What makes closed-cell different
Closed-cell spray foam is dense. It delivers higher R-value per inch than open-cell foam, adds air sealing, and can add vapor resistance in the right thickness. That combination is why it is often recommended for high-desert trouble spots.
It also costs more. The goal is not to use the most expensive foam everywhere; the goal is to use it where the building actually benefits.
Best-fit areas in Cedar City homes
- Rim joists: high air leakage, tight space, strong return on sealing.
- Crawl-space walls: useful when moisture is controlled and access is limited.
- Rooflines: helpful in certain unvented attic assemblies or complex roof planes.
- Shops and garages: durable air sealing for big temperature swings.
Where open-cell may be better
Open-cell foam can make sense for interior sound control and large cavities where vapor resistance is not desired. It expands more and costs less per volume. In some assemblies, that is exactly what you want.
That is why a good installer talks about assemblies, not just products. Foam choice depends on the surface, moisture risk, required R-value, and code requirements.
Do not skip the code conversation
Spray foam often requires ignition or thermal barriers depending on location and access. Ask whether those requirements are included in the quote. This is especially important in attics, crawl spaces, and storage areas.
Common questions
Is closed-cell foam waterproof?
No. It resists moisture better than open-cell foam, but it is not a substitute for fixing leaks, drainage, or bulk water.
How thick should closed-cell foam be?
Thickness depends on the assembly and code target. A quote should state the planned thickness and why it is enough.
Is closed-cell always better?
No. It is stronger and denser, but open-cell may be better for some interior cavities and budgets.