Frequently Asked Questions

It costs more per square foot than fiberglass or cellulose, and it is hard to remove once it cures. It has to be mixed and sprayed correctly, and the house should be empty during application and for about a day after. Foaming the roof deck also changes how the attic works, so ductwork, gas appliances and ventilation need to be planned in.

The chemicals cost more than loose fill, the rig and protective gear are expensive, and the crew seals air leaks and insulates in the same step. HomeGuide puts installed foam at $1.50 to $5.00 per square foot versus $1.00 to $2.80 for blown-in. In return you get an air seal that loose fill does not provide on its own.

It depends on the spot. Open-cell works well on the underside of the roof deck and in interior walls. Closed-cell is the usual choice under floors over a damp crawl space, on crawl space walls and on metal buildings, because it resists water and slows vapor.

Alabama's amended energy code calls for R-30 in ceilings of new homes in Zone 3. The Department of Energy recommends R-49 to R-60 for an uninsulated Zone 3 attic, or adding R-38 to R-49 over 3 to 4 inches already in place. We measure what you have and quote to a target R-value.

In a humid climate, a vented crawl space with fiberglass batts under the floor often ends up damp, with sagging insulation. Closing the crawl space and insulating its walls, or spraying closed-cell foam under the floor, usually holds up better. We check drainage, grading and ductwork first, since standing water has to be fixed before either option.

Home centers sell small foam kits and cans for gaps and small areas. A whole attic, crawl space or wall system takes a heated, two-part rig and a trained crew so the foam mixes and cures correctly. For large areas, get a written quote from an installer.

Several chemical companies make two-part spray foam systems for installers, and each has its own open-cell and closed-cell products. What matters more for you is that the product is listed for the use, sprayed at the right thickness and covered by the required thermal or ignition barrier where code calls for one.

HomeGuide advises planning on at least 24 hours away after spraying, and the manufacturer's data sheet sets the exact re-entry time. We tell you the timing before the job so you can plan.

It can make a leak harder to spot, which is why we check the roof decking for stains and soft spots first. If we see signs of a leak, it should be repaired before any foam goes on.

Foam has to bond to a clean surface, so it goes on framing, decking or concrete, not over batts. Old material in the way usually comes out first, and that cost shows up as its own line on the quote.

For many houses with damp crawl spaces, yes, because it stops the source of the moisture instead of fighting it. It is not worth it until standing water and drainage problems are fixed. We tell you if your crawl space needs water work first.

A sealed crawl space needs some way to keep its air dry, and in a humid climate that is often a dehumidifier or a small supply of conditioned air from the HVAC system. We go over the options when we quote.

Batts under a floor absorb moisture from humid crawl space air, get heavy and sag off their supports. Once wet, they insulate poorly and can hold mold. They usually need to come out before the space is fixed.

Sometimes, but combustion air has to be handled correctly, and sometimes the better choice is foaming the floor and leaving the crawl space vented. We look at the equipment before recommending either.

The state's amended code lists R-30 for new-home ceilings in Zone 3, and the Department of Energy recommends R-49 to R-60 for an uninsulated Zone 3 attic. For blown cellulose or fiberglass that usually means well over a foot of depth. We quote to a stated R-value so you can check it.

A radiant barrier reduces heat radiating from the roof, but it does not stop air leaking from the attic into the house and it is not a replacement for insulation depth. Sealing and proper insulation come first.

Often the problem is the kneewalls and the floor between the room and the attic, not the main attic floor. Those spots need sealing and insulation of their own, which is why we look at the room from both sides.

Not if it is dry and clean. Old insulation that is wet, moldy or full of rodent droppings should come out, and sometimes it has to come out so we can reach the leaks underneath.

Yes. Dense-pack cellulose or fiberglass can be blown into closed walls through small holes that get plugged and patched. Some installers also use injection foam. Spray foam in its usual form needs open walls.

In a typical 2x4 wall, open-cell fills the cavity at lower cost and comes in near R-13 at full depth, using HomeGuide's R-3.5 to R-3.7 per inch. Closed-cell is worth it where you want the added strength or vapor control, such as walls next to a garage or below grade.

Often, but not always, since some owners added insulation over the years. We check a few cavities before quoting so the price reflects what is actually there.

Filled cavities do reduce sound, especially open-cell foam or dense-pack. Windows and doors are usually the weakest point for noise, so we set expectations honestly.

For stopping condensation, a modest layer of closed-cell foam often does it. For a shop you plan to air condition, more thickness pays back. We quote the thickness for each surface in writing.

Foam needs to bond directly to the steel to stop condensation. Old blanket insulation is usually removed first, especially if it is wet or torn.

Yes, closed-cell foam on the underside of the roof keeps humid air from reaching the cold steel, which is what causes the drip. Leaks at fasteners or seams still need to be fixed separately.

Rules vary by city and county and by how the building is used. Call your local building office before work starts; we can tell you what we know about the use you describe.

Signs include a musty or animal odor, visible droppings or nesting, stains from a past roof leak, batts sagging from a crawl space floor, or insulation that is matted flat. We check and tell you whether removal is needed or a top-up will do.

Vacuum removal of loose fill sends the material through a hose to bags outside, so very little dust reaches the house. We still cover the path and seal off the work area.

Vermiculite can contain asbestos, so it should be tested before it is disturbed. If it tests positive, a licensed abatement contractor handles removal before any new insulation goes in.

Yes. Once the old material is out, we can foam the roof deck or the crawl space floor, or seal and blow new loose fill, depending on the space.