Loose stair carpet can sometimes be repaired simply by refitting the carpet back onto the carpet gripper underneath. In other cases we may need to lift and refit the carpet completely in order to leave the stair carpet repair in a safe condition.
Individual treads that have become worn can also be replaced without having to replace the carpet on the entire flight of stairs, thereby extending the life of the carpet. Repairing stair carpets in this way does require you to have some spare carpet for me to use for the repair.