Certain shower stalls and inserts contain trays that prevent water from leaking onto the bathroom floor. They are most commonly constructed of fibreglass and serve as a slightly concave foundation for the shower unit. Sealing a shower tray is essential for filling exposed seams and gaps where water can escape. Silicone caulk is the most effective airtight and water-resistant sealant for bathroom fixtures such as a shower tray.
Open the doors and windows nearby to ventilate the bathroom, then put on a pair of latex gloves. Limited workspace calls for optimal circulation when using chemicals.
Clean the exposed gaps in the shower tray, using a household bathroom cleaner that does not contain ammonia. Spray or pour the solution onto these areas to remove any visible build-up, then wipe it clean with a dry rag.
Cut off the tip on a cartridge of silicone caulk, using scissors. Create an opening that will dispense a bead of caulk 1/4 inch wide or less, then puncture the foil seal within the tip with a stiff wire.
Load the tube into a caulking gun. Align the tip with a joint between the shower tray and the shower wall. Squeeze the trigger and apply a bead of silicone caulk, drawing the tip of the gun along the seam.
Moisten your index finger with a damp cloth and glide it across the seal to smooth it evenly. You can also use a craft stick or the back of a plastic spoon. Allow the caulk to cure 24 hours before running the bath water.