We bought a house two years ago that sits on a shallow stone foundation with vented crawlspace, which until recently was only 0-12 inches deep. It has all the problems you’d expect from this setup–cold floors, musty smell, easy access for critters, rotted sills, etc. We had it vacuum excavated a couple of feet in order to gain access for installing vapor barrier on the ground and insulation between floor joist. After getting a couple quotes for replacing the sills and shoring up the stone foundation, we decided that after all that expense and trouble, all we’d gain would be new sills and a repointed shallow stone foundation. So we made the decision to get a new foundation installed (at even much greater expense and trouble). But the end product is a far superior long-term solution, which is important because we plan on staying here for a while, and eventually making significant improvements to the above-grade part. I read somewhere that a foundation is a somewhat important part of a building…

So now we’re awaiting initial engineering plans, and I wanted to make sure we take into consideration important features to have, in particular from a comfort and energy usage standpoint. I have this so far: Drainage system
Rough plumbing for future bathroom
Window placement including several egress windows
R-20 on exterior walls (probably use rockwool)
R-10 under slab –is this really necessary?
A capillary break/sill seal product –any recommendations?

The house is located in Massachusetts and the crawlspace is very dry, so hopefully that bodes well for a basement. Any other features or construction details that need to be taken into consideration–things that we better do now or else will be very difficult to add in the future?
Any advice appreciated.
Thank you,
Steve