Bituthene Curb Seal is used to wrap around the 3 stacked 2" x 4" wood pieces and inside of OneLiner shower pans to waterproof the curb.
The bituthene shower pan curb waterproofing is sold in 9" wide x 42" long pieces. This size is enough for 1 - 30" Kirb Perfect and then 6" for either end of the curb where your curb framing meets your wall framing. If your curb is more than 30", additional bituthene curb seal is recommended.
For Product Installation, see "Step 4 Cutting and Waterproofing" of our OneLiner Installation videos.