How close to the old foundation do we want the new foundation?

How thick do we want the outside walls to be?

• Net Zero standards in Oregon say roofs should be R60 and…
• walls should be R-21 cavity insulation + R-5 to R-15 continuous exterior insulation OR…
• deep-wall assemblies like 2×8 framing packed with cellulose plus exterior rigid foam.
• Zip R sheathing has 1.5“ of exterior insulation and is R6. Works.
• Rockwool is about R4/inch, they sell an R23 version for 6” (5.5“) walls and an R30 version for 8” (7.25“) walls. Which do we want? Pretty easy to use doubled 2x4s with a small gap to get that thicker version. Basically the same cost as 2×6 walls, and will provide more sound isolation.

How tall are the floor trusses going to be?