Formstone was patented by the Baltimore based Lasting Products Company in 1937.
Originally the majority of buildings faced in Formstone were single-family homes. However, it was not long until rowhome homeowners in urban and working-class areas of Baltimore wanted Formstone, since these homes, built by the 1,000s in the early 1900’s, were constructed using low quality bricks, which were porous and leaky.
This single family home is typical of many still seen in Baltimore City and County
These buildings required significant maintenance -- repairing bricks and re-pointing (since the mortar used to lay them was also poor quality). Painting was also used to repair the bricks, but salesmen touted that for the cost of three painting jobs Formstone could be applied to the building’s exterior and eliminate much of the effort to maintain the exterior brick. It was promised to remain weatherproof and insulating forever with no upkeep or repair (which didn’t turn out to always be true).
For this reason, Formstone was primarily used in remodeling, although it was sometimes used for new construction.
Many people don’t realize that Formstone buildings actually have brick under the Formstone facade.
The formstone cladding is chipping away at this building in Highlandtown, revealing the brick underneath
A homeowner holding a picture of his house on S. Bethel St before the Formstone was removed
At the height of its popularity in the 1950s, Formstone was a sign of wealth and stability in the working class neighborhoods of Baltimore. But the longevity of Formstone was not living up to the promises and it fell out of favor by the 1960s. Aluminum and vinyl siding, much cheaper ways to weather-proof buildings, became more popular and contributed to the decline of Formstone.
One major failure of Formstone is that the metal lath holding the faux stone to the building can start to pull away from the brick. Without a strong bond between the Formstone and the underlying brick, moisture is allowed to enter between the two materials and become trapped. Applying Formstone to rowhouses constructed with early brick from the eighteenth and nineteenth centuries caused many problems. This early brick was soft, porous, and susceptible to deterioration. Formstone prevents the historic brick from breathing and the accumulation of moisture causes cracks to form. This moisture combined with the freeze-thaw cycle can damage the Formstone material and, if left uncorrected, can lead to further deterioration and penetration of moisture into the underlying brick. This can lead to loosened mortar joints on the brick facade. Formstone is only waterproof as long as it does not deteriorate and separate from the wall.
Another issue stems from the application of the Formstone. When it was applied to the exterior facade of a building, significant architectural features were often covered up or removed. Features such as cornices, lintels, and sills. These features were not only decorative -- they were necessary for diverting water away from the building, leading to even more damage from moisture intrusion.
There is debate over the historical significance of Formstone. Because it was usually applied to buildings long after their initial construction, Formstone is viewed by some as an inauthentic addition that detracts from the historical significance of the building. But some historic preservationists, particularly in Baltimore City, argue that Formstone has acquired its own historical significance as it has become a part of the Baltimore landscape and is representative of the history and evolution of the city’s working-class neighborhoods. These preservationists want Baltimore to retain it title of the “Epicenter of Formstone.”
Large Formstone building in Curtis Bay
A Formstone clad house on E. Lanvale St