A liquid membrane constitutes a material applied to a surface to prevent water from leaking through the surface. As the name suggests, liquid membrane comes as a liquid, usually the liquid form of a plastic or rubber polymer. Applied with a pain brush or roller, liquid membrane dries to form a waterproof bond with the material to which you apply it. In shower stalls, liquid membrane provides various uses. You can apply it to a shower pan to strengthen the material, use it in place of a shower pan, apply it to the walls of the stall to prevent leakage or use it to repair cracks in the shower pan or other parts of the shower stall.
PVC Shower Pan
Polyvinyl chloride (PVC) constitutes a type of plastic, and one of the two plastics -- CPE is the other -- commonly used for shower pans. Manufacturers use PVC for shower pans because it's leak-proof and impervious to erosion under the force of water. Two types of PVC shower pans material exist. You can purchase pre-made shower pans already cut to specific dimensions, or you can purchase a sheet of PVC shower pan material cut to the dimensions of your shower stall.
The most obvious difference between liquid membrane and PVC shower pans lies in the materials. PVC constitutes a type of plastic used as a solid layer between a shower floor and the bathroom floor. A liquid membrane creates a bonded, waterproof layer that you cannot necessarily see or easily work with once dry. Liquid membrane prevents leaks, though if the material itself weakens and leak, finding the leak can prove difficult because you cannot easily see the material. Regardless of the material you use, always pour water on your shower pan before applying the surface material to check for leaks.
You can apply PVC as a shower pan in any situation because it constitutes a solid material. As long as you adhere it properly to the structure of a shower stall, PVC shower pans sit on top of any material used in showers stall construction. Liquid membranes only adhere to certain materials, like tile and concrete. Loose materials like mortar or laminated materials like certain plastics may prevent a liquid membrane from forming a bond. Always investigate the properties of a liquid membrane before purchasing it for a specific application.