Why do you say building on a slab is more ecological than starting with a basement?
I watched a presentation by Emmanuel Cosgrove of Ecohome who said that a house built on an insulated slab floor was much more ecological and more affordable than a basement. How does he arrive at this conclusion? Basement or not, you need a mechanical room, storage space, a laundry room, cold storage, etc. The way I see it is to build without basement is to decide to build bigger, meaning more materials, more external walls to heat, and a bigger ecological footprint. Please explain, thanks.
Your question raises pertinent points. Basements are certainly useful, but from an environmental point of view, the benefits of slab-on-grade construction over a basement are undeniable, you can read all the pros and cons here -
Slab on Grade or Foundation and Basement; Which is Best?
And have a look at the Edelweiss House that we built a few years ago, it is a 4 bedroom home (or three and storage room).