Protect Your Home with Vapor Barriers from PNW Eco Insulation

Arlington and Everett average over 40 inches of rain per year. Without a vapor barrier, moisture from the soil rises into the crawl space and creates persistent humidity problems. A vapor barrier blocks ground moisture at the source and is one of the most important steps a homeowner in this region can take.

Crawl space moisture causes mold and mildew growth, wood rot in floor joists and framing, insulation failure, and musty odors throughout the home. It also attracts wood-destroying pests. In Bellevue, Redmond, Mill Creek, and Burlington, uncontrolled crawl space moisture is one of the leading causes of preventable structural damage.

A vapor barrier covers the full exposed soil floor and extends up foundation walls and around support piers. For most homes in Arlington, Burlington, Everett, Mill Creek, Bellevue, and Redmond, we recommend a 6-mil to 20-mil reinforced polyethylene barrier, with heavier material used where moisture exposure is highest.

Damp insulation can lose 40 percent or more of its thermal performance. A vapor barrier keeps ground moisture from reaching the insulation, allowing it to maintain its rated R-value. In Snohomish and King counties, where soil stays damp most of the year, a vapor barrier is what allows insulation to actually work as intended.

Damp crawl spaces make floors feel cold, raise indoor humidity, and can introduce mold spores and odors into living areas. Controlling crawl space moisture helps floors feel warmer in winter, reduces indoor humidity, and creates a noticeably cleaner living environment across all seasons in Western Washington.