Two foams, two different jobs — and in the wettest part of Texas, the moisture column of this comparison matters more than anywhere else in the state. Here's the honest breakdown.
Every spray foam conversation eventually arrives at this question: open-cell or closed-cell? Both insulate and air-seal, but they behave differently, cost differently, and suit different parts of a building — and in East Texas, the moisture properties tilt the answer more often than they would in Waco or Abilene. 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″+; FEMA-classified flood-resistant |
| Cost per board foot | Lower | Higher |
| Sound damping | Excellent | Good |
| Adds rigidity | No | Yes |
| Best for (East Texas) | Attics, interior walls | Crawl spaces, metal buildings, rim joists, moisture-prone areas |
Neither foam is “better” — they're tools for different jobs. But be wary of anyone in East Texas who specs open-cell against metal or in a crawl space. In the wettest corner of the state, the moisture column isn't a footnote; it's often the deciding row.
Recognize a few of these? A free estimate tells you exactly what sealing your building would do.
Attic, wall cavity, crawl space, metal skin — the location largely decides before anything else does.
In East Texas this is the big filter: crawl spaces, metal, and rim joists point hard to closed-cell; dry interior assemblies open the door to open-cell.
Limited space plus a high R-target favors closed-cell's ~R-6.5/inch; open attics with room can hit targets more affordably with open-cell.
Maximum performance, moisture protection, sound, or best value per square foot — the recommendation serves your actual priority.
Your estimate shows the foam, the thickness, and the reasoning per area — so you can see exactly why we specced what we specced.
Here's the East Texas-specific version of the honest answer. In dry parts of the state, open-vs-closed is mostly an R-value-and-budget conversation. Here, with about 45.8 inches of normal annual rainfall and humidity most of the year, it's a moisture conversation first: closed-cell's water resistance and vapor control make it the default for crawl spaces, metal, and rim joists, while open-cell remains the value play for attics and interior walls where the assembly stays dry. We spec both, often on the same house — each where its properties actually fit.
Tell us about your building. We'll measure, recommend the right foam and R-value, and put it in writing.
No. It has roughly double the R-per-inch, which wins in tight cavities and on metal — but in an open attic with room to spray, open-cell reaches the same target more affordably. Higher R-per-inch isn't the same as better for every job.
Often open-cell — attics usually have room to hit the R-value target and open-cell is the cost-effective air seal. Roof-deck encapsulations with specific moisture considerations may call for closed-cell. We recommend per home.
Closed-cell, and in our climate we'd push back on anything else. Both environments are moisture-exposed here, and closed-cell is the water-resistant, vapor-retarding option built for them.
Yes — it's common and often optimal: closed-cell in the crawl space and on rim joists, open-cell in the attic and walls. Each area gets what its conditions demand.
R-value, climate-zone, rainfall, and building-science figures cited above come from public, authoritative sources so you can verify them independently.
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