I really like the WWII range for my 15mm wargaming, and I’ve bought and printed several of them. The most useful piece (so far) is the French Townhouse.
In one of the rule sets we use (Chain of Command) buildings exist in one of three states: undamaged, unstable, and fallen down. I remixed the Townhouse roof to include some minor damage, to indicate a building that is usable but unstable, so that I don’t have to print a whole new “ruined” building to replace an undamaged one on the table. It’s a quick fix, but it should do the job.
It occurred to me that this sort of thing might make a useful “add-on” file to go with your existing models, to extend their usefulness for another couple of bucks. Is this the sort of thing you might consider making?