I wrote about Porcellio spinicornis, an isopod I photographed and collected in my sister's backyard in Montreal last month. S.P. Hatchett (Biology of the Isopoda of Michigan. Ecologocal Monographs, 17: 48-79, 1947.) gave some rather unusual habitats where he had collected this species in Michigan:
P. spinicornis has been collected in places usually not considered desirable situations for isopods. It has been taken in the attics of two abandoned farm houses...[it] was once taken from a concrete window sill on the third story of the Natural Science Building on the campus of the University of Michigan. It has also been collected along the walls of basements and in a store in Ann Arbor.
He ties the occurrence of P. spinicornis on building walls to the preference of the animal for habitats high in calcium carbonate.