OK. just from what I've seen i can likely provide you with an answer.
You have a massive pit in the middle of your town, it's FULL of items, on top of this theres a HUGE mining area and on top of that, you've got like 600+ wood sitting on the ground next to your houses, on top of this you've got tons and tons of items sitting around from monster drops and you're about 500 items from your towns item limit. Added to all this, you still have scaffolding sitting next to a couple of your houses that should have been removed but it looks like you build the road and the scaffolding got stuck. Plus 31 citizens...
Stonehearth is by no means optimized, and i'm guessing by the time you reach this point your system starts to die under the pressure of trying to move over a thousand items at once, WHILE trying to mine more and still trying to get the pathfind to your loot drops from enemies. ON top of it all, the lua pathfinder is working hard to figure out how to finish your buildings by removing the lasts bits of scaffold so it can stop checking them.
Stonehearth unfortunately can't do that much at once without a really strong computer. (yet) Also it really dislikes large mining areas and the devs suggest you break such areas up a bit so your little people and mainly your computer don't get overwhelmed.