CTLGroup conducted an evaluation of the existing ballasted coal tar pitch roof membrane at the Evanston North Branch Library. The assessment showed little to no slope to drain water off the roof and little roof insulation in place, as well as deteriorated sealant joints at the brick masonry and joints in the copingstones of the parapet wall.
Our team determined that, due to prolonged, extended water infiltration of the parapet wall, the existing wood rafter was significantly deteriorated and no longer capable of supporting the anticipated snow loading. CTLGroup prepared repair designs, construction documents, and specifications for the replacement of the roof, repair of the masonry, and emergency repair and replacement of wood rafters.
Work included replacement of the existing roof with an EPDM roof membrane to accommodate the low slope to drain and protect from future water infiltration, new gutters for optimized water sheading, and new insulation. A traffic coating membrane was applied to the parapet wall which functions as a waterproofing membrane for the coping stones. Additional work included rebuilding 75% of the parapet walls, cleaning and removal of efflorescence of the brick masonry, removal and replacement of deteriorated mortar & sealant joints, removal & replacement of deteriorated coping stones.