Opening a can of sardines

Or raising the roof? We are having an extension at college. We can't build outwards because there is no room, so the only way is up. (One might think we are going down too, judging by the excavations going on for the new bit.) Today part of the roof is coming off, ready for the next storey. The other new bit is going over the yard, on some sort of stilts, hence the drilling down.