Fake stone siding in the mid-20th century contained either a mix of shale, water and lime, or materials similar to cement, if not cement itself. The stone-like appearance of the siding came from stone-shaped molds that produced either individual “stones” or larger slabs. The Old-House Journal says the material remained pliable enough during installation that after it was up on the side of the house workers could further mold it and decorate it before adding final finishing and waterproofing layers.
Fake stone siding wasn’t just a hallmark of the 1950s. This Old House notes that in the 1400s a fake marble veneer made from pigmented plaster, called scagliolia, was common in Italy; the 1500s in Venice saw the use of a mix of plaster and marble called Venetian plaster; and in colonial America in the 1700s, wood painted to look like stone was used as siding for buildings. Synthetic stone siding became common in the United States in the late 1920s, and two new variations in the 1950s claimed to have greater durability than the original sidings from the 1920s. The Old-House Journal says one brand received accolades from Georgetown University, calling the siding superior.
Fake stone siding had an advantage in that it was cheaper than real stone or brick and required little maintenance. The siding also prevented moisture from getting inside, which could happen in older brick buildings. The fake stone also allowed those living in earthquake-prone areas to have homes that looked like they were made of rustic stones or ivy-covered bricks without the risk of un-reinforced masonry that could collapse in severe shaking.
The major disadvantage to fake stone siding is it can look awful. The addition of fake stone siding in high-up areas can lend a top-heavy look to the building. It can make a home seem dated, or it can clash with other paint colors or even the style of the building. For example, the Historic Preservation Commission in Excelsior Springs, Missouri, notes that a historic building it has been working to restore was improved “substantially” when a band of pale fake stone siding was removed. The building itself was of the Victorian Commercial style, but the fake stone was added in the 1950s or 1960s, creating a walled-off appearance that left little room for windows. The Old-House Journal says the application techniques for fake stone siding could also create damage to the underlying wood or masonry.