How to Flash a Gravel Roof Jack

Clear the roof substrate around the vent pipe of loose dirt, debris and gravel. Spread plastic roof cement thickly for 6 inches around the protruding vent pipe. Lay down the base ply of roofing felt, cutting it close to fit around the pipe. Press the roofing felt down onto the roof cement. Spread another layer of plastic roof cement on top of the base ply.

Select a roof jack that fits the diameter of the vent pipe. Slide the roof jack down over the pipe and press the bottom flange down onto the roof cement. Nail the flange down with roofing nails spaced about 2 inches apart around the circumference of the roof jack’s flange. Paint the flange of the roof jack with asphalt primer. Cover the joint where the roof jack joins the pipe with flashing tape and plastic roof cement.

Coat the bottom flange and lower quarter of the roof jack with hot asphalt roofing and lay the next ply of roofing felt down around the roof jack, cutting the felt to fit closely around the jack. Lay down more hot asphalt and roofing felt around the roof jack and the rest of the roof until the roof is sufficiently built up. Cover the roof with roofing gravel, including the area around the roof jack.. Paint the roof jack if desired.