Spray Foam for New Construction

A house under construction is the easiest and least expensive time to spray foam. The walls are open, the roof deck is bare, and nobody is living there. Spraying the exterior walls and the underside of the roof deck gives you a tight house from day one, with the attic, the ducts and the air handler inside the conditioned space.

What we spray in a new house

• Exterior walls: open cell fills 2×4 walls at 3.5″ (about R-13) and 2×6 walls at 5.5″ (about R-20), and seals around every outlet box, pipe and wire.
• Roof deck and gable walls: open cell at 5.5″ to 7″ (about R-20 to R-25) seals the attic so the HVAC equipment lives in mild air.
• Rim joists and floor transitions: closed cell on the band joists of a two-story and on floors over garages or porches.
• Problem spots: closed cell where framing is shallow, like vaulted ceilings, so you still get the R-value you need.

Interior walls can get open cell or batts for sound if you want quieter bedrooms, offices or media rooms.

When to schedule us

Foam goes in after the framing, windows, exterior doors and rough-ins (plumbing, electrical, HVAC, low voltage) and after any inspection that needs to see them. It goes in before drywall. In practice:

1. Framing done, house dried in with windows and doors.
2. Rough-ins complete and inspected.
3. Spray foam. We cover windows and openings and spray walls and roof deck.
4. Insulation inspection or energy rater visit, if your build has one.
5. Drywall.

Trades can usually be back in the house the day after we spray. Tell us your target drywall date and we’ll work back from it.

Tell your HVAC contractor early

A foamed house with a sealed attic needs less cooling than the same house with a vented attic. If the system is sized for a leaky house, it will short-cycle and leave humidity behind. Ask your HVAC contractor to size the equipment for a sealed attic (a Manual J load calculation does this), and plan for fresh air, since a tight house needs a deliberate source of ventilation. Your energy rater can test the result with a blower door.

For builders

We quote from plans, then confirm on site once the house is framed. If you build several homes a year, we can set up standard specs and pricing per plan so every house is quoted the same way.

New construction questions

Is spray foam worth it over batts in a new house?

Batts cost less for walls, but they don’t seal air, and gaps around wiring and plumbing add up. The bigger difference is the attic: foam on the roof deck puts your ducts and air handler inside the house instead of in a 130°F attic. For most Texas homes, the roof deck is where foam pays off first.

Will spray foam help us pass the blower door test?

Foam seals the walls and roof deck, which is where most leakage in a new house happens. The rest depends on everything else that penetrates the shell: windows, doors, the slab edge, recessed lights and duct boots. We seal what we spray carefully and point out gaps we see on site.

Can you spray before the rough-ins are done?

We can, but we don’t recommend it. Electricians and plumbers end up cutting through fresh foam, which leaves holes and gaps. Spraying after rough-ins means everything is sealed in one pass.

Open cell or closed cell in the walls?

Open cell for most 2×4 and 2×6 walls in a house. Closed cell when you need more R-value in thin walls, extra stiffness, or a vapor retarder. Some builders use closed cell in a garage that will be air conditioned or in walls next to a pool or outdoor kitchen.