I think initially the roof took the weight and then collapsed after a 'successful' emergency landing.
It does seem particularly unfortunate that if the aircraft was out of control it crashed onto a single storey, flat-roofed building (although Glasgow does abound with pubs of this construction). Does seem to suggest that it might well have been a last minute choice for an emergency landing. But, like a lot of those spouting on tv, what the hell do I know?