Green Building: Encapsulation of Crawl Space
To encapsulate a crawl space or vent to the outside? This question is a common one, considering crawl spaces are a popular construction feature in American homes – thanks to their convenience and cost-effectiveness. While vented crawl spaces are relatively easier to construct, they can pose more harm than good in the long run.
What are the Shortcomings of Vented Crawl Spaces?
It’s a hub for pests and critters that are a health risk and may damage equipment parts or items stored there.
Moldy and musty air that can be circulated by the HVAC system and contribute to indoor air pollution.
Dampness can lead to high humidity in the living area.
Rather than increase the risk of indoor air pollution by venting to the outside, consider unvented crawl spaces.
Benefits of Encapsulating a Crawl Space
Green building standards advocate for encapsulation of a crawl space to address indoor and crawl space moisture problems. This process involves sealing vents, insulating surfaces, installing a vapor barrier, and creating a conditioned air space.
What are the Benefits of Encapsulated Crawl Spaces?
Green Building: Sealing and insulating a vented air space reduces heating and air conditioning needs significantly. According to recommendations by ENERGY STAR, basements or crawlspaces offer one the most significant energy-saving opportunity only second to the attic.
Indoor Air Quality: It improves indoor air quality in both the crawl space and the living area. This improvement is especially essential for homeowners with respiratory health problems such as asthma or allergies.
Durability: Mold and moisture can lead to structural damage of wooden framings on floor joists. Pests such as rats may also damage piping systems, electrical cables, and equipment in the crawl space.
Green Building Tip for Unvented Crawls Spaces
Are you planning to convert a vented crawl space into a more energy-efficient unvented crawl space? Here are a few water-management tips to address moisture-related issues.
Consider the weather conditions and specific climate. It's critical to consider the weather conditions and climate of the region before encapsulating crawl spaces. Always check the IECC Climate Zone Map.
Add a vapor barrier. Cover the crawl space and foundation walls with a polythene sheet (6-mil or thicker) and secure it with mechanical fasteners, wood furring strips, or fiberglass mesh tape. Overlap and tape any seams in the vapor barrier at least 6 inches. Some contractors may install a concrete slab over the vapor barrier to increase its durability.
Install exhaust fans. The fans will pull moldy and possibly contaminated air from the crawl space. Conditioning the air help improve the indoor air quality and promote a dry crawl space.
Sump pumps. Low-lying areas should be fitted with sump dumps to carry away excess water from storms or leaks in the foundation wall. The sump dumps should have tight-fitting lids, gaskets, and a 2-3 feet deep plastic pit with holes to drain the water efficiently.
Slope the ground away from the building for drainage. Driveways, sidewalks, and concrete patios should slope away from the structure to reduce the risk of bulk intrusion. Also, consider installing downspouts, gutters, and drainage pipes to carry away rainwater.
For more information on the encapsulation of crawl spaces and green buildings, contact Grayson Homes at 919-578-6222.