What Are Clinker Bricks?

Did you know that what we now consider as unique and charming clinker bricks were once considered trash by brick manufacturers? In the early 20th century, their irregular shapes and vibrant colors were seen as manufacturing accidents, but creative builders and architects found beauty in their nonconformity.

Clinker bricks, named for the distinctive sound they make when banged together, are the result of being placed too close to the fire during firing. This intense heat, often from coal-burning traditional kilns, caused the bricks to twist into volcanic shapes and textures. The overbaking process produced rich, warm colors ranging from reds, yellows, and oranges to deep browns, purples, and blacks.

While clinker bricks were rejects to brick manufacturers who valued uniformity, they became treasures to early modern architects, builders, and homeowners seeking architectural detail. John Gavin of Gavin Historical Bricks, an Iowa City-based supplier of reclaimed antique paving and building materials, explains that although clinker bricks were discolored or misshapen, they were still a solid building material. In the early 20th century, clinkers gained popularity among avant-garde architects who appreciated their unusual characteristics.

During the Arts & Crafts era, clinkers were used to accentuate bungalow architecture, creating visual interest in focal points such as chimneys, porch supports, and garden walls. Their use spread to other architectural styles, including Colonial Revivals along the East coast, where entire homes, not just chimneys, were made of them. Kingston Heath, director of the historic preservation graduate program at the University of Oregon, suggests that clinkers appealed to Colonial Revival designers because their irregularities hearkened back to pre-industrial times.

So, if your old house is made with these uncommon bricks, knowing their background can be helpful for future restoration or repair projects.

There are several homes in the Wood Streets that have these type of brick.