Open-cell
Lighter, fills more cavity
Useful for many interior attic and roofline applications when there is depth to work with. Expands more. Not a universal moisture barrier. Price is usually the lower of the two.
Ask which foam fits my projectSt. George, Washington, Ivins, Santa Clara, Hurricane
Open-Cell vs Closed-Cell Spray Foam in St. George, UT
Two products. Different density, moisture behavior, thickness, and price. The assembly decides, not a brand preference.
Reference
Reference photo — not a completed St. George job 
Reference photo — not a completed St. George job
Chooser
Start here, then read the table
Closed-cell
Denser, more R per inch
Used where space, rigidity, or moisture resistance matter. Costs and application constraints differ. Not a fire-rating, code, or health guarantee from this page.
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What actually differs
| Topic | Open-cell | Closed-cell |
|---|---|---|
| Density / expansion | Lighter. Expands more and fills irregular cavities. | Denser. Less expansion; higher R-value per inch. |
| Typical locations | Many interior attic and roofline applications when the assembly allows it. | Where space is tight, rigidity helps, or moisture resistance is the question. |
| Moisture behavior | Not a universal moisture barrier. Vapor drive still has to be evaluated. | More moisture-resistant, but not a blanket waterproofs-the-house claim. |
| Thickness / space | Needs more thickness to hit a given R-value. Fine when depth exists. | Useful when you cannot get depth: cathedral ceilings, thin walls, tight rims. |
| Relative price | Usually the lower installed cost of the two. Call for a quote. | Usually the higher installed cost. Application constraints differ. Call for a quote. |
| Questions to ask | Is the attic staying vented? Where are the ducts? What is already in the cavity? | Is space the limiter? Any moisture or below-grade contact? Ignition / thermal barrier plan? |
Final recommendation depends on assembly, climate exposure, code, ventilation, moisture, and access. This page does not make code, fire-rating, rebate, or health guarantees.