Closed-cell spray foam in Roswell
This is the rigid foam. It costs more per inch, and around here it is rarely the attic product. It shows up under floors, at the band joist, on shops, and anywhere a wall is too skinny for open-cell to hit the R-value.
Denser on purpose
Same kind of spray gun, different mix. It expands maybe thirty to fifty times, not a hundred. The cured plastic is stiff, about 2 lb per cubic foot, and people cite R-6 to R-7 per inch. Thick enough, it slows vapor. Water that is already in a wall still has to dry out somewhere. In Roswell that is often to the outdoor air, if the assembly is built that way.
Crews spray thinner lifts because the stuff runs hotter while it cures. They usually stop at the inch count instead of trimming. Some manufacturers talk about racking strength. Treat that as a brochure line until someone shows you the evaluation. Don't skip a cracked stem wall because of it.
Where it actually gets used
Put a vapor retarder on the wrong side of a wet assembly and you can trap moisture. Smaller risk here than on the Gulf Coast. Still a problem if the roof already leaks, or if stucco cracks take a monsoon burst on a west wall.
- Crawls with bare soil and cold floors in January
- Rim joists on older ranches
- Metal shops, barns, equipment buildings
- Thin cavities that cannot hold enough open-cell
Steel buildings in this valley swing from a 100°F day to a freeze with almost no mass in the panels. Closed-cell on the underside is a common shop request. That quote has nothing to do with a 1,200-square-foot house attic. Say which building you have.
Foam against flues, can lights, and knob-and-tube is a spec problem, not a product virtue. If they never ask what is in the space, they are guessing.
Ask for board feet, product, and finished thickness. For crawls, ask whether a ground vapor barrier is in the number. Foam on the walls and bare dirt in the middle is a half plan.
If the attic is the thing that actually bothers you, start with open-cell and the attic page. Numbers live on the cost page.
Dry climate, so I can skip closed-cell?
Outdoor air is dry. Dirt under a house is not. Closed-cell is still the usual call against ground moisture, at rim joists, on metal buildings, and in walls that are too thin for enough open-cell.
Does closed-cell replace flashing and a ground cover?
No. It can act as a vapor retarder. It does not fix a roof leak, bad grade, or bare soil in a crawl. Ask what water problem they think they are solving besides insulation.
Why is every closed-cell bid higher?
More chemical per inch, higher R-value, and a rigid cure. Compare board feet and thickness. A cheap 1-inch pass is not the same job as 2 inches.
Get closed-cell quotes for crawls and shops
Tell us about the attic, crawl space, or building. Licensed local installers follow up. We do not send a crew.