Yea the Dwarves quick rebuild of World Knot shows they all have the building knack. The spacial (yes spacial ot a misspelt special) seem easy to the Dwarves, and since the Worldknots need only to be powerd from one end to work all it's need is a Dwarf to power it on the other side.
On the Roofed Stonehiem, I always thought that was a roof. I thought it meant fallen city/not fallen city like the ruined house/standing house for Province cities.