Crawl Space Insulation

The right insulation can increase your comfort level, decrease your utility expenses, and help prevent mold and moisture damage.

Crawl space insulation is important. A number of comfort and energy problems are caused by inadequate or incorrect crawl space insulation.

Signs of crawl space insulation problems

Save now but pay later. Fiberglass batt insulation is inexpensive. But it doesn’t perform well or last long when installed between crawl space joists.

• The floor above the crawl space is unpleasantly cold in wintertime.
• During cold weather, you have to keep the heat going nearly all the time to be comfortable in rooms directly above the crawl space.
• Mice or other pests have taken up residence in fiberglass insulation installed between joists in the crawl space.
• Fiberglass batt insulation has fallen out of place from between floor joists in the crawl space.
• The crawl space smells moldy or has visible signs of mold.
• The crawl space is damp all the time.

Crawl space insulation done wrong: fiberglass batts installed between joists

The old-fashioned way to insulate a crawl space was to install fiberglass batt insulation between joists and vent the crawl space so outside air could circulate beneath the house.

Unfortunately, this combination usually leads to the problems listed above. Fiberglass insulation doesn’t respond well to the moist conditions that can be found in a crawl space.

The cotton-like material absorbs moisture, gets soggy, compresses and loses R-value. Fiberglass batts often end up on the crawl space floor in a soggy mess. The main advantage of fiberglass insulation –low cost—is totally negated when the material ceases to perform its main function.

Crawl space insulation done right: rigid foam panels installed against crawl space walls

Looking good & lasting long. Rigid foam insulation can’t be damaged by moisture and won’t degrade in appearance or R-value over time. In a crawl space, it’s usually installed against the interior face of foundation walls.

Rigid foam insulation performs much better than fiberglass in a crawl space. This type of insulation is manufactured in panels of different thicknesses. Installers cut the panels to fit against the interior face of crawl space foundation walls. Panels are secured with adhesive or mechanical fasteners.

Insulating a crawl space with rigid foam is often done as part of the crawl space encapsulation process –a treatment that building scientists recommend. Crawl space encapsulation effectively seals your crawl space off from the exterior, giving you control over the environment beneath your living space.

Although rigid foam insulation costs more than fiberglass insulation, it’s less expensive when you consider that you’ll never have to clean up or redo a mess of damaged, ineffective installation. Rigid foam will deliver the same performance and benefits in 15 years as it does on day #1.

Related Pages

• Insulation
• Garage Insulation
• Wall Cavity Insulation
• Radiant Barriers

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