Home builders began to use asbestos roof tiles at the beginning of the 20th century, following Ludwig Hatschek's invention of the manufacturing process in 1900. Because the asbestos tiles were lightweight and fireproof, their use became popular. As manufacturing technology improved, companies began to produce tiles in different patterns and shapes, enhancing their aesthetic appeal. Asbestos has come under scrutiny in the past 30 years due to its potential environmental hazard. It should be noted, however, that asbestos roof tiles are only a hazard when they are break or crumble and emit dust particles.
Flat tiles, often labelled American, are laid horizontal to the roof's top and lower edge. The tile pattern is created by placing tiles, going from the bottom of the roof to the top, in staggered rows. The presence of overlap on the top and lower edges of the installed tiles is an identification mark.
The side-lap style is also referred to as Dutch Lap. Starting on the roof's lower corner, each tile is laid over an adjacent side. This process is repeated horizontally. The second row is done similarly, but it also covers a portion of the lower row, as with the flat style. Identify this type of tile by noting the side-lap in addition to the flat style, bottom to top, overlay.
The diamond style is also known as hexagonal, honeycomb or French. For this type, each tile is rotated 90 degrees, resembling the shape of a diamond. This process also starts from the bottom of the roof. The two downward facing sides of each tile overlap the two tiles directly below it, and the overlay is repeated upwards.