Wall Insulation in Birmingham, AL

Wall insulation is easy to overlook because you cannot see it. Many older Birmingham houses were built when insulating walls was not standard, and Point2Homes' summary of 2019-2023 Census survey data shows 18.3% of the city's homes date to 1939 or earlier and roughly 43% to before 1960. A house from that era may have plaster walls with empty cavities, or insulation that has slumped to the bottom of each bay. Those walls let in summer heat and let out winter warmth, and they often feel warm to the touch on an August afternoon.

Finished walls: filling from outside or inside

For walls that are already closed up, the usual approach is to drill a small hole in each stud bay, from outside under the siding or from inside through the plaster or drywall, and fill the cavity. Dense-pack cellulose is blown in at high density so it fills the cavity, resists settling and slows air movement. Injection foam is a low-expansion foam made for closed cavities. Both work; dense-pack is usually the lower-cost option. The holes are plugged and patched afterward, and on brick veneer houses we often work from inside.

New walls and additions

When studs are open, during a remodel, an addition or new construction, it is the easiest moment to insulate well. Alabama's amended 2015 code, as Alabama Power summarizes it, lists R-13 for walls. The Department of Energy's recommendation for a Zone 3 wall is R-20, or R-13 plus R-5 of continuous insulation. At HomeGuide's R-values per inch, open-cell foam filling a 3.5-inch 2x4 cavity reaches about R-12 to R-13, and closed-cell at the same depth reaches roughly R-17 or more, while also sealing the wiring and plumbing holes that batts leave open. We write the depth and R-value for each wall on the quote.

Walls between living space and attic

Some of the worst walls in a house are not exterior walls at all. Kneewalls behind bonus rooms and upstairs bedrooms, and walls between the house and an attached garage, often have batts that are loose or missing their backing. In summer they let attic heat straight into the room. We foam or re-insulate these walls and add a rigid backing where air has been washing through the batts.

Before we fill a wall

We check what is already in the cavity, look for knob-and-tube wiring in very old houses (which should be evaluated by an electrician before walls are filled), and look for signs of moisture from leaks or failed flashing. Filling a wall that gets wet from outside can trap the water. If we find a problem, we tell you before quoting.

Let us know how old the house is and which rooms feel worst, and we will check the walls and price the options. Get a free estimate