Crawl space encapsulation
Encapsulation turns a damp, vented crawl space into a closed one that's kept dry. Here's what goes into it and what to ask.
An encapsulated crawl space is sealed off from the outdoor air and the bare ground. Instead of fighting South Georgia humidity with open vents, the space is closed up, covered with a continuous liner and dried with a dehumidifier or a small amount of conditioned air. Done right, the framing stays drier, the musty smell fades, and the ducts and floors above it aren't sitting in muggy air all summer.
What does an encapsulation job include?
- Inspection and cleanup. Old insulation, debris and torn plastic come out. Wet or damaged wood is noted for repair.
- Water first. Gutters, grading or an interior drain may come before any liner if water gets in.
- Sealing openings. Foundation vents, gaps and holes around pipes are closed, and the rim area may be sealed or insulated.
- The liner. A continuous vapor retarder covers the ground and runs up the walls, with overlapped, taped seams.
- Drying the air. A crawl space dehumidifier or a supply of conditioned air keeps humidity in check.
What does the code require?
The International Residential Code, which Georgia uses with amendments, sets out rules for unvented crawl spaces. Southface's Georgia energy code field guide says exposed earth must be covered by a continuous Class I vapor retarder, like 6-mil polyethylene, with sealed seams and the liner extended up the walls. Many companies use a thicker, reinforced liner because people crawl over it for years. If the walls are insulated, Georgia requires a 3-inch view strip below the floor joists so termite activity can still be inspected.
Questions to ask before you sign
- How will you deal with water before the liner goes in?
- How thick is the liner, and how are seams and edges sealed?
- What will dry the air, and who services it?
- Will the termite inspection strip be left open?
- What's warrantied, and for how long?
Pricing comes from the crawl space company, after someone has been under the house and measured it. We don't quote prices, and a number offered before anyone has looked at the space is only a guess.
Where we connect you with help
Common questions
Does encapsulation help with my power bill?
It can. DOE's Building America program measured 15 to 18 percent heating and cooling savings and humidity drops of more than 20 percent in homes with unvented, conditioned crawl spaces. Results vary by house.
Can I still get a termite inspection after encapsulation?
You should be able to. Georgia requires a 3-inch inspection strip below the joists when crawl space walls are insulated. Ask the installer how they'll keep piers and sills visible.
Related services
More background: Lowndes County crawl space guide.
Musty smell, droopy insulation or a floor that gives underfoot?
Call and a crawl space company that works in Lowndes County will take a look under the house.