Insulbrick. Insulbrick or Inselbrick (the product tradename) is an exterior siding product that mimics brick. The owners of the church building in this picture, located in the 900 block of Shelby Street, probably applied their insulbrick siding in the 1930s or 1940s, not long after the asphalt and fiber siding came on the market. Mass produced and inexpensive, insulbrick came in a variety of brick-like colors and was touted as an insulating material—the product name was a no-brainer.
Advertisements for Inselbrick appeared regularly in Indianapolis newspapers in the 1940s, proclaiming the new look, end to house painting, and draft elimination that could be achieved by the easy process of nailing on the large sheets of material. Judging by the number of houses we see sporting insulbrick, it sold well.
The original wood siding is visible where the insulbrick has chipped off of this church steeple. Since it was nailed on in large sheets, removing the rest of the insulbrick would be a relatively easy task.