Crawlspace encapsulation

What this covers

Crawlspace encapsulation seals the dirt floor and foundation walls of a crawlspace with a heavy reinforced vapor barrier, closes the vents, and dries the air with a dehumidifier so the space stays dry. Before the liner goes down, the company removes debris and wet insulation, deals with standing water through a drain or sump, and treats or removes mold. The barrier is overlapped, taped at every seam and sealed to the walls and piers, and the dehumidifier drains to the sump or outside. A well-sealed crawlspace is dry enough to inspect in clean clothes, which is the simplest test of the work.

When to call

• Musty odors in the house, especially in humid weather or after rain.
• Sagging or wet insulation, rusted ductwork or condensation on pipes under the floor.
• Standing water or damp soil in the crawlspace, or cupped hardwood floors above it.
• Mold on joists found during a water damage repair or a home inspection.

What to expect

1. Clean outDebris, wet insulation and standing water are removed and any mold is treated.
2. DrainA perimeter drain or sump is added where water enters the space.
3. SealVapor barrier is laid, taped and sealed to walls and piers, and the vents are closed.
4. ConditionA dehumidifier is set and drained, and humidity is checked after it has run.