2×6 stem wall detail options
I’m in the early stages of designing my future home and ran into a situation where I’m looking for some input. I’m wondering what the best option for me would be at the intersection of the radiant floor slab, foundation stem wall and 2×6 exterior wall. I’ve attached the 3 options I’m considering.
Option A is what I had originally envisioned. I work in commercial construction, and this is close to what I’ve done on previous projects, such as a hangar I just built. But that hangar didn’t have hydronic heating in the slab and was only meant to be kept at about 55 degrees in winter for storage. So then that got me thinking that since this is a residence where I will be heating into the upper 60’s during the winter I may want to revisit this detail. After doing some research i started to be a little concerned about heat loss at the 12 inches of concrete stem wall. That’s where I came up with Options B & C. I like Option B because I don’t need to change any detailing on the exterior, but I have some concern’s whether the engineer will go for overhanging the 2×6 wall 1.5″ with it only sitting on a 4″ stem wall. Option C sounds better structurally in my opinion and it leaves me the option of continuing the 2″ XPS all the way up the exterior if I can find it in my budget, but I have major concerns on how to cover up this exterior insulation and protect it from damage and also make it look decent.
And for reference, this house has a garage and some living space on the slab level with the majority of the living space on the second floor. And I’m located in Maine, zone 6.
I’m wondering if my concern about heat loss in this area is valid or a none issue, and maybe the overhang in Option B is possible, I’ve just never seen it done before. Any help is appreciated, thanks!