Clay tile and slate is commonly chosen for its appearance. Tile is often chosen for the ability to provide homes with a southwestern, Italian or Spanish Mission look, and slate is often seen on more upscale homes.
They are natural substances that won't burn or be as affected by the elements or insects as would organic material. However, they are extremely heavy and cause significant stress on your home's structure. This puts your home at risk in the event of seismic activity or weakness caused by fire. Installing clay tile or slate on an average home can be very expensive due to the complicated nature of the installation and the cost of the material itself.
One common finding when installing clay tile or slate is that extra roof support systems are needed due to the extremely high weight of these materials.