Flue blocks are big and heavy as is the flue itself. Our "attic" is cold and there isn't a lot of room between the roof joists. I don't know how but they managed to set those blocks and the flue to within 6 inches of the roof. (You can't see the other person but trust me he is there. ) There is no choice now. To finish placing the other flue blocks they have to get on the roof and drop them in from above.
Today it was still sub-zero and windy again. Not a day to be cutting a hole in the roof and trying to set block. Instead, they finished up the pedestal and the hearth.
It's a beautiful thing.