Gladon's Wall Foam is a closed-cell 1/8inch protective foam barrier that is attached to the interior wood, metal, or concrete pool walls with a spray-on adhesive at the time of installation. The pool liner is then installed over the Wall Foam, creating a smooth surface that prevents algae from forming in hard-to-clean divots on the surface of the liner. This simple addition also prevents rust, corrosion and other potential pool wall decay from deteriorating your pool liner. No punctures, no leaks, no stress.A benefit of Gladon Wall Foam is that it acts as a barrier to heat loss, keeping your pool at a comfortable temperature and saving on heating costs. Use Wall Foam when constructing a new above ground pool or replacing a liner.