How to Add Roof Ventilation to a Flat Roof With No Soffit

Installing the Drip Edge Vent

• 1

  Pry the first three rows of shingles off the edge of the roof.

• 2

  Cut off the front edge of the roof sheathing and the top of the fascia board. The fascia is the flat board that runs along the end of the roof rafters.

• 3

  Place the drip edge vent over the edge of the roof. Nail the flashing on the top to the roof sheathing with galvanized nails. Press the flashing underneath the vent against the fascia board, and nail it to the fascia with galvanized nails.

• 4

  Nail roof shingles over the flashing at the edge of the roof.

Installing the Vent Fan

• 5

  Draw a circle on the roof that matches the diameter of the inside of the vent fan. Place it between two ceiling joists in the center of the roof.

• 6

  Remove the asphalt shingles inside the circle from the roof by cutting the shingles with a utility knife and prying them off with a pry bar.

• 7

  Cut a hole in the roof where you removed the shingles with a reciprocating saw.

• 8

  Place the fan into position over the hole, and trace the top half of the flashing onto the shingles, then remove the fan. The flashing is the flat metal part around the base of the fan. Remove the nails inside this area by prying them up with a pry bar. When installing the fan, you'll slide the top half of the flashing underneath the shingles.

• 9

  Apply roofing cement to the bottom edge of the fan around the hole.

• 10

  Slide part of the flashing underneath the shingles you removed the nails from and press the other part down against the roof.

• 11

  Nail the flashing of the vent fan to the roof with galvanized nails.

• 12

  Nail down the shingles you removed the nails from to install the fan with roofing nails.

• 13

  Seal the fan by placing silicone adhesive on top of the galvanized nails and around the edge of the flashing.