If a stair carpet is to be laid on the steps, there are three installation methods. Step mats in different sizes and shapes can be placed on the treads, a continuous carpet runner can be placed in the middle of the staircase or the stairs can be covered areally.
First Requirement Step Base
If you select a stair carpet, runners, or step mats that have bends at right angles over the tread edges, always get a sample. Bend it around an edge for later installation and check for expansion of the pile. It should not allow for a look at the pile roots or the underlay of the carpet.