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Airtight basement sealing secrets!

5 tips for air sealing a basement to improve insulation

Air-sealing basement areas can be a simple but effective way of improving your home’s energy efficiency. You can achieve better insulation by following our detailed basement air sealing tips. They include suitable supplies and tricks to ensure effective and lasting results.

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Importance of air-sealing basement areas

The stack effect (or chimney effect) causes cold air to be drawn into your home through the basement. This occurs as hot air (generated by the furnace) rises through the house, escaping through leaks in the attic. In addition to contributing to higher energy consumption, the chimney effect also makes your home feel draftier.

You can solve this problem with the help of a top-quality sealer like Loctite Tite Foam Window & Door.

Practical tips on how to air seal a basement

Myron Ferguson, a drywall and building performance contractor, uses Loctite Tite Foam Window & Door to improve a structure’s overall insulation. Simplify your work and boost your chances of achieving the desired outcome by following these tips:  

1. Get the right tools and materials needed to seal a basement. Sealing a basement is a moderately challenging DIY project. To make your work easier, begin by assembling the necessary supplies. Some of the tools and materials used by Ferguson include:

When air sealing your basement, always start with the larger holes/openings before moving to the smaller ones. As a rule of thumb, professional-grade canned spray foam is a great option for larger gaps — bigger than a quarter of an inch. Consider caulking any gaps that are a quarter inch or smaller.  

2. Locate any openings that cause air leakage. Ferguson starts the project by looking for air leakage points. Some areas you might want to give extra attention to include the space between the basement door or window frames and concrete walls, natural gas, water and electric service penetrations, air vents leading outside, and rim joints.

Consider switching off lights in the basement and looking for daylight. This is a simple way of finding cracks or openings that allow outside air to leak into your house.

Myron Ferguson reaching for Loctite Tite Foam Window & Door

3. Prepare the work area. Make sure that you wear the necessary safety gear before you start using expanding foam. In addition to clearing the work area, Ferguson also puts on a pair of safety goggles and gloves before getting down to the air sealing work.

It is worth mentioning that spray foam does not adhere well to wet surfaces. Take the time to inspect the surface you intend to cover with spray foam — looking out for any wetness. You should not apply spray foam over surfaces with a moisture rating that exceeds 20% 

Myron Ferguson wearing safety goggles and gloves.

4. Apply spray foam along the gap between the door frame and the concrete wall. Myron Ferguson discovered that the perimeter of a door leading from the basement to a cold storage space hadn’t been air-sealed. He used Loctite Tite Foam Window & Door to address the issue. Using this product came with two important advantages:

  • The lower expansion foam does not push the door jambs inward. As such, the door could open and close as well as before.
  • The foam’s flexibility is a welcome feature given seasonal temperature changes. As Ferguson puts it, “Seasonal movements and temperature changes dramatically affect building materials.” In this project, he applied the foam between wood and concrete — two building materials with different expansion and contraction properties. Given these properties, the product’s flexible structure created a solid and well-balanced seal.

5. Use a caulk and spray foam combination to air seal rim joists. Often left uninsulated, rim joists are a common air leakage source in basements. Air leaks can occur in gaps between the subfloor and the rim joist, the mudsill and the rim joist, and the mudsill and top of the foundation wall.

To keep air from leaking through these gaps, consider caulking them using Loctite Polyseamseal ACWS first. Afterward, you can apply a layer of spray foam to reinforce the seal. 

Now that you have completed the project, you can start enjoying the benefits of a properly air-sealed basement. They include:

  • Lower cooling and heating costs
  • Even temperatures across the house
  • Reduced strain on the HVAC system
  • Noise reduction and improved soundproofing

Products used

  • loctite polyseamseal acws white 10oz cartridge
    Loctite Polyseamseal ACWS

    Provides a flexible, weather resistant seal. Paintable in 30 minutes.

  • loctite tite foam window door 12oz can
    Loctite Tite Foam Window & Door

    Specialized formula will not bow windows or doors

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