KBRS Waterproofing Pack #1 Shower Installation Kit Includes: Liquid Waterproofing Membrane, Seam Fabric, and Marine Grade Polyurethane Sealant (2 Tubes)

I think this stuff will waterproof very well as a 2nd layer over the tubes of sealant, however you need to be careful and you need to go slow. Also, don't use costly painting tools. You aren't going to be able to clean this stuff off your brushes and rollers and it makes a mess of your hands. I used gloves and I thank God that I did because they were covered with the paint as were the brush handles. Lastly, don't try to cut the gauging fabric with cheap scissors. You need fabric shears to cut the fabric. Cheap scissors will just wedge the fabric in between the blades without cutting it. I used Fiskars fabric scissors that cost about $15. Those worked great.The problem with the fabric is that it's not easy to get it tight around outside corners and tight into inside corners. Also, the paint doesn't always stick to the sealant. That combination of issues created voids up to 1/2 inch wide underneath the fabric all along the outside top corner of my shower bench after the water proofing paint dried. I could press on those voids with my finger and they would move in and out. You can't apply thinset to that and expect it to work. It will crumble. I couldn't leave the voids, so I cut them out and repaired them with more of the waterproofing paint. After that repair paint dried, I added more fabric to the areas that I had to cut out.On the inside corners, no matter how tightly I thought I got the fabric into the corner, there were spots where the paint didn't stick to the sealant and the corners were very rounded after the paint dried. When I pressed into the corner with my finger, I could feel the void underneath. I used a razor blade to cut into those corners and press them back. I then applied more paint, let it dry, and then re-applied more fabric in those repaired spots.Don't be in a rush to work with this stuff. You need to take your time, let it dry for a full day, and then carefully inspect every bit of what you did for voids and spots that didn't get full coverage. Then you need to repair the voids and cover the thin spots. Also, don't expect to get away with 1 coat. You will need at least 2 coats. It's best to just paint any thin spots during the careful inspection, and complete all repairs. Don't apply the second coat until all repairs have been completed and fully dried.I would definitely use this stuff again. Thankfully, I was able to take my time. You might as well figure that this stuff will take a few days to get totally right. You aren't likely to go from sealing to tiling in a day. I'd plan on the sealing taking at least 3 days.