Building Management needed a cost effective cure for the old aggregate (slag) surfaced coal tar pitch roof on this building.
Roof removal always adds cost – with a high rise, bagging the rock, old roofing material and insulation for removal through freight elevators is even more labor intensive.
We’ve done this before, and with proper equipment it is just a matter of paying for the extra time, yet if this step can be avoided the cost savings are significant.
Here we were able to specify and provide quality control for the installation of a multi layer cold process asphalt system reinforced with both chopped fiberglass and polyester mesh fabric.
The preparation involved removing all the loose aggregate, thoroughly power washing the roof surface, and cutting out and replacing small areas of damaged insulation.
Preparation took longer than anticipated cleaning decades of airborne contaminants embedded in the irregular surface, but this step is essential and must be done correctly to ensure correct adhesion of the fully adhered new roofing materials.
A leveling base ply of chopped fiberglass and asphalt emulsion was followed by two layers of polyester fabric embedded in additional cold process asphalt.
The benefits of bentonite clay stabilized cold process asphalt emulsions are three fold: 1) It is resistant to ponding water in areas of less than ideal drainage, 2) moisture vapor permeability eliminates blistering in the finished system, and 3) because the asphalt is never heated or oxidized, the weathering life is enhanced.
This system was finished with reflective surfacing.
Ten years later, with maintenance servicing on the coating, the system continues to perform well.