The extended cantilever deck process also allows freeform pools to use an undertrack installation with track channel. With this technique, the tracks are laid out parallel to each other at the widest part of the pool on the first deck. A second deck is built slightly raised to allow the cover to open and close without obstruction, and it mirrors the shape of the pool.
For thin deck material such as slate, artificial rock, or tile, track channel and undertrack should be used. This allows for any coping with a thickness less than two inches to safely accommodate an automatic pool cover system.