I had to tear down the wall around the shower. When I replaced the plastic laminate I trimmed it a bit leaving a gap. I used regular chemical sealant that comes in a tube but after a few years it turned black and moldy. When I ripped it apart I found that water had seeped under the laminate. I let it dry for a few days and used this product to fill gaps after resealing with chemical sealant to fill the gap and support the sealant bead. Voila! Perfect clean permanent renovation. I should have used that in the first place!