision where you are concerned about an exposed OSB edge.

If you are using jumbo SIPS that would not have a top plate for the floor to bear on, then you would need to install a ledger to the SIP and the appropriate hanger in which your IUS type might work .

Most any approach that is not detailed by your SIP manufacturer will probably need to be signed off by a structural engineer.

balloon framing on a permatherm panel hanging rim track