Quick answer: Spray foam insulation in Greenville costs $1.00–$1.60 per board foot for open-cell and $1.60–$2.60 per board foot for closed-cell. Full scopes are quoted from measured board feet after an on-site evaluation of thickness, access, prep, and existing insulation. Most jobs finish in one day. Final pricing depends on access, required thickness, and any removal of existing insulation.
Spray Foam Insulation in Greenville, South Carolina
South Carolina Spray Foam Insulation, has been working in and around Greenville for more than 15 years. This is our home market, and it is where we see the full range of insulation problems: older homes near downtown Greenville with vented crawl spaces and settled wall insulation, and steady new construction pushing out along I-85 and the I-385 corridor. We work with homeowners updating an existing house and with builders framing new subdivisions across Greenville County.
Most Greenville homes we inspect are not short on insulation alone. They leak air. Upstate humidity rides in through crawl space vents, rim joist gaps, and attic penetrations, and the heating and cooling system pays for it every month. South Carolina sits in IECC Climate Zone 3A, which makes the attic the highest-priority assembly for insulation, but R-value without air control only does half the job. That is why our work goes past spraying foam. We also handle crawl space encapsulation, attic insulation, energy audits, duct blast testing, and blower door testing, so we can measure what a house is actually doing before and after we insulate it.
Why Greenville homes need spray foam
Greenville summers are long and humid, and a vented crawl space pulls that humid air straight under the house. When it reaches cooler ducts, joists, and subflooring, the moisture condenses. Homeowners usually notice the musty smell or a cupped hardwood floor before they ever look under the house. Left alone, that cycle runs every year.
Attics have the opposite problem. A Greenville attic in July is brutally hot, and many older homes still have blown or batt insulation that has been shifted around by wiring work, HVAC changes, or storage. A few inches of disturbed insulation does nothing about the air leaking around ceiling penetrations, light fixtures, and the attic hatch. Heat moves through materials, through moving air, and by radiation, and a house with gaps loses conditioned air by all three routes at once.
Spray foam deals with the air movement and the R-value in the same application. Closed-cell spray foam provides about R-6 to R-7 per inch. Open-cell spray foam provides about R-3.5 to R-4 per inch. Closed-cell is the usual choice for crawl spaces and rim joists because it resists moisture. Open-cell works well in attics and wall cavities where there is depth to fill. We pick the foam after we see the house, not before.
Our spray foam services in Greenville
Our scope in Greenville covers new construction, crawl space encapsulation, attic insulation, energy audits, duct blast testing, and blower door testing. The testing matters as much as the spraying, because it tells us where the leaks are and how much material a job actually needs. For builders, duct blast testing is required on new construction in South Carolina, and we run it as part of the new-build scope.
Crawl space spray foam
Many Greenville homes, especially older ones closer to downtown Greenville, sit on vented crawl spaces with exposed floor systems. We regularly find falling fiberglass batts, open foundation vents, and rim joists that leak at every bay. Closed-cell spray foam seals the crawl space perimeter and insulates the foundation edge in one pass. Where the moisture problem is bigger, full crawl space encapsulation with a vapor barrier is the right fix, and foam is one part of that system. Before we spray, we check access, duct location, and whether old insulation has to come out so the foam bonds to a clean surface.
Attic spray foam
If the ductwork and air handler sit in the attic, the cooling system loses performance before conditioned air ever reaches the rooms. Foaming the roof deck brings the attic inside the thermal boundary and takes that load off the equipment. Other homes are better served by air sealing the attic floor and insulating there instead. We decide based on roof condition, ventilation, HVAC layout, and what insulation is already in place. Open-cell foam is often the attic choice because the framing depth is there to use.
Rim joist and foundation walls
Rim joists are a small area, but they leak a surprising amount of air, and plenty of older Greenville homes have rim joists that were never insulated at all. Closed-cell foam fills the wood-to-foundation transition and delivers strong R-value in a narrow space. For existing finished walls, we can often add insulation without gutting the room. Using thermal imaging to find thin or empty cavities, we drill small holes just large enough for the spray nozzle and fill the wall from there. Patching a few small holes costs far less than removing all the drywall.
What does spray foam cost in Greenville?
Spray foam is quoted by board foot, not by a generic project total. Open-cell spray foam typically runs $1.00-$1.60/bf. Closed-cell spray foam typically runs $1.60-$2.60/bf. Where a job lands in that range depends on access, foam thickness, removal of existing insulation, surface prep, and whether the work is in an attic, crawl space, wall cavity, or rim joist line. In Greenville, crawl space access in older in-town homes is often the biggest variable. New construction prices differently than retrofit work because the surfaces are open and testing may be part of the same scope.
One note on incentives: the federal 25C energy efficiency credit expired Dec 31 2025, so no federal credit applies now. Duke Energy has offered rebates for qualifying efficiency upgrades in the past, and those programs change. Confirm current Duke Energy rebate details before your estimate rather than counting on an old figure.
