Crawl Space Encapsulation in Linden, TN

Perry County is shaped by two rivers, the Buffalo and the Tennessee, and by the ridges and valleys that feed their tributaries. The bottomland here was famously productive, which is exactly why people settled it. It is also exactly the kind of ground that stays damp under a house. Bottomland holds water the way ridge ground never does.

A county seat incorporated in 1850 has buildings from nearly every decade since, and a good number of them were built when a crawl space meant bare earth, a few vents cut into the foundation wall, and a layer of fibreglass batts stuffed between the floor joists. It does not work well here.

Those open vents were supposed to let damp air out. In Perry County's humid months they do the opposite. Warm outside air comes in, hits the cooler surfaces under the house, and the moisture condenses on joists, ductwork and the underside of the floor.

The terrain adds a second problem. Plenty of crawl spaces we open in this part of Tennessee are dry at the front wall and wet at the back, because the lot falls away toward a tributary hollow.

The liner. The floor and the walls of the crawl space get covered with a heavy reinforced polyethylene liner, overlapped and taped at every seam and mechanically fastened and sealed at the walls and around every pier. The goal is a continuous membrane between the ground and the house.

Sealing the vents and the rim. The foundation vents get closed off and sealed. The rim joist, where the floor framing meets the foundation wall, is one of the leakiest parts of any house, and it gets sealed and insulated, usually with closed-cell spray foam. That stops the outside air path that vents used to invite in.

Drainage and sump where the ground demands it. If water is actively entering the crawl space, a liner laid over the top of it is not a fix. Where groundwater is a factor, and on valley floor lots in Perry County it often is, we address it first with interior drainage and a sump pump that moves the water out before it ever reaches the liner.

Conditioning the air. Once the space is sealed it needs its moisture managed permanently. Depending on the house that means a dedicated dehumidifier sized to the space, or a controlled supply of conditioned air from the house system.

• Homes on bottomland or valley floor lots. Ground moisture is constant here. These houses benefit the most and the fastest.
• Older county seat housing stock. If the house predates sealed crawl space practice by decades, the joists have been breathing river valley humidity the whole time.
• Houses with cupped floors or a musty first floor. Both are moisture symptoms, and both usually trace back under the house rather than into it.
• Crawl spaces with fallen fibreglass. Damp batts sag and drop. Once they are on the ground they are doing nothing except holding moisture against the wood.
• Sloped lots with a wet low corner. If one end of your crawl space stays muddy, drainage plus a liner solves it properly.

The other failure is skipping the diagnosis. We look at the whole space first, tell you what we found, and put the scope in writing so you can see what each step is for.

You can also read about our full crawl space encapsulation service, our residential spray foam work, and the complete service area.