Crawl Space Insulation: Best Practices to Energy Efficient Crawl Spaces

Creating Energy Efficient Crawl Spaces with Crawl Space Insulation

Properly insulating crawl spaces can help turn them into energy efficient crawl spaces, when combined with air sealing and moisture control. Crawl space insulation types depend on whether you have a ventilated or unventilated crawl space. Most crawl spaces are vented, as to prevent moisture issues - which is why the majority of building codes require vents in the first place. However, there are contractors and other building professionals who recognize that unventilated crawl spaces might be the better option for homes that are using proper drainage and moisture control techniques.

Simply put: in the winter, ventilation makes it difficult to keep your crawl space warm; and during the summer, the warm air brought into your crawl space through vents can lead to increased moisture levels and ultimately mold growth.

According to HouseLogic, "Even though hot air rises, homes lose heat in all directions. So besides insulating the top and sides of your house, you also need to insulate the bottom, where as much as 30% of energy loss can occur. As with the attic, you have two choices: Insulate under the bottom floor and treat the crawl space or basement as outdoor space, or insulate the walls and treat the area as indoor space. In that case, you would close off all exterior vents except those needed for combustion air or exhaust."

HouseLogic also points out that, "Though floor insulation is more common, wall insulation has many advantages, including cost-it takes about a third less material to insulate the walls of a 36-by-48-foot basement as to insulate the subfloor above. A key detail, not understood by all builders, is to place a layer of rigid foam insulation against the foundation to keep moisture from condensing against the cold walls. If you want to finish the basement, you can cover the foam with a stud wall, fill it with un-faced fiberglass insulation, and cover with drywall."

How Important is Crawl Space Insulation for Energy Efficient Crawl Spaces?

According to an article published by CertainTeed Home Institute, "Crawlspaces can cause problems if they are not properly insulated. For instance, some crawlspaces contain water pipes which can, when they experience severe temperature extremes, freeze and burst. Or they may contain uninsulated heating and air conditioning ducts which can waste costly energy. Insulating the crawlspace can help prevent this from occurring. Also, an uninsulated crawlspace can make the floors and temperatures in the home above it colder in winter weather and hotter in the summer, affecting the comfort of the homes inhabitants."

Energy Efficient Crawl Spaces for Unventilated Crawl Spaces Using Crawl Space Insulation

If you have crawl spaces that are not ventilated, the best practice to making them energy efficient crawl spaces is to seal and insulate your crawl space's foundation walls. For this type of crawl space insulation, you will need to:

• Seal and/or eliminate your crawl space's foundational vents.
• Seal any and all exterior wall air leaks during and after crawl space insulation construction.
• Make sure your furnaces and water heaters are equipped with power combustion systems.
• Install exterior and interior foam to make sure you have complete insulation coverage.
• Install a termite barrier between the joists and foundation wall. Make sure it covers the entire wall insulation and that it extends outside completely.
• Put a supply outlet in your crawl space.

Energy Efficient Crawl Spaces for Ventilated Crawl Spaces Using Crawl Space Insulation

Creating energy efficient crawl spaces for ventilated crawl spaces using crawl space insulation means you will need to:

• Seal all holes and leaks in the above floor to stop air from coming into the house.
• Use rolled fiberglass to insulate between your crawl space's floor joists, making sure to install it against the subfloor - tightly. Seal off all seams, being careful to keep wind away from the insulation while adequately supporting the insulation using a mechanical fastener to ensure it won't fall out of place.
• Cover up the fiberglass using a house wrap, or letting it face a vapor barrier.
• Use a polyethylene vapor retarder over dirt floors and tape and seal all the seams carefully. Be careful not to cover the plastic with anything can could puncture holes in it (think gravel).
• If you're considering a concrete slab, make sure the headroom of the crawl space is meeting local code requirements.

Looking for Other Ways to Turn Your Crawl Spaces into Energy Efficient Crawl Spaces?  

If you are experiencing mold in your crawlspace, there are several solutions you can look into for dealing with the moisture issue that led to the mold growth. Some solutions for dealing with crawl space moisture issues are as simple as installing a crawl space vapor barrier system, addressing the grade of your landscaping, or properly guttering rainwater away from the property; however, a crawl space service expert may be necessary to solve your issue.

AdvantaClean offers crawl space moisture control solutions:

• Crawl space inspection
• Moisture control products
• Crawl space insulation
• Crawl space vapor barrier
• Crawl space encapsulation - AdvantaSeal
• Controlling moisture and humidity in the home
• Black mold removal
• Drainage and sump pump installation - AdvantaDrain

More info? For more information about common places for moisture in your home, check out our related post: Crawlspace Moisture Problems.