Surface Preparation
All surfaces must be clean and dry, and free of any dirt, dust, oil, surface chemicals or other contaminants that may interfere with optimum adhesion. All loose gravel, if present, shall be removed by power sweeping and/or vacuuming.  Remaining gravel shall be power spud to achieve  the smoothest surface possible. Any unsound areas in the roof, i.e. blisters, delamination, deterioration, moisture saturation, severe corrosion, sharp projections, ridges, etc. shall be repaired or replaced. 

New asphalt shall be exposed to ambient conditions for 45 to 60 days before coating.  Deteriorated or badly corroded metal shall be replaced.  Rusted areas shall be mechanically abraded to remove all loose rust and then primed with UNITED’S Acrylex 300.  New metal roofs exhibiting any type of surface film shall be washed with a vinegar or muriatic acid solution or equivalent to totally remove this film.  Low areas that hold excessive ponding water must be brought into conformance by installing additional drains or adding additional slope to existing drains. 

Surfaces that are contaminated with oil, grease, embedded dirt, loose paint or coating, etc. shall be cleaned using United Cleaning Concentrate (UCC).  High-pressure power washing may be necessary to remove tightly adhering contaminants. Rinse thoroughly with clean water to remove all traces of the UCC cleaner. If roof does not require chemical cleaning, thoroughly sweep, vacuum, or blow down roof to remove any dirt, dust or other loose contaminants. Contact UNITED’S Technical Service Department for additional surface preparation procedures on the specific substrate being coated.