Thank you John for this interesting idea.... the owner of the garage suggested this too.
Thank you everyone who has taken the time to respond....
The stonemason has filled in the majority of gaps in the corrugated walls with expanding foam. The gaps are where the walls met the curved metal roof
I have made sandbags to lay along the bottom of both of our doors and I am now contemplating hanging/making a tarpaulin wall around two sides of the garage to make a sort of "second garage" within the main garage (which is massive)
