OATEY 11919 1.5 in. – 3 in. Thermoplastic All-Flash® No-Calk 11.25 in. x 15 in. Base Roof Flashing

The Oatey 11919 All-Flash No-Calk flashing covers vent pipes from 1.5 inch up to 3 inch. The patented All-Flash collar design is what lets one part cover that range, so a crew can stock a single flashing instead of a separate one for each vent size on a re-roof.

The plastic base works on pitches from 0 to 45 degrees, so it covers everything from a dead-flat deck up through a 12/12 roof. Past 45 degrees it is out of range.

No. The 11919 is specifically not for hot-mopped or built-up roofs. You also should not put petroleum based products or paint on the collar or the thermoplastic base, since those attack the plastic. For a BUR or mod-bit assembly, use a metal-base flashing instead.

Yes. The 11919 is approved for Type B installations and carries a 180 degree F continuous heat rating, which is what lets it go over a B-vent rather than only a plumbing DWV stack.

No caulking at the pipe. The self-sealing collar slides down over the vent pipe and seals against it on its own. The base still gets shingled in and fastened per normal roofing practice, but the pipe-to-collar joint is designed to be caulk-free.

The base measures 11.25 in. x 15 in., which gives you room to lap the upper edge under the next shingle course and run the lower edge over the course below. The piece weighs about 0.608 lb, light enough to carry a stack up a ladder in one trip.

The thermoplastic base on the 11919 is the low-maintenance choice on shingles: nothing to bend over the pipe, no torch, and the collar seals itself over anything from 1.5 to 3 inch. Lead still has a place where a jurisdiction or a spec calls for it, or on hot-mopped and built-up assemblies where this plastic base is explicitly not allowed. Keep paint and petroleum products off the plastic either way.