Stair tread

A stair tread is the horizontal surface you step on. Technically, tread depth, also called the going, is measured horizontally from the front edge of one step to the front edge of the next. The front edge that projects beyond the riser is called the nosing.

What makes a good tread

A tread should be deep enough for the whole foot to land comfortably; too shallow and coming down becomes dangerous, too deep and the stride is broken. Tread depth is therefore set together with riser height, using the stride rule. As with risers, every tread in a flight must be the same depth. On winders and spiral stairs, treads become triangular or tapered; the depth is measured along the walking line, and a usable depth is kept at the narrow end. Finishes need to be slip-resistant, all the more so on outdoor stairs that get wet. An anti-slip strip or a contrasting band along the nosing helps everyone, and especially people with low vision, to see where each step ends.

Materials and visualization

Timber, marble, granite, concrete or steel treads change the whole character of a stair. In a render, slight wear on the walking surface, the grain direction of the wood or the veining of stone is what makes a stair feel real. A small bevel on each nosing catches the light and makes every step stand out.