The system for installing shower walls includes a pressure transfer member for urging a shower wall against a back up support during bonding of the shower wall to the support. An adjustable force development device engages the pressure transfer member to force the pressure transfer member against the shower wall. A support member engages the pressure transfer member when the force development device exerts a predetermined force against the shower wall. A fixation device holds the support member to maintain the pressure transfer position of the pressure transfer member. The fixation device includes a cam that moves a shower wall into a tight corner fit with an adjacent shower wall.