Spray Foam Insulation in Birmingham, AL

Spray foam insulation goes on as a liquid and expands into a solid that fills every crack in the surface it touches. That makes it different from batts and loose fill, which slow heat but let air pass through them. In a Birmingham house, where summer air is hot and wet and the airport averages 70.4% relative humidity across the year, stopping that air is half the job. A foamed roof deck, crawl space wall or rim joist keeps the heat out and keeps humid air from reaching cool surfaces where it can condense.

Open cell vs closed cell

The two types of foam behave differently, and choosing the wrong one is the most common mistake we see.

Open-cell foam is light and soft to the touch. HomeGuide lists it at roughly R-3.5 to R-3.7 per inch. It expands a great deal, so it fills odd-shaped rafter bays and wall cavities well, and it costs less per square foot. It blocks air but lets some water vapor through, which can be useful under a roof deck because a small leak can dry out and show itself instead of hiding.

Closed-cell foam is dense and rigid, and HomeGuide puts it at roughly R-5 to R-7 per inch. At typical thickness it acts as a vapor retarder, it does not soak up water, and it adds some stiffness to what it is sprayed on. It costs more per square foot, so we use it where its strengths matter: crawl space walls, rim joists, the underside of floors over damp ground, metal buildings and any surface where moisture is a risk.

Where foam makes sense in Birmingham homes

• Under the roof deck, to bring a hot attic and the ductwork in it inside the insulated shell.
• Crawl space walls and rim joists, to close a damp, vented crawl space.
• Kneewalls and bonus rooms over garages, which run hot in summer because their framing leaves gaps that batts never fill.
• New walls and additions, where open studs make it easy to fill each cavity completely.
• Garages, shops and metal buildings, where closed-cell stops condensation dripping from cold steel on winter mornings.

Where foam is not the answer

We do not recommend foam everywhere. A wide, open attic floor with nothing in it but joists is usually cheaper to fix by air sealing the gaps and blowing cellulose or fiberglass to depth. Finished walls in older houses are often better filled with dense-pack cellulose through small holes than with injection foam. When two approaches would both work, the quote shows both prices.

The code and the targets

Alabama's amended 2015 energy code, as summarized by Alabama Power, lists R-30 for ceilings and R-13 for walls, and it treats R-20 of spray foam as meeting the ceiling requirement in a sealed, semi-conditioned attic. New houses must pass a blower door test under 5 air changes per hour at 50 pascals, and foam is one of the most direct ways to get there. Our quote lists the foam type and thickness for each area so you can see the R-value you are paying for.

Safety during and after the job

Spray foam is mixed on site from two components, and the fumes while it cures are the reason everyone else stays out. HomeGuide advises planning to be out of the house for at least 24 hours. We close off the work area, ventilate it and cover nearby surfaces. Foam left exposed inside living space or in some attics needs a thermal or ignition barrier depending on the product and the location, and we explain what applies to your house before we start.

Tell us which parts of the house bother you most, and we will look at them and price each area separately. Get a free estimate