Designing Kitchens and Bathrooms - Installing cooktop hood - vent outside

Hello,

I am going to be installing a vent for my cooktop. There is a roof above the kitchen and not another floor of space so I want to utilize this and install the vent so that the air is pushed out of the house.

The problem is in cutting into (or out?) of the roof. How do I install a vent and prevent leaks when it rains? Ive never cut into a roof before so the idea is a bit intimidating at the moment.

As a side topic, I have noticed when taking down my ceiling in the kitchen that there is some wet areas in the 'attic' area. I noticed this when it rained as the wood looked wet - how do I find theses leaks?

Most fan vents include an attached flashing piece. The upper part goes under the shingles, the lower over the the shingles. Caulk with roof cement, the part under the shingles.

If the shingles appear to be in good condition, no tabs missing, granules tight, the most obvious places for leaks are where things go thru the roof. Chimneys, sewer pipes, etc. Improper or rotted flashing is usually the culprit.

Sometimes it is possible to locate leaks during a rain. The water may not be coming in where you think. It sometimes runs along the bottom of a rafter some distance before it drops off to the ceiling below.

To install the vent through the roof, do as Bill said. You will need to cut a hole the size of the pipe. Mark the center of the hole in the attic on the underside of the roof. Drill a small hole or drive a nail to mark the center of the hole. Go up on the roof and cut the hole with a jig saw or hole saw. After you install the pipe, follow Bill's instructions on installing the boot around the pipe to prevent leaks. Good luck with your project.

You could also consider venting out of a side wall in the attic, or venting out of the soffit under the eaves. Both work and there are vents available for either application.