Step 4 · Install Board and Apply Sealant

This is the step most people slow down on. Take it one move at a time — there’s no rush, and you can rewind the clip as many times as you need.

Install the panel of waterproof backer board (with the hole already cut) onto the studs and blocking. Use the manufacturer-approved screws and washers, ensuring you follow their specified spacing pattern for a secure installation. Once the board is up, take your caulking gun and apply a continuous, unbroken bead of waterproof sealant (such as Schluter KERDI-FIX) to the exposed front edges of the horizontal blocking inside the opening. Immediately after, apply another continuous bead of the same sealant to the entire back perimeter of the niche's mounting flange.