DIY Doorless Shower Pan

Check that the floor is level where the shower pan will go with a carpenter's level. Add wood shims to the flooring where the floor drops below a level grade. Remove any nails or obstructions with a crowbar and nail puller to ensure a completely flat surface.

Fit the shower pan onto the floor in the shower alcove area. Place shims in any gaps between the shower pan sides and the wall frames. Screw the shims to the wall with screws and a screwdriver.

Trace around the pan's drain opening with a pencil to make a clear mark of where the drain will be on the floor. Remove the pan and cut along this traced mark with a jigsaw to create a drain hole in the flooring. Attach the drain to the shower pan by placing the top half into the shower pan's drain hole and screwing the bottom lock nut over the threaded portion on the bottom of the drain with a wrench. Replace the shower pan and fit the threaded pipe into the drain hole. Mount the shower pan to the wall framing with screws and the screwdriver.

Insert the shower pan drainpipe into the shower pan drain and push the pipe up through the drain until at least 6 inches of the pipe is visible above the shower pan. Slide a compression washer over the pipe. Hammer the pipe and compression washer into the shower pan drain with a mallet to create a seal.