Installing a roof vent and vent cap: A Step by Step How to Guide

There are multiple reasons to install a vent on your roof. From venting your main drain, a bathroom fan, a water heater, a fireplace to a kitchen hood. All of these require a roof vent. The hood that you use might differ for each of these but the installation is generally the same. Let’s take a look at how this can be done. 


Preparation is everything

When you go on the roof, it is essential that you wear protection. You can attach your ladder to the house with a strong cord. Wind can easily take a ladder down so make sure that it is standing sturdy. You might want to wear fall protection as well. This is not perfect as someone will need to help you when you fall down. If you have to wait too long, the effects could be deadly as the harness restrains your body.

It is still better than nothing and a harness and cord can help you a lot if you trip and fall. For this reason, you might want to take a look at them. There are harnesses that connect on your front and others connect at your back. If you have to perform tasks, it is easier that the rope connects to your back so that the cord doesn’t get in your way. It can take some time to get used to working with a harness but can be well worth it. A lot of accidents happen when people trip and fall. For this reason, more attention is being paid to wearing appropriate protection when you work on the roof. 

Get the right materials

Wear sturdy boots as roofs can be slippery. Don’t work on them when they are wet or when there is a lot of wind.

Find the right vent hood for your application. Some vents have a backflow protector. This makes sure that dirty air doesn’t go back inside. You can also get vents with screens that keep dirt and insects out. You will need a hammer, nails and a drill.

Locate where to install the hood

The first step is to remove insulation if you have any from the area that you want to install a vent in. You can add a nail in the middle of the raft. The goal is to drive it right through the sheeting. This will allow us to see where on the roof the vent will be located. This is easy for when we go on it. Make sure that no electrical lines or plumbing pipes run nearby. It is best to install the hood in the middle of the raft. Don’t install it too close to the top or bottom as this can lead to cracks and leaks.

Measure the hood of the vent. The nail that we have installed before can be used as a reference when we draw the hole that is needed. You can use a utility knife to cut the shingles. If they are made out of clay or concrete, you might have to remove them and cut the sheet behind them. You can slide the hood under the shingles to see if your hole is big enough.

In the next step, we are going to drill a hole in the roof with a hole saw drill bit. The nail can be once again used as a reference. 

Installing the duct

Now we go back to the attic and install the duct. 

In some instances, you will want to add an insulated duct. This is often a flexible pipe. For water heaters metal drains are often used for this as these last longer. Check your local code as they might specify what drain is needed. You can add a piece of metal that you connect with tape and tighteners to this at the end to make the connection. 

Nail the metal piece down

You place the metal part through the roof. It is possible to cut flaps into this metal piece, fold these and nail it down. This secures this part to the roof and makes sure that it doesn’t fall back in the attic. 

Add caulk under the hood before you slide it under the shingles. Don’t add caulk all around it as moist air has to be able to escape. Then you push the hood down and make sure that it has a tight seal. 

Secure the hood or cap to the roof.

Add nails to secure the hood. You can add sealant to the singles to get it secured even more. If you have a roof that is made out of harder singles, you can add them again. Make sure that everything is properly sealed. 

Check the installation

Check if no air or heat is escaping after the installation. You can use a heat camera to do this or use a visual inspection. You might want to inspect your hood and the installation every 6 months to make sure that nothing is going wrong. It is possible that birds are building nests nearby or that insects get stuck in the hood. Make sure that it is clean so that the hood can vent the dirty air. This can have a big impact on the efficiency of your devices so it is important to keep an eye on it.

To conclude, it is possible to install a roof vent yourself if you have the right equipment. It can be quite dangerous to do this without a harness and safety equipment.

 A vent can often last a long time so it is a great idea to pick one that is made out of strong materials. It is also important that you get the right vent for your applications. A lot of people pick the wrong one and get dirt or debris in their drains. This can make a water heater or fan break.