A four-inch minimum plumbing vent stack penetrates an exterior roof deck assembly consisting of thermal insulation and a coverboard beneath a multiple-ply modified bitumen roof membrane. A two-piece soft metal pipe flashing has its flange set in compatible roof cement and is primed before receiving a modified bitumen membrane stripping ply. Compatible roof cement or sealant is applied at the penetration-to-membrane juncture. The top of the flashing is rolled into the pipe approximately one inch without fastening to the cap to allow for building movement.
EXTERIOR ROOF DECK THERMAL INSULATION COVERBOARD SET FLANGE IN COMPATIBLE ROOF CEMENT (FOR ROOF SYSTEMS WITH FACTORY-APPLIED GRANULE SURFACING, THE PIPE FLASHING FLANGE AND MULTI-PLY MEMBRANE STRIPPING CAN BE INSTALLED BETWEEN THE BASE PLY AND GRANULE-SURFACED SHEET) MULTIPLE-PLY MODIFIED BITUMEN ROOF MEMBRANE PLUMBING VENT STACK 4" MIN FLANGE MIN 4" COMPATIBLE ROOF CEMENT OR COMPATIBLE SEALANT AT PENETRATION TO MEMBRANE JUNCTURE MODIFIED BITUMEN MEMBRANE STRIPPING PLY - PRIME FLANGE BEFORE STRIPPING 2-PIECE SOFT METAL PIPE FLASHING TOP OF FLASHING ROLLED INTO PIPE APPROX. 1" DO NOT FASTEN TO CAP TO ALLOW FOR BUILDING MOVEMENT
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