Spray Foam Insulation FAQ

Open-cell foam (0.5 lb/ft³) expands dramatically, fills large volumes cost-effectively, and is vapor-permeable. It provides R-3.7 per inch and excellent sound dampening. Closed-cell foam (2 lb/ft³) is denser, provides R-6.5 per inch, acts as a vapor retarder, and adds structural rigidity. In San Antonio's climate, closed-cell is recommended for exterior walls, crawl spaces, and any moisture-exposed assembly. Open-cell is appropriate for attic roof decks and interior partitions.

For most San Antonio attics, open-cell spray foam applied to the underside of the roof deck is the best value — it seals air completely and keeps conditioned air inside the thermal envelope. Closed-cell foam is recommended where moisture resistance is needed, such as in crawl spaces or under roof decks with potential leak exposure. Our free estimate includes a site-specific recommendation.

Yes, for most applications. Fiberglass meets the nominal R-value but does not air seal — and air leakage accounts for 25–40% of typical energy loss. Spray foam insulates and air seals in one step. With San Antonio's long cooling season and 100°F+ summer temperatures, most homeowners recoup the spray foam premium through energy savings in 3–6 years, while enjoying meaningfully better comfort from day one.

San Antonio falls in IECC Climate Zone 2B (hot-dry to hot-mixed). This zone requires R-38 minimum in attics, R-13 in exterior walls, and R-19 in floors over unconditioned spaces. Spray foam often exceeds these minimums while providing the air sealing and vapor control that fiberglass at minimum R-value cannot achieve.

San Antonio and Bexar County follow the International Building Code (IBC) and International Residential Code (IRC). Exposed spray foam in living spaces requires a 15-minute thermal barrier (typically drywall). Some applications using listed assemblies or intumescent coatings may be exempt. We handle all code-relevant specifications for every project.

San Antonio sits at the edge of Hill Country, where humidity can swing significantly — especially during the spring and fall wet seasons. Without a proper air seal, warm moist air reaches cold surfaces inside your ceiling assembly, leading to condensation, mold risk, and degraded insulation performance. Closed-cell foam in exterior assemblies provides the vapor retarder that prevents this moisture infiltration.

Yes. Closed-cell spray foam adds a moisture barrier in crawl spaces, rim joists, and exterior walls — reducing the humidity infiltration that is common throughout Bexar County and the surrounding Hill Country area. This is especially important in older neighborhoods like Alamo Heights and King William where the original building envelopes were not designed for modern moisture management.

Prices vary by foam type, thickness, and project size. Open-cell foam typically runs $0.44–$0.65 per board foot installed. Closed-cell runs $1.00–$1.50 per board foot installed. For a typical San Antonio home attic (1,800 sq ft), open-cell roof deck foam might run $2,800–$5,500. We provide free on-site estimates with written pricing for every project.

Results vary by home size and current insulation condition, but San Antonio homeowners typically see a 20–40% reduction in cooling costs after a full attic spray foam install. Homes with old or poorly installed fiberglass see the biggest gains. Your free estimate will include a realistic savings breakdown based on your home's specific conditions.

Anytime — we work year-round. Summer months (June–September) book up faster as homeowners react to high electric bills, so scheduling 2–4 weeks in advance is recommended during peak season. Winter and early spring often have faster availability. For new construction, call as soon as framing is complete to lock in a pre-drywall slot.

Absolutely. We work regularly in neighborhoods like Alamo Heights, Mahncke Park, and King William where homes were built with little to no insulation. We assess access points, identify any existing moisture or air seal issues, and choose open-cell or closed-cell foam accordingly. Older homes often see the largest percentage improvement after foam installation.

During the spray, occupants should not be in the area being sprayed. Depending on the scope, you may be able to stay in another part of the house or may need to leave for the day. Foam typically reaches a safe state for re-occupancy 24 hours after application. We walk through the specifics during the estimate.

Properly installed spray foam is a permanent installation. It doesn't settle, sag, or lose R-value over time. Unlike fiberglass batts that can shift, develop voids, and absorb moisture over the years, spray foam is structurally stable. The manufacturer's technical data sheets confirm there is no measured degradation in R-value over the service life of the building.

Yes. We serve all of Bexar County and the surrounding region including Boerne, New Braunfels, Schertz, Cibolo, Bulverde, Fair Oaks Ranch, and communities along the 1604 and 281 corridors. Call us with your address for scheduling availability.