Fast, Reliable Spray Foam Insulation Across San Antonio
Spray foam insulation in San Antonio runs $1.80-$3.20 per board foot for open-cell and $3.50-$5.50 for closed-cell, with most whole-attic jobs landing between $3,200 and $7,800 depending on accessibility and whether air sealing is needed first. Our crews dispatch from the San Antonio office and typically reach Stone Oak, Bulverde, and the Northside corridors within 45 minutes of a scheduled arrival window. We’ve worked the full sweep of San Antonio’s housing stock, from 1920s Westside pier-and-beam homes with zero wall insulation to 2016 master-planned builds where the garage ceiling was left bare and the rim joists were never touched.
San Antonio sits in IECC Climate Zone 2, one of the hottest designations in the continental U.S. Attic cavities here routinely hit 150°F+ from June through September, and the February 2021 Winter Storm Uri exposed how little thermal protection most local homes actually have for cold retention. That two-directional stress, heat and occasional hard freeze, is why we treat air sealing as a hard prerequisite before any foam goes in. Call (830) 402-5240 for a written price before any work starts.
Why Topside Attic Insulation Schertz Is San Antonio’s Preferred Spray Foam Insulation Company
We’ve sealed and insulated more than 9,000 homes since 2016, and the San Antonio jobs are some of the most instructive. The city’s combination of slab-on-grade construction, low-pitched roofs with intense solar gain, and high summer humidity creates failure modes you don’t see in drier West Texas markets. Our crews know the difference between a Northside 1989 tract home with settled R-22 fiberglass and a 2016 Stone Oak build with an uninsulated garage ceiling and Wi-Fi opener thermal faults. That local pattern recognition matters.
Reviews from San Antonio customers consistently mention two things: the before-and-after blower-door numbers we publish on every applicable job, and the fact that a live person answers the phone 24/7. No voicemail loops, no callback windows measured in business days. Our 365-Day Done Right Promise applies to all completed work, and every job closes with a Documented Photo Record so you can verify what was done without crawling through your own attic.
Response time to San Antonio neighborhoods is built into our scheduling. Dispatch and coordination run from our San Antonio office, and crews carry stock for same-day starts on most standard applications. We don’t ask you to call for pricing. Under Haven Standard Clause 1, you get a flat written price, a written scope, and a written warranty before anyone lifts a tool.
Our Spray Foam Insulation Services in San Antonio
Closed-Cell Spray Foam
Closed-cell spray foam in San Antonio runs $3.50-$5.50 per board foot and delivers R-6.5 to R-7 per inch with a built-in vapor retarder. On low-pitched roof decks in the Stone Oak-Bulverde corridor, where attic ventilation is often marginal and summer humidity peaks above 70 percent, closed-cell is frequently the correct call over open-cell. The material doesn’t absorb moisture, and at 2 inches it provides a Class II vapor retarder that helps prevent condensation on the underside of roof decking during shoulder-season temperature swings. We source closed-cell from Demilec and Johns Manville, with no proprietary lock-in that limits your options.
Open-Cell Spray Foam
Open-cell spray foam in San Antonio costs $1.80-$3.20 per board foot and delivers R-3.6 to R-3.8 per inch. It’s permeable to vapor, which can be useful in certain wall assemblies but requires careful placement in this climate. We rarely recommend open-cell on the underside of an unvented San Antonio roof deck unless the attic is being fully conditioned as part of the building envelope. The humidity-driven vapor load here is genuinely different from drier markets, and trapped moisture against roof sheathing is a repair we’ve been called to fix after other contractors made that call wrong.
Rim Joist Spray Foam
San Antonio’s housing stock is almost entirely slab-on-grade. That means the rim joist, the perimeter framing where the walls meet the foundation, is often the single largest uninsulated surface in the entire building envelope. Builder-grade construction here routinely skips this detail, leaving the sill plate as a continuous thermal bridge that undermines an otherwise correctly foamed attic. Rim joist spray foam in San Antonio typically runs $1,400-$2,800 for a standard single-family home, and the payback shows up immediately in rooms over garages and at exterior walls where the floor has always felt cold in winter or hot in summer. This is not an upsell. In Climate Zone 2, it’s code-critical.
Garage Ceiling Spray Foam
Our crew foamed the garage ceiling and rim joists of a 2016 two-story in the Stone Oak-Bulverde corridor after the homeowner’s Wi-Fi garage opener kept tripping its thermal safety in August. The builder-grade ceiling had zero insulation and the attic above it was clearing 150°F by noon. We shot 2 inches of closed-cell against the roof deck and sealed the rim joists in the same pass, and the opener’s internal temp dropped enough that it stopped faulting mid-cycle. The homeowner later told us the upstairs bonus room over that garage finally held temperature through the afternoon, which it never had under the original builder setup. Garage ceiling spray foam in San Antonio runs $1,800-$3,600 for a typical two-car bay, and we bundle it with rim joist work when the thermal imaging shows the connection point is leaking.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in San Antonio
We source spray foam materials from Demilec, Johns Manville, Owens Corning, and other manufacturers with distribution through San Antonio supply houses. That local stocking means we don’t wait on freight from Dallas or Houston when a job calls for a specific product density or vapor-retarder rating. For homeowners who want to compare spec sheets, we carry product data for every material we propose, and we don’t claim exclusive or preferred status with any brand. The right foam for your San Antonio home is the one that matches the assembly, the budget, and the written scope, not the one with the most marketing behind it.
Common Spray Foam Insulation Problems We See in San Antonio Homes
- Attic bypasses around recessed can lights in 1980s-90s Northside tract homes. These penetrations leak as much conditioned air into the attic as the entire settled insulation blanket was designed to stop. Foam sprayed without air-sealing those penetrations first fails to deliver the rated R-value in practice. We seal them with rigid covers and fire-rated caulk before any foam goes in.
- Moisture trapping under low-pitched roof decks with open-cell foam. San Antonio’s high summer humidity and marginal attic ventilation in many builder-grade homes means open-cell foam on a roof deck can accumulate moisture over multiple cooling seasons. The repair involves removal, drying, and reinstallation with closed-cell or a conditioned attic approach. It’s a mistake less punishing in drier markets.
- Uninsulated rim joists on slab-on-grade construction. Because San Antonio built outward rather than upward for decades, most homes have no crawl space and no basement. The rim joist becomes the thermal weak point by default, and builders routinely skipped it. We find this on energy audits across the Northside, Universal City corridor, and Southside alike.
- Garage ceilings left completely uninsulated in homes built 2010-2020. The master-planned growth belt from Stone Oak to Cibolo is full of homes where the garage was treated as unconditioned space even when a bonus room sits directly above it. The result is a room that can’t hold temperature and, increasingly, smart garage door openers that fault in summer heat.
Pricing for Spray Foam Insulation in San Antonio, TX
Here’s what spray foam insulation costs in the San Antonio market, based on jobs we’ve priced and completed under Haven Standard Clause 1:
| Application | Typical Range |
|---|---|
| Open-cell spray foam (per board foot) | $1.80 - $3.20 |
| Closed-cell spray foam (per board foot) | $3.50 - $5.50 |
| Whole attic, open-cell (typical 1,800 sq ft home) | $3,200 - $5,400 |
| Whole attic, closed-cell (same size) | $5,800 - $7,800 |
| Rim joist spray foam (standard single-family) | $1,400 - $2,800 |
| Garage ceiling spray foam (two-car bay) | $1,800 - $3,600 |
| Air sealing (prerequisite, priced separately) | $800 - $1,600 |
What moves the number: attic accessibility (steep roof pitch or limited hatch size), existing insulation removal, the condition of roof decking, and whether we’re working around active HVAC equipment. Every job gets a written price before any work starts, and we offer a Free Second Opinion on any written estimate from another contractor. Call (830) 402-5240 to schedule an assessment with documented photo record included.
We Also Serve Cities Near San Antonio
Our Spray Foam Insulation in San Antonio crews also work in Converse, Universal City, Schertz, and Cibolo, with the same written-price-first protocol and same-day scheduling available throughout the corridor. If you’re in one of these communities and your home matches the patterns we described, the pricing and approach are identical to what we apply in San Antonio proper.
Serving San Antonio, TX - Our Local Coverage Area
We’re based in the San Antonio area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs - Spray Foam Insulation in San Antonio
Because the builder left it uninsulated. In San Antonio’s Climate Zone 2, a garage attic clears 150°F by noon in summer, and that heat radiates straight through drywall into any room above. Smart garage door openers with thermal safety cutoffs fault out. We see this in 2016-2022 builds from Stone Oak to Cibolo regularly. Call (830) 402-5240 for a written price on garage ceiling and rim joist foam together.
Closed-cell is usually the correct choice for unvented roof decks in San Antonio. The humidity-driven vapor load here is higher than in drier West Texas markets, and open-cell foam can trap moisture against roof sheathing if attic ventilation is marginal. Closed-cell at 2 inches provides a vapor retarder and R-13+ in a single pass. We confirm the recommendation with thermal imaging and a blower-door test before quoting.
It fixes two decades of settled fiberglass and unsealed attic bypasses. Original blown fiberglass in Northside homes from this era has typically compressed from R-22 to an effective R-9 or R-10, and recessed can lights leak conditioned air at rates that match the insulation deficit. Our Spray Foam Insulation process starts with air sealing those penetrations, then foams to the correct R-value for Zone 2. The blower-door test before and after shows the combined result in one number.
It’s a real fix for a real thermal problem. The opener is protecting itself from ambient temperatures that exceed its design range because the garage ceiling was never insulated. We documented this exact case in a 2016 Stone Oak build: 2 inches of closed-cell on the garage ceiling and sealed rim joists dropped the opener’s internal temperature enough to stop the faults, and the bonus room above finally held temperature. The fix addresses the cause, not the symptom. Call (830) 402-5240 and we’ll thermal-image your ceiling to confirm.
Because there’s no crawl space or basement to provide a thermal buffer. The rim joist is where your exterior walls meet the foundation, and in slab-on-grade construction it’s often completely uninsulated. That makes it a continuous thermal bridge that undermines everything else in the envelope. In San Antonio’s housing stock, which is almost entirely slab-on-grade, this detail is skipped more often than not. Rim joist foam typically costs $1,400-$2,800 and is code-critical in Climate Zone 2. Call (830) 402-5240 for an assessment.
Get a Written Price Before Any Work Starts
Every spray foam insulation job in San Antonio begins with a written price, a written scope, and a written warranty under Haven Standard Clause 1. No exceptions. You’ll also receive a Documented Photo Record when the crew leaves, and on applicable jobs, before-and-after blower-door numbers so you can verify the air-sealing result in a single figure. Call (830) 402-5240 to schedule. A live person answers 24/7.
Written by Wes Okafor, Owner at Envelope Insulation Co., serving San Antonio since 2016.
Spray Foam Insulation in Nearby Areas
