Spray Foam Insulation Services in Chattanooga, TN

Open-cell and closed-cell foam: what each does

Spray polyurethane foam comes in two main types. Both seal air leaks, but they behave differently.

• Open-cell foam is soft and spongy, expands a lot, and fills odd shapes well. It insulates at about R-3.5 to R-3.8 per inch and lets some water vapor pass. It is often used on the underside of roof decks and in interior walls for sound.
• Closed-cell foam is dense and rigid. It insulates at about R-6 to R-7 per inch, adds stiffness to what it sticks to, and at typical thicknesses slows water vapor enough to act as a vapor retarder. It is the usual choice for rim joists, crawl walls, metal buildings and tight spaces.

For most attics, either can work. Closed-cell gets more R-value in less space; open-cell costs less per square foot for the same depth. Our open-cell and closed-cell pages go deeper.

Crawl space and rim joist foam

Much of greater Chattanooga is built over crawl spaces and basements. The rim joist, the framing that sits on the foundation, leaks air all the way around the house. Closed-cell foam is the most effective way to seal it. It is often one of the best-value insulation jobs in a house.

In crawl spaces, foam goes on the foundation walls when the crawl is being sealed. That only works if water is under control first: gutters and grading fixed, any standing water drained, and a vapor barrier on the ground. Foam does not fix a wet crawl. When those pieces are in place, wall foam keeps the crawl closer to house temperature, which makes the floor above warmer in winter and keeps ducts from sweating in summer. See humidity, mold and spray foam.

Walls, kneewalls and bonus rooms

In new construction, additions and remodels with open walls, foam fills the stud bays and seals around outlets and framing. In finished attic rooms, the kneewalls and the sloped ceilings are the weak spots. Foam on the back of kneewalls, or on the roof deck behind them, can turn a room that is unusable in August into one you can sleep in. See wall and kneewall foam.

Garages, workshops and metal buildings

Rooms over garages often have a garage ceiling with poor insulation, making the room above hot in summer and cold in winter. Foam on the garage ceiling helps. Pole barns and metal shops around Soddy-Daisy, Ooltewah and north Georgia have a different problem: on cool nights, metal roof panels drop below the dew point and drip water on everything inside. Closed-cell foam on the panels stops that and insulates at the same time. See garage and shop foam.

What affects the price

• Area and thickness. Foam is priced by the board foot, which is one square foot one inch thick.
• Open-cell or closed-cell. Closed-cell costs more per board foot but needs fewer inches for the same R-value.
• Prep. Removing old insulation, covering surfaces, and access work.
• Barriers. Ignition barrier coating or drywall where required.
• Access. Low roofs, tight attics and crawl spaces take longer.

See our spray foam cost guide for Chattanooga for more detail. Your quote breaks out area, thickness and product.

Helpful details for a quote

• Approximate attic or crawl area, and roof pitch if you know it.
• Whether ductwork or HVAC equipment is in the attic or crawl.
• What insulation is there now.
• Any roof leaks or water in the crawl.
• The rooms that are hardest to keep comfortable.

Before and after: what homeowners usually notice

The first thing most people notice after an attic or rim joist project is fewer drafts and more even temperatures from room to room. Upstairs rooms cool down faster on summer afternoons. Floors over crawl spaces feel warmer in winter. The air conditioner runs in steadier cycles. Some homeowners notice less dust, because less outside air is being pulled in through gaps. How much your bills change depends on the house, how leaky it was, where the ducts are, and how you use your thermostat. We do not promise a specific savings number, but we will explain what we expect for your house and why.