How to Repair a Leaking Flexible Duct

What You'll Need
Duct tape
Paint brush
Sealant - can use Mastic
Caulk mastic
Caulking gun
Foil tape
Panduit strips
Putty knife

Fixing a leaking flexible duct is important because you don't want to waste money and you certainly don't want your home to get to an extreme temperature. Repairing a leaking flexible duct is actually a pretty simple task if you know what to do. Here are a few tools that you will need, along with some quick steps to help get you through the process.

Step 1 - Find the Leaks

The first thing that you need to do is find the actual leaks in the duct work. You can typically do this pretty easily as long as you have access. You need to turn the temperature on and then check for air coming out or even holes or problems in the duct that you can see or feel. Also, check to make sure that there isn't any duct work that has come off completely. Many times you will find an entire section gone that needs to be replaced.

Step 2 - Repair Ducts

There are a few different ways that you can repair the flexible duct, depending on what went wrong in the first place. First, if there is just a loose connection, a panduit strip can do the trick. You can peal back the outer layer and then use pliers to attach the new panduit strip. You will want to pull back the outer layer and attach the strip to that. You may want help from someone to keep it steady. Then, you can use sealant and a paintbrush to make sure that it is secure.

Another way to fix it is by using mastic tape. If you find that there was just a small rip, you can use duct tape to hold the rip together as you work on it. Then, use a paintbrush to coat on a little bit of mastic sealant and press the sides together. Once everything has dried, use some mastic tape in the mean time to keep it all secured.

Finally, if you find that there is a hole that can not be mended together on each side, you can use a caulking gun and mastic caulk to fill it in. Put the mastic into the gun and then slowly fill it in. You will want to make sure that you let it dry for about 24 to 48 hours before you are actually using the duct work again so that it doesn't come undone or get dust and debris in it.

Step 3 - Check

Now that you have finished repairing, you will want to check to make sure everything is working properly. Give the duct time to set for a day or so and then test it out. Turn the temperature up or down again so that air should be running through and obvious to you. Then, make sure there are no leaks to be found.