Do 1 Thing ENERGY STAR: Find the Savings Under Your Feet by Sealing and Insulating Your Basement or Crawlspace


Basement and Crawl Space

By: Doug Anderson

This week EPA invites you to “Do 1 Thing ENERGY STAR,” by sealing and insulating your home. This blog post is the fifth in a five part series from ENERGY STAR’s home envelope expert Doug Anderson about the benefits of sealing and insulating your home, and how you can get started this fall.

In the last two blogs, I talked about taking steps to seal and insulate your attic to get your home ready for the winter. Second to the attic, the next best way to prepare for chilly winter weather and start saving energy is by sealing and insulating your basement or crawlspace.

Deciding whether to do it yourself or hire a contractor

If your basement or crawlspace is accessible and not too difficult to move around in, this may be a good do-it-yourself (DIY) project. However, it is probably best to call in a professional if your basement or crawlspace has any of these issues:

–       Is wet or damp

–       Has pest infestations (bugs/rodents/snakes)

–       Is very moldy

–       Has strong smells or odors

–       There are loose or dangling ducts/pipes/wires

–       There are foundation problems (such as cracks)

The good news is that there are many qualified contractors that can help you address these issues.

Sealing your basement or crawlspace

If you have decided to make this a DIY project, the first thing to do is inspect your basement or crawlspace for air leaks in common locations. Start sealing any gaps or cracks in exterior walls using long lasting, flexible, indoor/outdoor caulk for any gaps or cracks ¼ inch or less. Larger holes (more than 1/4 inch) in masonry that lead outside can be filled with spray foam-in-a-can and sealed outdoors with masonry caulk or a small amount of cement so the hole is covered and the foam is not exposed to the outdoors.  Chimneys, furnace flues, water heater flues, or dryer flues can all get very hot and require metal flashing and high temperature caulk to properly seal.

Next, seal the rim joist (the wood that sits on top of the foundation wall) as described here, and finish by sealing any remaining holes and cracks to make an airtight space.

Safe Sealing

As mentioned in Blog Post#3, before and after sealing your home, have a heating and cooling technician check your combustion appliances (gas- or oil-fired furnace, water heater, and dryer) for proper venting.  This is called combustion safety testing.  The testing is easy, but should be done by a professional contractor who can sign-off that the systems are working properly.

Also, in certain parts of the country, sealing may trap dangerous indoor air pollutants (like radon) in your home.  Visit the EPA website on radon here for more information.  You can do radon testing yourself for a low cost or hire a professional contractor to conduct tests and discuss solutions if they find problems.  The tests are easy and can give you peace-of-mind.

Additional information on achieving good indoor air quality and proper ventilation in your home can be found here.

Insulating your basement or crawlspace

Insulating basement walls yourself needs to be done carefully and with products that are designed to handle some moisture.  Rigid foam boards and spray foam have been shown to work well for this application because they are less susceptible to moisture issues.  For details on insulating basement walls, visit this technical document for guidance.

Before adding insulation to crawlspaces yourself, you will need to decide whether to insulate the crawlspace ceiling or the crawlspace walls.  Again, in this application it is recommended that you use products that are designed to handle some moisture.  For details on sealing and insulating crawlspace walls check out this technical document  or this technical document for guidance.

Learn More

Visit the newly updated Seal and Insulate with ENERGY STAR website for more detailed information on how to seal and insulate your basement or crawlspace.

We hope you have enjoyed EPA’s five part series on how to improve your home envelope for the winter. Do 1 Thing ENERGY STAR this week! Start sealing and insulating your home and enjoy comfort and energy savings for years to come!

Doug Anderson is an ENERGY STAR Project Manager and has been with EPA for 13 years. He works on issues related to the home envelope, including insulation products and energy efficient residential windows.

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