Cellular Lightweight Concrete is made of almost 100% Portland Cement. The result is that it contains very high quantities of lime (calcium hydroxide), which is a very strong alkali. For this reason, acrylic waterproofing systems may not be used. The rubber based Sealoflex® CT System is, however, ideal for waterproofing this type of substrate.
It is highly recommended that as soon as the Cellular Lightweight Concrete has cured enough to be walkable, is should immediately be primed with Sealoment Plus™ which will prevent water from precipitation from entering the substrate.