Crawl space encapsulation in Tupelo
Encapsulation shuts a damp crawl space off from muggy outdoor air and wet clay below. Here's what the work involves in Lee County.
An encapsulated crawl space is what the International Residential Code calls an unvented crawl space. Rather than relying on foundation vents, the space is closed off from the outdoors, the ground is covered with a continuous sealed liner, and some form of humidity control is added. That last part matters: sealing a crawl space without managing the moisture inside it can leave you with a closed box of damp air.
What does the code require?
Section R408.3 of the IRC lets you leave out foundation vents when the exposed earth is covered with a continuous Class I vapor retarder, with seams overlapped 6 inches and sealed or taped, and the edges carried at least 6 inches up the stem wall. It also requires one way of handling moisture: continuous exhaust at 1 cubic foot per minute for every 50 square feet of floor, a conditioned air supply at the same rate, or a dehumidifier that removes 70 pints a day for every 1,000 square feet. Tupelo's council voted to adopt the 2024 International Code Council codes, which include the residential code.
Why it suits Tupelo houses
Tupelo gets close to 58 inches of precipitation in a typical year, and the Black Belt clays under much of the area hold that water. DOE's Building America research found unvented, conditioned crawl spaces cut humidity by more than 20% in its studies, along with heating and cooling savings. A sealed crawl space also keeps out the humid summer air that makes ducts sweat.
Steps in a typical job
- Look first. Check for standing water, plumbing leaks, rotted wood, termite signs and the condition of the insulation.
- Handle liquid water. Gutters, grading, or an interior drain and sump. Sealing in a crawl space that floods only traps the water.
- Clear it out. Remove old plastic, fallen batts and construction debris.
- Seal the shell. Close vents, the access opening and gaps around pipes, wires and ducts.
- Install the liner. Seams overlapped and taped, run up the walls and wrapped around piers.
- Add moisture control. A dehumidifier, exhaust fan or small supply of conditioned air.
What affects the price?
- Square footage and how low the clearance is
- Liner thickness and how much wall and pier area gets covered
- Amount of old insulation and debris to haul out
- Drainage work needed before sealing
- The humidity-control equipment and any new electrical circuit
Every price comes from the crawl space company, after someone has actually been under your house. We don't quote prices, and any number you hear over the phone before an inspection is a rough guess at best.
Where we connect you with help
Common questions
Is encapsulation just a heavier vapor barrier?
No. A vapor barrier covers the ground. Encapsulation also closes the vents and adds humidity control, as IRC Section R408.3 lays out for unvented crawl spaces.
Can a crawl space that gets water be encapsulated?
Yes, but the water problem gets solved first or in the same job, usually with gutters, grading or an interior drain and sump.
Related services
More background: Tupelo crawl space guide.
Musty air, a bouncy floor or water under the house?
Call and we'll connect you with a crawl space company that works in Lee County.