Ventilate Your Foam Roof Insulation in 4 Easy Steps


If you want to insulate your roof with foam, it is important that air is able to freely flow around your foam insulation in order to prevent moisture from gathering. Ventilation is just as important as insulation when it comes to how you structure your roof. Here are the four steps you'll need to follow to ensure that your foam insulation has the right amount of installation as well as ventilation.

#1 Put the Sheathing in Place

In addition to insulation, you are going to need to put sheathing on your roof. Sheathing is a thin material that goes on top of your rafters and creates a barrier between your rafters and your insulation. You should use sheathing that is at least one-inch thick, although you can use sheathing that is a little thicker if you want to increase the insulation properties of your home.

As you use a nail gun to secure the sheathing to your rafters, make sure to leave a one-inch along the ridge of your roof. The ridge of your roof is the line that goes through the middle of your roof. By leaving a gap along the ridge of your roof, you will provide an area for air to flow.

#2 Install Plastic Long Forms to Maintain the Gap

To preserve the gap that you created when you attached the sheathing to your rafters when you apply the foam installation, you are going to need to protect that gap. You can protect that gap by putting a long plastic form right next to each rafter on your roof. The long plastic form should be installed along the entire length of your rafters. You don't want to nail or glue these in place; they are just a placeholder. Generally, you can just wedge them in place next to the sheathing along your rafters to ensure that there is an air gap in your roofing insulation once the spray foam is applied.

#3 Apply Spray Foam to Your Roof

Third, you are now ready to apply the spray insulation foam to your roof. Before you apply the spray foam, make sure that you are all covered up, including a breathing mask, goggles and gloves. You don't want to get the foam on yourself or breath it in.

Once you are covered up, you are going to want to work one area at a time. Pick one area or length of rafter that you want to work on, turn on the spray foam machine, and move the wand left to right, working from the center of your roof down to the outer edge. Working one section at a time will allow you to check your work and ensure that the foam is applied on thick enough.

#4 Sculpt the Foam Insulation

Fourth, when the foam is in place, you are going to want to go back and sculpt the foam. Sculpting the foam is easy; just use a razor blade to cut away any excess foam that got into areas where you didn't want it to be.

#5 Remove the Plastic Long Forms

Finally, after the foam has had time to cure, you can remove the plastic long forms that you wedged next to the rafters in order to ensure that your roof had enough ventilation along with insulation. You may need to use a little force to pull it them out of place. You can recycle or dispose of the plastic long forms once you have removed them from your ceiling. 

To learn more about this process or get additional assistance, visit resources like


5 June 2017

metal or shingled roofing - what do you choose?

I spent weeks researching metal and shingle roofing to try to figure out what would be the best material to use on my home. I weighed the costs, the length of life, the amount of maintenance required and how well each type would hold up to high winds and strong storms. After compiling all of the information that I needed to make an educated decision about the roofing for my home, I created a blog. This blog is meant to help other homeowners decide which roofing material would be best for their homes now and many years into the future.