Sooo sorry for delayed response. We are not as active on this site as others. I decided to answer late so that future customers may be able to benefit from your question as your project has probably come and gone. These pebbles are bonded to a mesh that is installed on a wall or floor like a typical piece of ceramic tile. It looks great and is not prone to water penetration as long as installed properly. We installed over a hardi backer and we applied a substrate called red guard that prevents water from penetrating through to the walls. The part you have to be careful with is the faucet handle. Ideally this would be installed on a flat surface so that it can be caulked and sealed all around preventing water from seeping through over time. This is difficult to do when the handle is on top of a rocky, uneven surface. Other than that, this is a excellent product to use in the shower. Hope that helps!