Frequently Asked Questions

At HomeGuide's $1.50 to $5.00 per square foot of foam surface, the total depends on how many square feet of walls, roof or floor get sprayed, not the floor area of the house. HomeGuide's whole-house range is $8,000 to $20,000. We measure and give you a written number.

HomeGuide lists $1.50 to $3.50 per square foot for open-cell and $3.00 to $5.00 for closed-cell, installed. Small jobs often carry a minimum of $1,000 to $2,000 or more.

Other insulation is cheaper per square foot. Blown-in runs about $1.00 to $2.80 per square foot by HomeGuide's figures. Foam costs more because it also seals air and, as closed-cell, slows moisture.

Mostly because of poor installs: foam sprayed over roof leaks, on roof decks without a moisture plan, or too thick in one pass. Some inspectors and lenders want to see roof framing. Installed in the right places, and documented, foam is a sound choice.

Yes, for comfort as much as for bills. Uninsulated floors and walls feel cold on foggy mornings, and attics heat up on warm afternoons. Sealing and insulating evens that out.

ENERGY STAR recommends R-49 for an uninsulated attic in zone 3, or adding R-38 over three to four inches. Alameda County is listed in climate zone 3C.

Yes, if the crawl space is accessible. Insulation between the floor joists, supported properly, makes floors noticeably warmer. ENERGY STAR recommends R-19 for floors in zone 3.

It depends on the project. ADUs, additions and remodels usually need permits and must meet Title 24. Simple insulation retrofits may not. Check with your city's building department; we can help you figure out what applies.

In the right places: tight cathedral ceilings, remodel walls, additions, ADUs and sound control. On a wide attic floor, sealing plus blown-in is usually better value.

Open-cell foam absorbs sound and seals the gaps sound travels through, so it noticeably cuts street and household noise.

Standard spray foam needs open framing. For closed walls we use dense-pack or injected methods.

After it cures and the re-entry period passes, it is an inert solid. We follow product ventilation and re-entry instructions.

Foam can help meet Title 24 insulation and air sealing requirements. The plans set the R-values; we install to them.

If it is dry, clean and free of rodent contamination, yes; we add on top. If not, it should come out first.

An electrician must check or replace it before insulation covers it.

Yes. A sealed, deep attic keeps afternoon heat from pushing into the rooms below.

Usually, by working from the hatch with hoses. Some areas may need foam on the roof deck instead.

Usually, yes, especially on cold mornings. Floors over vented crawl spaces are a big source of discomfort in older houses.

It was not supported well, or it got damp and heavy. It should be removed and replaced with properly supported insulation.

If the soil is damp, a vapor barrier helps keep moisture out of the crawl space. We check on the visit.

If you are planning it, yes. Insulate after bolting and bracing are done.

Yes, with dense-pack cellulose through small holes that are patched afterward.

An electrician must confirm it is inactive or replace it before we fill those walls.

Yes. Filled walls cut outside noise noticeably, and open-cell foam in open walls helps even more.

It makes rooms feel more even and comfortable. Many owners notice it most on cold mornings and hot afternoons.

New conditioned space must meet the California Energy Code. Your plans show the required insulation values.

No. It is one way to meet the values, especially in tight framing. Batts and blown-in work in many assemblies.

Yes. Tell us when rough-in is done and when inspection is booked.

Yes. Foam on walls and ceiling makes a garage or workshop more comfortable.

Only if it is soiled, wet, moldy or blocking air sealing. Clean, dry material can stay.

The vacuum hose runs outside, and we protect the access area.

Yes. Entry points should be closed before new insulation goes in.

We leave it alone and recommend testing.