[once_inc]

I've recently been looking into the natron theory, which I also like. Instead of chiselling out big granite blocks and moving them long distances, you use a bucket of powder and a lot of wood ash to chemically form rocks.

[saalweachter]

What do the energy and material requirements look like? How much heat, how much wood, how much natron?

[dredmorbius]

Wood, in an environment in which trees were exceptionally scarce and high-value assets.