Brookhaven Station TPSS and Ancillary Building Roof Rehabilitation

Scope: Traction Power Sub Station: Tear off, remove, and discard all existing EPDM roof down to the bare concrete deck. Inspect all concrete deck thoroughly for cracks and deficiencies. Seal all nonstructural cracks with specified products. Refer to Basis-of-Design products section below. Remove all existing roof-to-wall metal flashings and one roof-to-roof expansion joint. Replace with new pre-formed expansion joint cover, attached with term-bar, and covered with stainless steel twenty-four (24)-gauge metal flashing. Clean and remove all existing caulking and sealant from the through-roof conduit banks at four locations (large pitch pans). Inspect, clean, and reseal all conduit transitions with the product recommended by the roofing manufacturer. Pressure wash all interior parapet walls where roof-to-wall terminations will be installed. Clean and prepare existing substrate decking to receive a new roof membrane. ROOF DECK LEVEL: Survey the deck elevation to determine low spots on the roof causing the ponding. ROOF OVERFLOW: Core drill a 3-inch diameter hole in 8-inch thick concrete south parapet wall for overflow and line with a stainless-steel pipe extended a minimum of 12-inches outside the face of concrete wall. Seal all transitions around overflow pipe penetration. Provide concrete spla block at the ground level. Level areas with specified self-leveling concrete to address all low spots. Verify compatibility between the concrete topping material and adhesive to be used to adhere to coverboards with the roofing manufacturer. Provide, and install a new forty (40) mil vapor barrier over the concrete decking substrate and turn up a minimum of six (6)-inches high on all perimeter walls. Provide and install a fully adhered ½-inch high-density cover board. Provide and install a new fully adhered one hundred thirty-five (135) mil PVC FleeceBack roof system per manufacturer’s instructions for the specified thirty (30) years warranty. Provide and install a new fully adhered sixty (60) mil PVC Fleece-Back wall flashing detail membrane. Provide and install a new expansion joint cover plate at the transition between the TPSS and the ANCILLARY ROOF. Water test all repaired and replaced areas per MARTA’s Roof Water Testing Procedure. Ancillary Building Roof: Inspect all roof areas and transitions thoroughly for roof membrane and coating deficiencies. Prepare all membrane transition joints by removing existing coating and re-coat with roofing manufacturer recommended coating for a long-term warranty. Seal all roof transitions where deficiencies are noticed. Install 4-inch diameter drainpipe from the damaged existing drainage system and direct the water to the existing roof drain. Support horizontal drainpipe on the roof membrane with recommended protection and with a minimum 1/4-inch per foot slope.

Division 07 -

Thermal and Moisture Protection, Dampproofing and Waterproofing, Thermal Protection.