Spray Foam Insulation in Decatur, AL

Spray foam insulation in Decatur earns its keep in the places where heat and humidity get into a house: the roofline, the crawl space, the rim joist and the walls of shops and metal buildings. It goes on as a liquid, expands to fill gaps and cures in place, so one layer insulates and stops air leaks. That air seal matters as much as the R-value in a city where Wikipedia's climate normals put July highs near 90F and annual rain near 50 inches. Two kinds of foam do two different jobs, and choosing between them is the first decision on every project.

Closed cell vs open cell

Closed-cell foam cures hard and dense. HomeGuide rates it at R-5 to R-7 per inch. At typical thickness it slows water vapor, does not soak up water, and stiffens the surface it bonds to. Open-cell foam cures soft and light, expands much more, and rates R-3.5 to R-3.7 per inch. It seals air very well and dampens sound, but water vapor can pass through it.

In the Tennessee Valley that points closed-cell toward the damp spots: crawl space walls, rim joists, the underside of floors over wet ground, and metal roofs and walls where condensation is the main problem. Open-cell suits the underside of a roof deck when the goal is a sealed, conditioned attic, interior walls where sound is the issue, and above-grade cavities in additions and bonus rooms.

Sealed attics and attic ductwork

Many Decatur-area homes have the air handler and ductwork in the attic. In August that attic can be far hotter than the outdoors, and every duct leak or thin spot in the duct wrap pulls that heat into the house. One fix is to spray foam under the roof deck and on the gable walls, which brings the attic inside the insulated space so the ducts sit in milder air. The other is to leave the attic vented, seal the ceiling below it, seal the ducts, and blow insulation to depth on the floor. Both can work. The right pick depends on how much ductwork is up there, the roof's condition and the budget, and we price both when both make sense.

What code and ENERGY STAR ask for

Summaries of Alabama's amended 2015 IECC-based code list Climate Zone 3 targets of R-30 for ceilings, R-20 or R-13 plus R-5 continuous for wood-frame walls, R-19 for floors and R-13 or R-5 continuous for crawl space walls. In a 2x4 wall, closed-cell foam reaches a strong R-value in two to three inches. On a roof deck, open-cell is usually sprayed thicker to reach the target. We write the planned thickness and target R-value on the quote so you can check it.

Where foam is not the answer

Foam does not fix a leak. If a roof, plumbing line or foundation is letting water in, that gets repaired first or foam will hide the damage. Foam also should not go over old knob-and-tube wiring or vermiculite that may contain asbestos until those are checked. And on a big, open attic floor with an easy-to-seal ceiling, blown-in insulation is usually the cheaper way to reach R-38 or more. We tell you when that applies.

Getting ready and getting back in

The spraying itself goes quickly; the prep takes longer. We cover floors and belongings, mask windows, outlets and fixtures, and set up ventilation. HomeGuide advises leaving the house for at least 24 hours while foam cures. For a detached shop or garage, the house may not be affected at all. Once foam cures it does not settle, so the thickness we leave is the thickness you keep.

Tell us what you want to fix: a hot bonus room, a damp crawl space, a shop that drips. We will look, explain where foam pays and where it does not, and send a written price. Get a free estimate