Exterior foam with stone and 10 mm rainscreen
I am planning to build a new house and I have a couple of questions.
The house will be in climate zone 2 – hot-humid (near Houston, TX). The walls will be 2×6 with 3.5″ of open cell spray foam. The walls will be sheathed with OSB and we are planning to add 0.75″ of foam board (R4) on the exterior and use Tyvek drainwrap and a 10 mm rainscreen (i.e. MTI Surecavity).
Some of the walls will have a full stone veneer (3″-5″ bed). Some will be half stone and half Hardie and some will be all Hardie. My questions are:
1. Should the walls be constructed: OSB -> Tyvek -> Foam -> Surecavity -> Stone or OSB -> Foam -> Tyvek -> Surecavity -> Stone?
2. How much space is needed between the stone and the Surecavity?
3. Is a metal flashing needed on the full siding wall that will protect the foam at the bottom of the wall?
4. For the siding, I planned to use during strips to attach the siding to the wall. Where the wall transitions from siding to stone, how would the transition be made from turning strips to Surecavity?