Using Spray on Insulation for Ductwork

  • 4-8 hours
  • Beginner
  • 75-250
What You'll Need
Spray Foam Insulation Kit
Wooden Doweling
Plastic Sheeting
Foam Spraying Machine
Utility Knife
Protective Clothing

Spray on insulation is making insulating duct work very simple. Insulation is very important because it will help to reduce energy waste and heating costs. With heating costs rising every year ,spray on insulation is starting to appeal to more and more people. Once you install the insulation, you can save yourself a considerable amount of money every year on your heating bills. Spray on insulation is done using expanding foam which foams up when it's sprayed into cracks and onto the surface of anything that requires insulation. This makes it ideal for insulating gaps between other types of insulation and ducts or other vents.

Step 1 - Preparation

Spray on foam insulation is a liquid which is very sticky, it's important to wear protective clothes which you don't mind getting dirty. Once the foam is dry, chances are you will not get it off your clothes. You must also wear a mask because the fumes from the spray on insulation can be bad for your health. A few people will have their own foam spraying machine, however, they can be rented from most tool shops or home improvement stores.

Step 2 - Loading the Machine

Read the instructions carefully for the proper installation of the form. Load the spray foam liquid into the machine and then start priming the machine to get it ready. Switch the machine on and then you should be ready to go.

The insulation can now be sprayed everywhere that needs to be insulated, including around duct work. The best thing about expanding foam is that it's very easy to squirt it in between even the tiniest of gaps, the foam will then expand and fill the void completely without you needing to do anything. The foam will expand between 4 and 100 times its original volume. A piece of wooden doweling can be used to push the insulation into all of the cracks if needed.

If you're not sure how to use the machine, be sure to read the manual for more information. The manual should show you where the controls are, which will make it possible to control the flow of foam.

Step 3 - Allowing to Dry

You will need to allow the spray on foam plenty of time to cure and dry before doing anything else to it. Read the manufacturers directions to find out the length of time required for your specific foam. The drying time can vary from a couple of hours to 24 hours, depending on the brand and the type of application.

If you are applying the insulation to areas which will be visible, then you can trim the insulation back by using a sharp knife. The foam cuts easily and with a bit of patience you should be able to ensure that it's level with the duct work and the wall. Then you can paint and finish the wall to match the rest of the room.