Crawl Space Water & Moisture

Frequently Asked Questions

What does crawl space encapsulation cost?

Full encapsulation typically costs $5,000–$15,000, driven by square footage, liner thickness, and whether drainage and a dehumidifier are included. A vapor barrier alone over dry soil runs from a few hundred dollars to about $4,000. Standing water or existing mold must be resolved first — encapsulating over either seals the problem in beneath the house.

What is the difference between crawl space waterproofing and encapsulation?

Waterproofing manages liquid water: drainage, a sump system, grading and gutters that move water out and keep it out. Encapsulation manages air and vapor: a sealed liner on the floor and walls, closed vents, and conditioned air. A chronically wet crawl space normally needs waterproofing first, because encapsulating over standing water traps it.

Why does my crawl space smell musty?

Bare soil under a house evaporates gallons of water upward every day, and that vapor condenses on cool joists and subfloor. Because crawl space air rises into the living space through the stack effect, a musty crawl space becomes a whole-house odour and air quality problem. The fix is a sealed vapor barrier plus humidity held under 55%.

What mil vapor barrier should a crawl space have?

6-mil poly meets many codes but tears during installation and every future crawl. 10–12 mil is the practical choice for a barrier you will occasionally access, and 20-mil reinforced liner is encapsulation grade. Rule of thumb: if anyone will ever crawl on it, use 12-mil or heavier.