Frequently Asked Questions

HomeGuide's 2026 range is $1.50 to $5.00 per square foot installed, depending on open or closed cell and thickness. Small jobs often hit a $1,000 to $2,000+ minimum. We give you a written price after measuring.

At HomeGuide's per-square-foot range, 2,000 square feet of foam would run roughly $3,000 to $10,000 before access and prep. Whole-house figures run $8,000 to $20,000 (HomeGuide) and $10,000 to $30,000 (Fixr). Your house gets its own written quote.

Mostly because of bad installs and hidden problems: foam covering a roof leak, odor from poor curing, or foam on sills that blocks termite inspection. On the Coast, termite access is a real concern. A careful install with records addresses most of it.

Blown-in insulation costs less per square foot: HomeGuide lists $1.00 to $2.80. Foam costs more because it also air seals. Sealing the attic floor and blowing in loose fill is often the value option when ducts are not in the attic.

If your air handler and ducts are in the attic, foam under the roof deck brings them into the conditioned space, which often helps a lot in this climate. If not, sealing and insulating the attic floor usually costs less.

Sealing cuts the humid outdoor air leaking in, which helps the air conditioner control moisture. A tight house still needs working exhaust fans and properly sized AC.

Open cell is common under roof decks in hot-humid climates and costs less. Closed cell may be used where more R-value per inch is needed. We look at the roof first.

A tighter house needs working exhaust fans and properly sized AC. We look at ventilation during the visit.

Check with your pest control company. Some require inspection gaps or restrict foam near sills and foundations. We work around those requirements.

HomeGuide advises 24 hours or more.

It depends on the crawl space, flood risk and where your ducts are. We explain both and price them.

Batts absorb humidity and sag over time in a vented crawl. Closed-cell foam on the subfloor avoids that.

Yes, with closed-cell on the underside of the floor.

Often. Sealing out humid air and covering the ground cuts the moisture that causes them.

ENERGY STAR suggests R-49 for an uninsulated Zone 2 attic, or adding R-38 over 3 to 4 inches.

If ducts are not in the attic, sealed and blown-in is usually the better value. If they are, roof-deck foam may be worth it.

No. It can reduce radiant heat but does not replace insulation or air sealing.

Usually a day for sealing and blowing in.

Yes. Closed-cell foam keeps humid air off the steel so condensation cannot form.

Foam makes it practical. Size the AC to the insulated building.

It depends on use; we size it to your plan.

Yes, enclosed carports and garages too.

Soaked insulation should generally come out once the leak is fixed; it loses performance and can grow mold.

HomeAdvisor lists $1 to $2 per square foot and $600 to $1,200 for a typical job.

Yes, and replace them with closed-cell foam or new insulation.

It is bagged and hauled away.

With air sealing and enough depth, yes. It is the value option for an open attic floor.

HomeGuide lists $1.00 to $2.80 per square foot and $900 to $3,600 for an attic.

If it is dry, clean and not hiding leaks, yes.

Some. We install to account for it.