How to Cut a Vent Hole in a Shingled Roof

What You'll Need
Ladder/ Scaffolding
Plumb bob
Circular saw

A shingled roof is a roof of separate elements overlapping each other. These types of rooftops are usually constructed in European and Scandinavian countries. Cutting a vent hole in a shingled roof is a complicated task and you need to be extremely alert whilst doing it. Below are some guidelines that will help you in cutting a vent hole in your shingled roof.

Step 1 - Take Necessary Precautions

The roof is a very dangerous place to work. It's easy to lose your footing and fall over the edge. Do not lean on or over edges of the roof. Instead use a ladder or scaffolding while working on the edge. It is advisable to have someone stand near you while working, so that if any unforeseen incident happens, it can be taken care of immediately. You must avoid working with shingles in cold weather or on rainy day as shingled roofs can be slippery and dangerous.

Step 2 - Mark the Area

After taking adequate precautions, advance to the next step. Decide what kind of vent you want to use. Then use a plumb bob to mark the hole where you want to make a cut to get the vent through. From inside hold the plumb bob against the roof and then place the pipe in the center. A heavy nut or washer attached to a string is an alternative that you can use if you can’t find a plumb bob.  

Step 3 - Remove the Shingles

Next you need to remove the shingles that would act as a blockade while you are cutting the vent hole. Very carefully, dismantle each shingle seal down strip. After you have dismantled the shingle seal down strips, using a screwdriver you need to take out the nails that hold the shingles from in between. Some of the shingles might easily slide off without having to pull them.

Step 4 - Cut the Vent Hole

After you have removed the shingles, you now need to cut out a piece of the asphalt felt underlay using a circular saw. The hole that you cut should be near the edges because it is easier to remove the shingles at the edge than the middle. The hole you cut needs to be at least 2 inches larger than the hole you will cut in the plywood. You don’t have to be very precise while cutting the hole; the hole can be cut roughly and should preferably be either oval or square in shape. Again no accuracy is needed; just a rough big hole will fulfill the purpose.

Step 5 - Pass the Vent Tubing

Then pass the vent tubing through the plywood and check if the edge on the bottom of the vent flashing is going towards the direction where the cut is made in the roof. Once it is in place, cover the roof properly with the shingles, leaving no bare area. You're now done with your project.