1. A tape rule assembly, comprising: a housing that includes a reel and a coil spring that provides a rotation bias to the reel; a pliable primary rule that extends from the housing and retracts into the housing by rolling around the reel and that includes a leading edge, a trailing edge coupled to the reel, and two side long edges; a hook that is coupled to the leading edge of the primary rule; and a stiffening member that is a secondary rule and includes a second leading edge, a second trailing edge, and two second side long edges and that includes a fastener that slidably affixes the stiffening member to the primary rule that affects the stiffness of the primary rule in one of two modes: an engaged mode where the stiffening member extends and retracts from the housing with the primary rule and increases the stiffness of the primary rule, and a disengaged mode where the stiffening member is substantially contained within the housing and does not substantially affect the stiffness of the primary rule.