We provided the Owner with seven (7) possible choices to meet their criteria of a twenty (20) year roof system with proven performance, installed by seasoned applicators, while meeting stringent budget requirements. They selected the all acrylic fabric reinforced system applied over the existing single layer three ply built up cap sheet roofing. This roof has a highly reflective white surface which reduces surface and interior building temperatures to save energy and extend weathering life.
The other systems that were considered but not chosen, in part due to higher installation cost were: single ply PVC-KEE mechanically fastened with an alternate for fully adhered, a competitive acrylic fluid applied product, four ply asphalt built up roof, and APP polymer modified roof retrofit or with removal of the old roof.
Once the selection was made we prepared written Specifications for the installation, screened contractor references, conducted the on site pre-bid job walk and obtained three competitive bids.
Following a pre-construction meeting to review the Specifications with the project superintendent, work began and we performed quality control inspections at regular intervals.
The system was applied in four (4) stages. After cleaning and preparation, polyester reinforcement fabric was embedded in four gallons per hundred square feet (aka roofing “square”), followed by three additional applications of finish surfacing.
The foundation coat differs from the finish coat is several aspects. Apart from lack of UV (ultraviolet) and dirt release compounds, the foundation coat includes a surface which retains its adhesive tack even when dry to resist ponded water and improve adhesion of the finish layers.
When Santa Ana winds deposited a layer of dirt over this surface, it was cleaned with water and a stiff bristle broom then a new layer of foundation coat applied to re establish the adhesive surface.
Here are some photographs which illustrate the progress of the project.
Local ordinances permitted this type of “grey water” discharge though some municipalities differ.
Because all rain water striking the roof surface is directed to drains, the old roofing at the drains was removed, a mechanically fastened base sheet installed, followed by a smooth mid ply APP polyester reinforced modified membrane, and a granular surfaced finish membrane. Look closely and you can see the line where the old roof was removed, as well as the drain pipes from the upper level that empty into these drains.
Here one of the workers is “brooming in” the polyester fabric to insure full adhesion with no wrinkles in the foundation coat. The base coating is applied at four gallons per square with the fabric absorbing three gallons.
Note the tan color to differentiate from the finish white surface applied later, to help visually confirm full coverage.
With this system, polyester fabric was installed over all wall surfaces as well as in the main “field” area of the roof.
When this dries, the roof is waterproof. The next three (3) layers protect this foundation layer from the elements over time.
A second layer of polyester reinforcement was applied in all waterways at the base of the walls, around drains and extending out to areas that may hold water temporarily in heavy rains, and also an additional layer in front of equipment where service personnel will create foot traffic during maintenance and filter changes.
There are two adjacent spaces separated by the parapet wall in the center as well as one of the upper level roofs.