Why Do Vinyl Pools Have Foam Behind the Liner?

Wall Foam

• The foam used behind vinyl swimming pool liners is composed of 1/8-inch closed cell polyethylene foam. The foam is designed to protect the lining from damage and exposure to the steel pool wall or frame.

Smooth Surface

• A primary reason why pool installers add the single layer of protective foam behind the liner is to provide a smooth surface for the sides of the pool. Above-ground pool walls are typically constructed of steel or aluminum, which are very hard to the touch. The foam layer provides for a cushioned and smooth pool wall surface and protects the liner from any seams in the pool wall where nuts or bolts may protrude. The foam also keeps the vinyl liner stretched at all times, preventing divots from forming. Inside these divots is where algae can grow.

Insulation

• Many pool owners may opt to use electrical or solar powered heating systems for their pool. Without the protective foam, the pool would lose a lot of the heat created by those systems. Although the foam is not designed to insulate the pool, it is effective in reducing heat conduction, which can lower the temperature of the water. It acts as an insulator to the pool because during nighttime hours the steel can get cold to the touch and affect the pool water temperature. The foam blocks the cold steel from lowering the water temperature.

Installation

• The foam is almost a routine part of pool installation because of its proven degree of practicality. The foam is applied directly to the pool wall prior to installing the liner. The foam is sometimes self-sticking, but other types need to be adhered using a special adhesive spray.