Spray Foam Insulation in Harrison, TN

Lakefront living on Highway 58

Harrison stretches along the east side of Chickamauga Lake north of Chattanooga, between the Highway 58 corridor and the water. Harrison Bay State Park, one of the oldest state parks in Tennessee, anchors the shoreline, and the coves and points around it are lined with houses that range from 1950s fishing cabins to 1970s and 1980s ranches to newer lake homes. Census Bureau estimates for the Harrison census area put the median build year at about 1979, with roughly half the homes older than that.

Living on the lake means living in the wettest air in the county. Chickamauga Lake is a constant source of water vapor, and homes near the shore see fog, dew and humidity levels above the already-high regional averages. Any insulation under the floor of a Harrison lake house has to be a material that does not absorb water.

Piers, crawl spaces and the floor system

Older lake houses in Harrison often sit on block piers or a low, open crawl space, sometimes with the floor joists visible from the yard. Fiberglass batts under those floors are wet, sagging and often gone. The repair is closed-cell foam sprayed directly to the underside of the floor system, which seals the floor, insulates it and shrugs off the lake air. On houses with a full block crawl space, encapsulation with foam on the walls and rim joist, a sealed vapor barrier and a dehumidifier is the more complete solution.

Older cabins that have been added onto over the years tend to have several different foundation types under one roof: a crawl space under the original, a slab under a 1980s addition, piers under a porch that became a room. Foam handles the transitions between them, which is where the air and moisture problems concentrate.

Ranches on the inland side

Away from the water, along Highway 58 and the roads toward Ooltewah and Birchwood, Harrison's housing is mostly ranches and split-levels from the 1970s and 1980s on vented block crawl spaces, with attics that hold ductwork and a few inches of old insulation. The work on those is the county standard: remove the failed batts, seal and foam the crawl space, seal the attic floor and bring it to R-38 or foam the roof deck to bring the ducts inside.

Harrison is unincorporated, so permits go through Hamilton County, and it is served by EPB, so the EPB and TVA EnergyRight rebates for attic insulation and air sealing may apply under the program's terms.