When using asphalt roll roofing, follow these tips for secure watertight roof flashing installation.
Where to Install Roof Flashing on an Asphalt Roll Roof
Install flashing at roof valleys, around dormers, vents, skylights and chimneys. Use a generous width of polymer-added bituminous asphalt sheeting for flashing under asphalt roll roofs.
Install an asphalt roll surface with polymer bituminous flashing on a low-pitched, but not flat roof. Water can accumulate in the roofing or flashing on a flat roof causing ponding, that will eventually result in rotted underlayment and a roof leak.
How to Install Polymer Bituminous Flashing
Provide 6 inches of overlap under each side of the flashing. Lay it from the bottom of the roof to the top, ensuring 4 inches of overlap at each base line. While this flashing is self-adhesive, it is best to nail down the flashing into the roof underlay at the top of each sheet. The adhesive can dry out in hot weather.
How to Create Joints in Bituminous Flashing
Fold the flashing over at corners and secure it with either hot or cold asphalt. Make the finished joints smooth so the asphalt roll roofing will lie flat over them.
Install bituminous flashing on roof eaves where ice and snow buildup occur.