(pronounced TRED)
Besides being the integral word in one of the USA’s most famous historical phrases, as well as one of the methods investigators on “Forensic Files” use to identify criminals (shoe and tire treads are like fingerprints!), a tread is a very important design term. The tread is the portion of a stair that you step on – i.e., the flat, horizontal part. When treads are too shallow or too deep, they are difficult to navigate and become hazardous, as they don’t align with a human’s natural stride; therefore, local codes govern tread depth and design for all types of stairs. You will encounter stair treads made of wood, stone, concrete, rubber, vinyl, metal, fiberglass, and glass, and they can be smooth, textured (preventing slipping), perforated (draining water), heated (dissipating ice), worn (in historical structures), and even illuminated (as in movie theaters and exterior landscapes). Guess this gives new meaning to the term “tread lightly”…