Spray foam service
Closed-Cell Spray Foam in Fargo, ND
High R-value, moisture-resistant foam for walls, roofs, rim joists, and crawl spaces.
Closed-cell spray foam is the highest-performing insulation for Fargo's Climate Zone 7 — roughly R-6 to R-7 per inch, and it doubles as an air and vapor barrier, which is why it's the right call for rim joists, crawl spaces, and any assembly that faces North Dakota cold head-on.
Closed-cell spray foam is the workhorse for North Dakota's climate. It delivers one of the highest R-values per inch of any insulation, forms a rigid air and moisture barrier, and even adds structural strength to walls. It's our go-to for rim joists, crawl spaces, basement walls, and exterior walls that face the worst of the Fargo cold.
Because it resists moisture, closed-cell foam helps prevent the condensation and mold problems that plague poorly sealed crawl spaces and basements through our freeze-thaw cycles and humid summers.
We install closed-cell foam across the metro, from the older basements of Moorhead and Glyndon to newer builds in West Fargo.
- Highest R-value per inch — more performance in less space
- Acts as an air and moisture barrier in one application
- Adds rigidity and strength to the structure
- Ideal for crawl spaces, rim joists, and exterior walls
Good to know
Closed-Cell Spray Foam — Common Questions
How thick does closed-cell spray foam need to be in North Dakota?
For code and real-world performance in Climate Zone 7, closed-cell is typically applied at 2–3+ inches depending on the assembly. At about 2 inches it also qualifies as a Class II vapor retarder, so no separate poly sheet is needed over it.
Does closed-cell spray foam need a separate vapor barrier?
No. At roughly 2 inches, closed-cell foam is its own vapor retarder. Adding a poly sheet over it creates a second condensing surface and can trap moisture, so we never double up.
Is closed-cell worth the extra cost over open-cell in Fargo?
For rim joists, crawl spaces, basement walls, and exterior walls that take the full force of ND winters, yes. The higher R-value per inch and moisture resistance are exactly what our freeze-thaw climate demands.
Can closed-cell spray foam add structural strength?
Yes. Once cured it's rigid and bonds to the framing, adding racking strength to walls and roof decks — a real bonus in a high-wind region like the Red River Valley.
From our blog
More on Closed-Cell Spray Foam
Jul 20, 2026
Spray Foam, Moisture, and Vapor Barriers in North Dakota Homes
Does spray foam need a vapor barrier in North Dakota? Here's how closed-cell and open-cell foam handle moisture in Climate Zone 7, and how to avoid the mistakes that rot sheathing.
Read more
Jun 18, 2026
Why Fargo Basements Lose So Much Heat at the Rim Joist (and How to Fix It)
The rim joist is one of the biggest hidden sources of heat loss and cold drafts in Fargo-area basements. Here's why it leaks and how spray foam seals it for good.
Read more
Jun 11, 2026
Open-Cell vs. Closed-Cell Spray Foam: Which Is Right for a North Dakota Home?
A plain-English comparison of open-cell and closed-cell spray foam for Fargo-area homes — R-values, moisture, cost, and where each one belongs in a North Dakota climate.
Read more