It was a bug to raise all at once.
that said, the biggest project I have is just my farm, which is high enough to keep furlings at bay, about 5 clicks x enough space to grow 50 barley.
my home is lofted, but only in a giant O shape: the hollowed out center is a usable basement.

To get rocks for large projects, like lofting a 3-4 story 15x15 or so castle, find some plains with those big rock columns. Make a portal, bust the base, pick up the rocks, go make some stuff, repeat. There is no shortage of those columns.