Cold-applied polyurea-based membranes are used in either a spray-on or a roll-on application, depending on area size and accessibility. In case of a concrete flat roof, crack repair and patching are done, as needed, ahead of the waterproofing membrane installation.
The roof surface must be prepared ahead of a polyurea-based waterproofing membrane installation. This usually involves the removal of gravel, rigid insulation and fleece, and the cleaning of the concrete surface. Crack repair and patching are done next, as required. The membrane is then either sprayed on or rolled on, depending on project requirements. If gravel is not used for UV protection, an aliphatic (UV-protection) topcoat is applied; otherwise, a less expensive aromatic (non-UV) topcoat is used.
If a metal roof requires a waterproofing membrane, its surface must also be prepared as it cannot be rusty, oily or have debris, for proper adhesion. A sand blaster or grinder can be used to clean the metal surface to ensure it is rust-free. Oil is removed with a solvent, as needed. The surface is then coated with a primer, followed by a polyurea membrane.