Hmm, considering the scale we're talking here, making it multipart would be impossible. I mean, the roof is about 1mm high, just take a file or knife, do a single smooth move and the roof is gone.
However, I could also simply remove the whole roof in its entirely, just have a flat generic one, it does mean that you'd need to add them all individually. That would be a lot of sculpting/scratchbuilding.