Abstract: A radius member adapted to be connected to the corners of a swimming pool at the intersections of adjacent sidewalls, and having a flexible radius strip extending in a concave arc in said corners, the opposite edges of the radius strip engaging said sidewalls substantially tangentially so that a thin waterproof lining for the swimming pool may be disposed against said sidewalls and the arcuate inner surface provided by the radius strip and thereby minimize the possibility of damage to said lining at the corners of the pool. Several embodiments of means to connect the radius strip to the corners of the pool are included herein, one of these being of a relatively permanent nature and another being readily detachable from the pool.