My workshop is a converted barn with corrugated fibre cement sheeting roof. It's been sprayed with expanding foam and when they did it they assured me that they'd sealed the apex where there is a 'top hat' shape.
Well they obviously didn't - I recently had an enormous bonfire ( 1/2 mile of Leydandii hedge top and there is a line of 'fall out' ash down the length of the workshop. So if the ash blew in then my heat MUST be able to go out !
No chance of getting them back, as access is now very difficult with all the machines in place, and I don't want them covered in foam anyway !
SO - my thought was some form of insulating sausage that I can poke up there with a long stick - if there was such a thing as a 6" diameter cylindrical shape I reckon it would stay in place by friction.
??? BUT YOU MAY HAVE OTHER SUGGESTIONS PERHAPS ???
Andrew