Crawl Space Encapsulation in Burns, TN

A vented crawl space in Middle Tennessee is not a dry crawl space. The vents let in warm, humid air all summer, that air condenses on the cooler surfaces under the house, and the fibreglass batts between the floor joists soak it up until they sag and fall. Then you have cold floors in January, a musty smell in July, and insulation lying on the dirt.

County geography pushes the same direction. Dickson County is bordered on the northeast by the Cumberland River, and the Harpeth runs along its eastern border. The ground between those drainages is rolling, and the creek bottoms and hollows hold moisture. Ground near the Yellow Creek and Cumberland Furnace bottoms stays damp long after rain. A crawl space on that kind of lot takes on water from below and humid air from the vents at the same time. Encapsulation deals with both.

Because we are based here, we also get called to crawl spaces that were half done years ago: a thin liner never sealed at the seams, vents still open, no conditioning. That is not an encapsulation, it is a plastic sheet.

The liner is the foundation of it. A heavy reinforced membrane covers the entire floor, runs up the foundation walls and wraps the piers. Every seam is overlapped and taped, and the edges are sealed to the wall. Thin hardware store plastic tears under foot traffic and stops being a vapour barrier the first time someone crawls across it.

Sealing comes next. The foundation vents are closed and sealed, because the point is to stop treating the crawl space as outdoor space. Gaps at the rim joist, plumbing penetrations and the access opening get sealed too. Closed-cell spray foam earns its keep here: it seals and insulates the rim joist in one pass, which is why our spray foam insulation work and our encapsulation work overlap constantly.

Drainage comes first if the space takes on bulk water, because a liner over an active water problem just hides it. Once the space is dry and sealed, it gets conditioned: either a small amount of conditioned air from the house system or a dehumidifier sized to the space. That keeps the humidity down through a Tennessee summer.

• Falling or missing floor insulation. If the batts are on the ground, the crawl space has a moisture problem, and new batts will end up the same way.
• Musty smells inside the house. A large share of the air on the ground floor comes up from below. What the crawl space smells like, the house smells like.
• Cold floors along the SR 47 corridor. Older homes on vented crawl spaces lose heat straight through the floor every winter.
• Lots toward the creek bottoms and low ground. Soil moisture evaporates upward into the joists all year unless a liner stops it.
• Homes about to be sold or bought. A wet, mouldy crawl space shows up on every inspection report. A sealed, conditioned one is a selling point.

The other half is doing the steps in the right order. Liner before drainage is wrong. Sealing vents over standing water is wrong. Conditioning a space still open to the outside is wrong. We crawl the whole space before we quote it, so the quote is based on what is actually under your house.

See our full crawl space encapsulation service or the complete service area.