Frequently Asked Questions

It costs more per square foot than fiberglass or cellulose, it is hard to remove once cured, and it must be applied correctly to cure and smell right. You also need to stay out of the house for a while after spraying; HomeGuide suggests at least 24 hours. That is why we use foam where its air sealing and moisture resistance matter and blown-in insulation where they do not.

It depends on the part of the house. North Carolina code for the Triangle (Climate Zone 4A) calls for R-38 ceilings, and ENERGY STAR suggests R-49 to R-60 in an attic. Blown cellulose or fiberglass is usually the cheapest way to reach that depth on an open attic floor, while closed-cell foam suits crawl space walls and rim joists, and open-cell foam works well under roof decks and in bonus room walls.

HomeGuide lists $1.50 to $5.00 per square foot installed, with open-cell at the low end and closed-cell at the high end, or about $1,500 to $5,000 for 1,000 square feet. A crawl space runs about $2,000 to $4,000 in that guide. We give you a written price after measuring.

Neither is better everywhere. Closed-cell resists moisture and is our usual pick for crawl space walls and rim joists. Open-cell is softer, cheaper per inch of thickness and works well under the roof deck or in walls where it can expand into the cavity.

Many Durham crawl spaces pull in humid outside air through foundation vents all summer, and sagging fiberglass under the floor stops working once it gets damp. Sealing the crawl space with a ground liner and insulating the walls is one fix; repairing the floor insulation and vapor barrier is another. We look at drainage, wood moisture and your HVAC setup before recommending either.

Duke Energy lists an instant attic insulation rebate for single-family homes brought up to at least R-38, ranging from $0.25 to $0.31 per square foot. It requires a Home Energy Check and a contractor on Duke's approved list, so confirm eligibility with Duke before relying on it.

It is worth it where air sealing and moisture control matter: roof decks over attic ductwork, crawl space walls, rim joists and bonus rooms. On an open attic floor, blown-in insulation over sealed bypasses usually gives more R-value per dollar.

Foam does not feed mold, but trapping moisture can cause problems in any assembly. That is why we fix leaks and wet wood first and pick closed-cell foam where vapor is a concern.

Most single areas, like a crawl space or bonus room, take a day. Larger roof-deck jobs can take two. You will need to stay out of the house during spraying and for at least 24 hours afterward, per HomeGuide.

Several chemical companies make two-part spray foam systems for both open-cell and closed-cell foam. What matters more for you is the product chosen for each space, its listed R-value per inch, and its fire rating where foam is left exposed, and we put that information on the quote.

In a damp crawl space with ducts underneath, it often is, because it keeps humid summer air from condensing on the floor framing and ductwork. In a dry crawl space with a good ground cover, a floor insulation repair may be enough.

A sealed crawl space needs some way to stay dry. A dehumidifier is common; supplying a small amount of conditioned air is another option. We discuss which fits your house and HVAC setup.

Fiberglass batts absorb moisture in a humid crawl space, get heavy and drop. They also lose most of their value once they pull away from the subfloor. We remove the wet batts and fix the moisture source before replacing them.

Not until the water is handled. Grading, gutters, a drain or a sump may be needed first. Sealing over a wet crawl space traps the problem.

The 2018 North Carolina Energy Conservation Code calls for R-38 in ceilings in Climate Zone 4A. ENERGY STAR recommends R-60 for an uninsulated attic and R-49 added over 3 to 4 inches of existing insulation.

Only if it is wet, moldy, contaminated by rodents or in the way of air sealing. Dry, clean insulation can usually stay, with new insulation blown over the top after the bypasses are sealed.

Sealing and insulating the attic floor cuts heat coming down through the ceiling and stops cooled air leaking up. If the upstairs includes a bonus room with kneewalls, those walls usually need attention too.

Duke Energy lists an instant rebate for raising single-family attic insulation to at least R-38, applied by a Duke-approved contractor after a free Home Energy Check. Check with Duke that your account qualifies.

It is surrounded by attic and garage on most sides, and the kneewalls, sloped ceiling and floor are often poorly sealed. Fixing those surfaces usually helps more than turning down the thermostat.

You can, but it will run hard if the room still leaks. Sealing and insulating first lets a smaller unit do the job, or lets your existing system keep up.

Usually not. Most of the work happens from the side attics and the garage ceiling. Sloped ceilings sometimes need small access holes for dense-pack, which are patched afterward.

Most bonus rooms take one to two days, depending on the approach and how tight the side attics are.

On an open attic floor, blown-in over sealed bypasses usually gives more R-value per dollar. Foam is better for roof decks, crawl space walls and spaces where moisture or tight framing make loose fill a poor fit.

Dry, undisturbed loose fill keeps working for decades. It loses value when it gets wet, gets packed down by foot traffic or is disturbed by rodents.

Often, yes, by drilling small holes and dense-packing cellulose. We check for knob-and-tube wiring and blocking inside the walls first.

Some settling happens, more with cellulose. We blow to the settled depth the manufacturer lists for the target R-value.

Not usually. Dry, clean insulation can stay. Removal makes sense when it is wet, moldy, rodent-soiled or blocking air sealing or spray foam.

Vermiculite looks like grayish-brown or silvery pebbles, unlike fluffy fiberglass or gray cellulose. If you see it, do not disturb it; have it tested.

Most attics take a day. Crawl spaces vary with height and how much material is down there. Replacement can often happen the same day or the next.

Yes, but it is slow work since cured foam is bonded to the surface. HomeGuide lists $1.00 to $2.50 per square foot, and Fixr notes hand chipping can reach about $5.