Last updated: October 2026 · Cost figures are national reference ranges from published industry sources, not quotes.

Crawl spaces are mold factories: dark, damp, and rarely inspected. Mold remediation alone runs roughly $500–$2,000 (HomeAdvisor 2026) — but remediation without fixing the dampness is temporary. Encapsulation (vapor barrier + sealed vents + dehumidification) is the permanent fix and the premium upsell, typically $5,000–$15,000+. Together they're the highest-ticket residential mold scope there is.

Cost breakdown

Scope	Typical range	Notes
Mold remediation only	$500–$2,000	Cleanup without moisture control — expect recurrence in damp climates.
Vapor barrier alone	$1,000–$4,000	Heavy-mil liner on the ground; the minimum credible moisture step (2026 industry data).
Full encapsulation	$5,000–$15,000+	Barrier + sealed vents + conditioned air or dehumidifier; the permanent solution.
Crawl-space dehumidifier	$1,000–$3,000 installed	Required in most encapsulations to hold humidity below 60%.
Drainage / sump pump	$2,000–$6,000	If groundwater enters the crawl space, nothing else works until this does.

What moves the price

• Remediation-only vs. full encapsulation — a 3x–10x price difference for a permanent vs. temporary fix
• Crawl-space size, height, and access — tight, debris-filled crawls cost more in labor
• Whether groundwater enters (drainage first) or it's just humidity (barrier + dehumidifier)
• Existing damage to floor joists, subfloor, or insulation from long-term moisture

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