Open-cell and closed-cell
Spray Foam Insulation in New Orleans, LA
One layer that insulates and air seals, matched to the attic, floor or wall it goes in.
- Free on-site estimates
- Itemized written quotes with material, depth and R-value
- Under-floor, attic and moisture problems checked first
Foam for How These Houses Are Built
Spray foam insulation is sprayed as a liquid, expands into cracks and cures into a solid layer that both insulates and stops air. In New Orleans houses, where humid air leaks through floorboards, around old windows and into hot attics, the air seal is often what owners notice first. We use two kinds of foam and pick between them for each surface.
Closed cell vs open cell
Open-cell foam is light and spongy, expands about a hundred times its liquid volume and runs about R-3.5 to R-3.7 per inch per HomeGuide. It is the usual choice under roof decks because it fills deep rafter bays at a reasonable price and leaves roof leaks visible from below. Closed-cell foam is dense and hard, about R-5 to R-7 per inch, slows water vapor and does not soak up water. In a city where floods and storm leaks are part of life, closed-cell belongs under raised floors, in the lower parts of walls being rebuilt, and on any surface that could get wet.
Under raised floors
A house on piers has its floor framing hanging in outside air. Fiberglass batts between the joists sag and fall over time, and wet ones hold water against the wood. Closed-cell foam sprayed to the underside of the subfloor and the sides of the joists seals the gaps between the boards, insulates, and keeps humid air off the framing. It holds its shape for good. We leave inspection gaps at the piers for termite checks.
Under the roof
If your air handler and ducts are in the attic, foam on the underside of the roof deck and the gable walls brings them inside the insulated space. The attic stays near house temperature instead of baking, and leaky ducts stop pulling in superheated air. See our Attic Encapsulation page for how that changes ventilation and humidity.
In walls
Gutted walls in a renovation are fast to foam. Louisiana's code summary lists R-13 for wood-frame walls in zone 2. Open-cell meets that in a 2x4 wall; closed-cell meets it in less depth and adds stiffness. Finished plaster walls are usually better filled with dense-pack cellulose; our Wall Insulation for Older Homes page explains that.
What foam does not fix
Foam does not stop a leak, and it hides rot and termite damage if it goes over them. We look for those first. It also should not cover old knob-and-tube wiring until an electrician has looked at it. After spraying, HomeGuide advises staying out for at least 24 hours while the foam cures. Get a free estimate
Where We Use Spray Foam
Common foam jobs in New Orleans houses.
Underside of raised floors
Closed-cell sealing drafts between floorboards and insulating the joist bays.
Roof decks
Open-cell or closed-cell under the sheathing to seal the attic around ducts and equipment.
Camelback and kneewalls
Sealing the walls and floors around upstairs rooms in camelbacks and half-stories.
Gutted walls
Foam in open studs during renovations and flood repairs.
Rooms over garages and porches
Floors that sit over open or unconditioned space.
Published Spray Foam Insulation Costs
| Job | Range and source |
|---|---|
| Spray foam, installed | $1.50 to $5.00 per sq ft (HomeGuide) |
| Open-cell / closed-cell | $1.50 to $3.50 / $3.00 to $5.00 per sq ft (HomeGuide) |
| About 1,000 sq ft | $1,500 to $5,000 (HomeGuide); $3,150 to $7,500 existing home (Fixr) |
| Existing walls / new construction | $3.15 to $7.50 / $2.75 to $6.50 per sq ft (Fixr) |
| All exterior walls | $4,000 to $10,000 (HomeGuide) |
| Whole house | $8,000 to $20,000 (HomeGuide); $10,000 to $30,000 (Fixr) |
| Typical job minimum | $1,000 to $2,000+ (HomeGuide) |
National numbers from HomeGuide (2026) and Fixr (2025). Thickness, access under the house or in the attic, and prep work move the total, and small jobs often hit a minimum. The number on our written estimate is the price.
How a Foam Job Goes
1. Look
Check for leaks, rot, wiring, termite signs and clearances under the house.
2. Quote
Foam type, thickness, R-value and price by area.
3. Prep
Protect floors and finishes, mask, set up ventilation.
4. Spray
Apply in passes to the planned thickness, trim where needed.
5. Hand back
Clean up and tell you when the house can be reoccupied.
Why Choose Us for Spray Foam Insulation
Right foam per surface
Closed-cell where water could reach, open-cell under roofs.
Termite gaps left
Inspection strips stay open at piers and edges.
Thickness on paper
Every area lists thickness and R-value.
Spray Foam Insulation Questions
Who manufactures spray foam insulation?
Several companies make spray foam systems for contractors. We tell you which product we plan to use on your quote, and you can look up its data sheet.
Is closed-cell worth the extra cost under a raised house?
Usually, because it does not soak up water and it holds up in outdoor air better than batts. Open-cell is not a good choice under a raised floor.
Will foam under the floor trap moisture in the wood?
Closed-cell slows vapor but the subfloor can still dry to the inside of the house. Problems come when a leak wets the wood, so plumbing leaks get fixed first.
How long does spray foam take to cure?
It firms up quickly, but HomeGuide advises staying out of the house for at least 24 hours. We confirm the timing for your job.
Spray Foam Insulation Service Areas
- Spray Foam Insulation in New Orleans, LA
- Spray Foam Insulation in Metairie, LA
- Spray Foam Insulation in Kenner, LA
- Spray Foam Insulation in Harahan, LA
- Spray Foam Insulation in River Ridge, LA
- Spray Foam Insulation in Jefferson, LA
- Spray Foam Insulation in Gretna, LA
- Spray Foam Insulation in Terrytown, LA
- Spray Foam Insulation in Harvey, LA
- Spray Foam Insulation in Marrero, LA
- Spray Foam Insulation in Westwego, LA
- Spray Foam Insulation in Belle Chasse, LA
- Spray Foam Insulation in Chalmette, LA
- Spray Foam Insulation in Arabi, LA
- Spray Foam Insulation in Slidell, LA
- Spray Foam Insulation in Destrehan, LA
Get a Spray Foam Insulation Estimate
Tell us which parts of the house you are thinking about and we will send a written foam plan.