Crawlspace Insulation: What You Need To Know

Crawlspace Insulation: What You Need To Know

Most people understandably don't want to spend a whole lot of time in the crawlspace under their house. Mold, fungus, bacteria, and sometimes even mushrooms often thrive in this area where it gets so damp and humid. There's good reason why kids think monsters live here.

But did you know crawlspaces were not always the dark and damp places that we think of today? In the past, they were more like small basements — dry and easy to access. Like basements of today, they allowed builders to easily access pipes and ducts that needed repairs.  

The way modern homes are constructed doesn't allow for moisture to escape crawlspaces as freely. Homeowners are using crawlspace insulation to reduce the amount of trapped moisture and prevent any growth in these areas.


Why are crawlspaces so damp?

Originally, crawlspaces were used in homes with wood floors. The open, breathable wood floor allowed moisture to escape easily and prevent mold from growing. Today, when non-porous building materials (like tile and linoleum) are used on floors, moisture evaporates from the soil and becomes trapped in the crawlspace below. Heat from the house turns these crawlspaces into humid breeding grounds for mold and fungus. 


Many homebuilders tried to improve crawlspace conditions by adding vents. By allowing outside air to circulate within the space, homebuilders hoped that they could dry the area and prevent fungus and mold. In some regions like Arizona, New Mexico, and Texas, vented crawl spaces were a success. The hot, dry climate in the Southwest means that moisture rarely gets trapped in a crawl space.

But vented crawl spaces are not a good solution everywhere. In the southern midwestern/eastern state, venting a crawl space actually made the problem worse: vented crawlspaces in these regions are more humid and breed more bacteria than insulated crawlspaces.


Prevent mold and mildew with Double Bubble Crawlspace Insulation 

Other builders advocate for conditioned/insulated crawlspaces. These areas have no vents and are sealed and insulated to prevent outside moisture from entering the crawlspace in the first place. Conditioned crawl spaces prevent mold and fungus growth in hot/humid climates in the American South and in damp climates like the Pacific Northwest.  

Home builders that use the conditioned method believe that the crawlspace area should be treated as part of the building envelope. Instead of insulating underneath the floor and on top of the crawlspace, builders insulate around the perimeter of the crawl space. Installing a protective barrier on the ground or slab prevents moisture from seeping into the crawl space.

An added bonus: conditioned crawl spaces can also cut down on energy leaks because heat does not escape through an un-insulated crawl space.  

EcoFoil® Double Bubble Insulation is an excellent choice for insulating crawlspaces. Unlike fiberglass insulation, EcoFoil® is does not allow the passage of moisture and resists growth of mold and other fungi. When installed on the bottom of 9.5" floor joists, you will benefit from an impressive R-17 of insulation value while simultaneously blocking moisture and other harmful vapor barriers.   

More Articles You May Like:

6 Steps to Winterize Your Greenhouse

Can Bubble Insulation Work in My Attic?

Installing Radiant Barriers: The Importance of Air Space

Joist Panning for Return Air Ducts

Insulating your crawlspace is the best option, no matter what climate you live in, to keep moisture and growth out. Contact our experts to learn more about crawlspace insulation by email or by calling 1-888-349-3645.

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