Install Bath Fan Vent On Metal Roof

Use rigid metal ducting aluminum or galvanized steel with lengthwise seams facing up and joints sealed with foil tape or duct mastic or rigid plastic pipe.

Install bath fan vent on metal roof.

In this video this old house general contractor tom silva shows how to properly install a roof mounted bath fan vent. From the roof find the nail and use the utility knife to cut roof shingles from around the nail. Fwiw here is a url to the photo of the roof. Try to keep it close to the fan location.

Start in the attic and drill a hole through the roof in the desired vent location. Climb into the attic and clear away any insulation from around the hole. From up on the roof use a jigsaw or reciprocating saw to cut a 4 in. Install the roof vent install the roof vent by sliding the top flange under the shingles above it and resting the bottom flange on the shingles below.

For optimum performance locate it between the shower and the toilet. The internal construction of the house does not permit me to vent the bathroom fan elsewhere. If you vent through a soffit where attic vents are often located the moisture will get sucked back up into the attic or roof venting. Secure the vent flanges with roofing nails before installing the shingles.

Draw a mark on the bathroom ceiling where you d like to install the vent fan. Leave the drill bit sticking through the roof so you can find the hole. Also this is the section of roof that gets hit directly with heavy winter winds. Use an extra long 3 8 inch diameter spade bit to bore a reference hole through the ceiling and into the attic.

Prepare the roof area. From inside the attic drive a nail through the roof directly above the bathroom vent fan. This will involve determining the placement of the vents. I intend to install the roof vent cap in the section to the right of the section where the plumbing vent is shown.

Apply roofing adhesive on the underside of the flanges to seal. Center the nail between two rafters.