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Window sealing secrets from a seasoned pro!

How to seal windows with spray foam for a flexible draft-free solution

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Sealing a structure’s windows can significantly reduce its carbon footprint. We have prepared a detailed guide listing the supplies needed for the job and the steps to seal an outdoor window.

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Why do you need to seal windows?

Installing new energy-efficient windows can boost your home’s energy performance. However, many people forget to seal off the gaps and cracks along the perimeter of the window frame. The resulting air leakages erase the benefits of having energy-efficient windows.

When replacing or installing a new window, builders normally frame an opening two inches bigger than the window. This leaves room for the jamb and window frame. The wiggle room also allows for the proper positioning of the window. However, some gaps may be left once the installation job is complete.

To ensure the work is done right the first time around, Myron Ferguson uses Loctite Tite Foam Window & Door to seal these gaps. This insulating foam sealant eliminates air leakages, boosting your home’s energy efficiency and comfort.

Supplies needed to seal an outdoor window

Myron Ferguson, a seasoned drywall and building performance contractor, understands the importance of having the right tools for the job. When air sealing windows, you don’t just want to know how it’s done, you need to have detailed information about the process. Some of the important questions you must address include:

  • What type of expanding foam should you use to seal windows?
  • Do you need safety gear?
  • How do you trim away excess foam?


To answer these and other questions, here is a list of the supplies needed to seal a drafty window.


Loctite’s expanding foam is designed to create an effective seal along the perimeter of windows. The canned spray foam bonds to most building materials including stone, brick, wood, concrete, PVC, and metal. The product also stands up well to direct exposure to UV rays, making it a perfect option for use around outdoor windows.

Steps on how to seal a window

So, how do you seal a window? Myron Ferguson follows the steps below.   

1. Cleaning and drying the work area: Never apply insulating foam sealant over a dirty surface. Create a strong and durable seal by cleaning and drying the work area first. If you are sealing a window that has been in place for a while, clear away any accumulated dirt or dust.

Expanding foam should not be applied over wet surfaces. Be sure to check whether the surface is dry. Any wetness should be addressed before you get the project underway.

2. Creating space for the foam: Expanding foam should be used on gaps at least ¼ inches wide. The canned spray foam application process becomes harder if the gap around the window frame is too narrow. Myron overcomes this challenge by creating a sizable groove around the window frame. To achieve this, he uses a utility knife to trim away bits of drywall.

By creating this narrow groove, Myron ensures that the end of the spray foam tube reaches deep into the cavity.

Myron Ferguson trims along the drywall edge.

3. Applying expanding foam: With the groove around the window frame clear, Myron moves to the next step of the window sealing process, applying Loctite Tite Foam Window & Door. Myron creates an air-tight seal by pushing the tube deep into the gap. He then starts spraying the foam slowly along the groove. This forces the foam deep into the crevice and covers the gap completely.

Spray insulating foam sealant into gaps until some protrudes outward. You can reinforce the seal by making a second pass over sections with a thin layer of foam.

Myron Ferguson carefully applies expanding spray foam around the perimeter of a window.

4. Trim excess foam: Insulating foam sealant tends to expand a lot. As such, you will likely spot the foam protruding outward from the gaps in which it's applied. Wiping off excess expanding foam can be messy. However, Myron has an easy fix. First, he leaves the foam to cure. Afterward, he uses a utility knife to trim the foam down to the level of the wall surface. This helps him achieve a neat finish.

Loctite Tite Foam Window & Door expands quite a lot. However, it does not exert too much pressure on the window jamb. This prevents any warping that might prevent the window from opening or closing properly.

Myron Ferguson cuts away excess spray foam.

5. Enjoy the benefits of properly sealed windows: Expanding spray foam is great for sealing gaps around windows. Myron Ferguson uses Loctite Tite Foam Window & Door to seal all gaps along the perimeter of windows. The foam is designed to create a long-lasting air-tight seal without exerting excess pressure on the jamb.

After you seal a drafty window, you can expect the following benefits:

  • Improved energy efficiency
  • Enhanced indoor comfort due to the elimination of air drafts
  • Better noise insulation
  • A flexible seal that is guaranteed to remain in place even with minor structural movements


To ensure that you enjoy all of these benefits, follow our detailed guide on how to seal windows for winter.

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