Barndominium Spray Foam Insulation

A barndominium is a house inside a metal building, and that is exactly why insulation decides how it lives. The steel skin heats up fast, cools down fast and sweats when humid air reaches it. Closed cell spray foam sprayed directly on the panels deals with all three, and it is the insulation most barndo builders and owners around North Texas end up choosing.

Why closed cell is the standard for barndos

• No condensation. Humid air can’t reach the cold steel, so the panels don’t sweat and drip into your walls.
• High R-value in thin walls. About R-6.5 per inch means 2″ on the walls and 3″ on the roof gets you to about R-13 and R-20 without deep framing.
• Air sealed. Panel laps, screw holes, the ridge and the base trim are sealed in one pass.
• Stronger and quieter. Foam bonded to steel and framing stiffens the shell and takes the drum out of rain and hail.

What thickness to ask for

Most of our barndo quotes are 2″ of closed cell on the walls and 3″ on the roof. If the living area will have a flat ceiling with its own insulation above it, some owners go thinner on the roof. If part of the building is a shop that won’t be air conditioned, it can get less foam than the house side. We quote each area separately so you can see the trade-off.

Interior walls between rooms don’t need closed cell. If you want them quieter, open cell or batts work fine there.

Spray area by size

The spray area is the walls plus the roof plus the gable ends, measured before doors and windows come out. Here is what common barndo sizes come to with a 4/12 roof, and what closed cell at 2″ on the walls and 3″ on the roof costs at our current prices.

Spray area = walls + roof at a 4/12 pitch + gable ends, before doors and windows are taken out.

Your building is probably not one of these sizes exactly. Plug in your width, length, wall height and roof pitch in the calculator for a range in a minute.

When to schedule spray foam in your build

Foam goes on after the shell is dried in and before the interior walls close it off. The usual order:

1. Steel building erected, roof and wall panels on.
2. Windows and exterior doors installed (or openings framed and covered).
3. Rough plumbing and electrical on the exterior walls, if any run on them.
4. Spray foam. We cover the slab, windows and doors and spray the roof and walls.
5. Interior framing, drywall and finish.

If your framing goes up against the steel before we spray, tell us. Foam can still go in, but the framing changes how we spray and sometimes the thickness we can get.

Ignition and thermal barriers

In the living space, foam gets covered by drywall like any other insulation, and that drywall is the thermal barrier the code calls for. In a shop or storage side that stays open, the foam may need an ignition barrier coating. Your quote lists which areas need what.

Barndominium questions

Is spray foam really necessary in a barndominium?

It is the most reliable way to stop the steel from sweating, and that is the problem that ruins drywall and framing in barndos. Batts and blankets can work with a perfect vapor retarder, but every tear and lap is a place for condensation. That is why closed cell foam on the panels has become the default for barndos in Texas.

Should I use open cell or closed cell in my barndo?

Closed cell anywhere the foam touches steel. Open cell lets moisture move through it and can trap condensation against the panels. Open cell is fine in interior walls for sound, or under a wood roof deck if your barndo has one.

Can you spray the shop side and the living side differently?

Yes, and many owners do. The house side gets the full 2″ walls and 3″ roof, and the shop side gets 1.5″ to 2″ everywhere to stop the sweating and take the edge off the heat. We price each area separately on the quote.

How long does a barndo take to spray?

Most 40×60 to 50×80 barndos take two to three days, depending on wall height and how much is open. Nobody should be inside while we spray or for about 24 hours after. Your other trades can usually be back the next day.

Do you work with my builder?

Yes. Send us the plans or the building package specs and we’ll quote from them, then confirm on site once the shell is up. We coordinate the date with your builder so foam happens right after dry-in.