Vent pipes are usually flashed with either a lead collar or boot and a lead flange. The top of the boot is then placed over the vent pipe. The lead sleeves could be cut flush with the top pipe. Counter flashing would then be installed with the lead 2 inches below the pipe’s inside and 4 inches below the pipe’s outside. Roofers usually just wrap the sleeves inside the pipe.
Rubber Flange Roof Vent Flashing
A rubber flange is another popular way to flash vent pipes. This type of flashing is most commonly used for metal roofs. Vent pipes typically measure 1 1/2 to 3 in.
Installing shingles in areas where there is a vent pipe will require you to install the shingles right up to the edge of the pipe. You will need to make holes in the shingles if they run into the boot.
Install the flashing above the pipe and the underlying roofing shingles. Install the bottom half of the lead flashing on top of any shingle below the pipe. The top half of the flange should be placed directly on the underlayment. The shingles above will cover the top part of the flange. Install your shingles by embedding the flange into roof cement. ALWAYS INSTALL A FULL-WIDTH SHINGLE OVER THE PIPE. To rearrange the shingles, place a single tab on the course of the shingles.
Continue to shingle above and around the pipe, trimming the shingles as necessary to fit around it. To ensure that no nails get through the flashing, nail the shingles to the vent pipe. When trimming the shingles, leave about a half-inch between the shingle & the sleeves. This is so debris doesn’t get between the shingle & the vent pipe. The shingles don’t have to be covered at the bottom of the flange. Many roofers recommend that you leave the bottom third of your flange uncovered. Although it is less likely for debris to accumulate, it does not look as neat.
You can also embed roofing cement in roofing cement beneath low-sloped roofs to provide additional protection.
Installing larger vents, such as heater vents and off-ridge vents, you will need to nail the vent’s lower edge. Apply roofing cement to the flange. Apply shingle to the vent, trimming as necessary. NAIL NOT INTO THE VENT FLANGE.
This post was written by Ted Williams! Ted is the owner of A Old Time Roofing which is the premier roofing contractor in Clearwater FL! Ted is a Master Elite Weather Stopper GAF Roofing Contractor, a double award winner of Best Steep-Slope Contractor from GAF and achiever of Master Elite Consumer Protection Excellence from GAF. He has been serving the Pinellas County area since 1978. Old Time Roofing has a tradition of quality workmanship, servicing residential and commercial properties.