Two kinds of spray foam, two different jobs. Here's the honest, plain-English breakdown — no upsell — so you know which one fits your Waco building before we ever quote it.
Almost every spray foam question comes down to this one: open-cell or closed-cell? They're both spray-applied foams that insulate and air-seal, but they behave differently, cost differently, and suit different parts of a building. Here's the straight comparison.
| Open-Cell | Closed-Cell | |
|---|---|---|
| R-value per inch | ~R-3.6 | ~R-6 to R-7 |
| Density | Light, soft, spongy | Dense, rigid |
| Moisture | Vapor-permeable | Water-resistant; vapor retarder at ~2″+ |
| Cost per board foot | Lower | Higher |
| Sound damping | Excellent | Good |
| Adds rigidity | No | Yes |
| Best for | Attics, interior walls | Metal buildings, crawl spaces, tight cavities, moisture-prone areas |
Neither is “better” — they're tools for different jobs. The right answer depends on the assembly, the moisture exposure, how much space you have, and your budget. Anyone who says one foam is always the answer is selling, not advising.
Recognize a few of these? A free estimate tells you what sealing the envelope would do for your building.
Attic deck, wall cavity, metal roof, crawl space — the location largely drives the choice before anything else.
Moisture-prone or metal surfaces point to closed-cell's water resistance and vapor control; dry interior applications open the door to open-cell.
Where depth is limited and you need high R-value, closed-cell's ~R-6.5/inch wins; where there's room, open-cell can reach targets more affordably.
Maximum performance, moisture protection, sound, or best value per square foot — we recommend the foam that actually serves your priority.
You get the recommendation, the reasoning, and the price in your written estimate — so you can see exactly why we chose what we chose.
The reason this page exists: the Waco competitor with the older site has an open-vs-closed page too, but it won't tell you the honest version — that the answer is “it depends,” and depends on your building. Our whole approach is to recommend the foam that fits the job, not the one with the bigger ticket. In a humid climate like ours, that often means closed-cell on metal and moisture-prone areas, and open-cell where a cost-effective air seal is what the space needs. We'll show you the math for your project.
Tell us about your building. We'll measure, recommend the right foam and R-value, and put it in writing.
No. Closed-cell has nearly double the R-value per inch, which matters in tight spaces and on metal — but in an open attic where there's room to spray, open-cell can reach the same target more affordably. Higher R-per-inch isn't the same as better for every job.
Often open-cell, because attics usually have room to reach the R-value target and open-cell is a cost-effective air seal. But if you're encapsulating a roof deck with specific moisture considerations, closed-cell may fit. We recommend per home.
Open-cell is vapor-permeable, so in the right assembly it lets moisture dry out — but it needs to be designed correctly for the location. That's why assembly and moisture strategy drive the recommendation, and why we don't apply it blindly.
Yes — it's common to use closed-cell where moisture and rigidity matter and open-cell where a cost-effective air seal is enough. We'll spec each area to what it needs.
R-value, climate-zone, and local weather figures cited above are drawn from public, authoritative sources so you can verify them independently.
Free estimate, honest foam recommendation, no pressure.
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