Trusted Spray Foam Insulation for San Antonio Homeowners
If you’re wondering how much Spray Foam Insulation costs, San Antonio prices typically run $1.50 to $4.50 per board foot installed, with most whole-home projects between $4,000 and $12,000 depending on square footage and whether you choose open-cell or closed-cell foam. We can usually schedule your estimate within 48 hours and complete the job the same week. If your AC is running constantly from June through September and your energy bills still climb past $250, spray foam is likely the fix.
Walt’s Insulation has been insulating homes across Bexar County since 2000. Walt Brenner still runs the company himself, and his name is on every job we do. When you call (866) 751-4428, a real person answers, any hour of the day or night. Not a voicemail tree. Not a call center in another state. That matters when your attic is 140 degrees and you want answers, not a recording.
Key Takeaways
- Spray foam installation in San Antonio runs $4,000 to $12,000 for a typical whole-home project.
- Open-cell foam works best for interior walls and attic ceilings; closed-cell handles moisture, high heat, and structural reinforcement.
- We’re locally owned, owner-operated, and every job carries our lifetime Done Right Promise.
- Live people answer our phones 24/7. Free second opinions on any written estimate, no trip charge in our service county.
What Our Spray Foam Insulation Service Includes
We handle every type of spray foam application a San Antonio home could need, from open-cell attic work to closed-cell moisture barriers. Each job starts with a full assessment of your home’s air envelope so we can recommend the right foam for the right space. Here’s what we do.
Open-Cell Spray Foam
Open-cell foam is the lighter, more flexible option, and it’s what we install most often in San Antonio attics and interior walls. It expands to roughly 100 times its liquid volume, filling stud cavities and rafter bays completely so air can’t sneak through the gaps fiberglass batts always leave behind. Because it’s vapor-permeable, open-cell lets moisture move through it rather than trapping it against framing, which matters in our humid Gulf-adjacent climate. We install open-cell products from Icynene and Demilec, two manufacturers we’ve worked with for over a decade.
Closed-Cell Spray Foam
Closed-cell foam costs more per board foot but earns its keep in specific San Antonio situations: exterior walls, rim joists, and any space exposed to moisture or standing water. It cures rigid, denser than open-cell, with an R-value around R-6.5 to R-7 per inch, roughly double what open-cell provides. That density also adds structural strength to wall assemblies, which older San Antonio homes can genuinely benefit from. Our crews are trained on Demilec and CertainTeed closed-cell systems, and we warranty the workmanship for life.
Rim Joist Spray Foam
The rim joist, where your floor framing meets the foundation wall, is one of the leakiest parts of a San Antonio house. It’s also a prime entry point for rodents, roaches, and outside air. We seal rim joists with closed-cell foam to stop air infiltration and create a barrier pests won’t chew through. In crawl space homes common to older neighborhoods like Monte Vista and Alta Vista, this one fix can drop winter floor drafts by a noticeable margin - similar to the results we see with Spray Foam Insulation in Pasadena.
Garage Ceiling Spray Foam
If your garage sits under a bedroom or bathroom, you know exactly how hot that room gets every summer afternoon. A garage ceiling sprayed with open-cell foam creates a thermal break between the sun-baked garage and the living space above it. We’ve done this for homeowners all over Stone Oak and Alamo Heights who couldn’t get their upstairs rooms below 80 degrees, and for those seeking Spray Foam Insulation - Humble residents can expect the same relief. The difference is immediate and measurable.
Spray Foam Roof Deck
For unvented attic designs, we spray foam directly against the underside of the roof deck, sealing the entire attic space. This keeps your ductwork inside the conditioned envelope instead of roasting in a 140-degree attic, which is standard San Antonio construction. It’s the most effective way to cut cooling costs in homes where ducts run through the attic, and it also helps reduce dust and pollen pulled into the house. We recommend closed-cell for roof decks in most San Antonio homes because the added structural rigidity holds up better under high winds.
What happens when you call
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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.
Brands We Service for Spray Foam Insulation
We install Icynene open-cell and closed-cell systems, and we’ve been certified with them long enough to know exactly how their foam behaves in San Antonio’s heat and humidity. Icynene’s open-cell formula expands aggressively, which helps us reach into tight rafter bays and odd-shaped cavities that other foam products leave behind.
We also work with Demilec and CertainTeed closed-cell products for applications where moisture resistance and structural integrity matter most: rim joists, basement walls, and crawl space encapsulation. Whether you have a preference for one of these brands or just want our honest recommendation based on your home’s specific conditions, we’ll walk you through it before any foam is sprayed. If another contractor quoted you a different brand, bring us that quote and we’ll give you a free second opinion on it.
Signs You Need Spray Foam Insulation Right Now
- Your upstairs rooms won’t cool below 80 degrees in July. This is the number one complaint we hear from San Antonio homeowners in two-story houses. The attic is superheating the upstairs ceiling, and no amount of AC maintenance fixes insulation that isn’t doing its job. Spray foam on the roof deck or attic floor addresses the root problem instead of fighting the symptom.
- Energy bills creep higher every year while your usage habits stay the same. Fiberglass batts settle, shift, and lose effectiveness over time. If your CPS Energy bill has climbed 20% or more in the last three years without a corresponding change in thermostat settings, your insulation envelope is degrading. Spray foam doesn’t settle, ever.
- You can feel drafts around baseboards or exterior walls in winter. San Antonio winters are mild, but a drafty house still costs you money in January and February. Air is entering through rim joists, wall cavities, and around window framing. Closed-cell spray foam seals those paths permanently, which fiberglass and cellulose simply can’t do.
- You’re finding mouse droppings or roach activity in the kitchen or pantry. Pests follow air leaks. Where air moves, insects and rodents move. Sealing the rim joist and wall cavities with closed-cell foam closes the highway they’re using to get into your living space. We’ve seen this fix dramatically reduce pest issues in San Antonio homes near the Salado Creek Greenway and other wooded areas.
- Your attic smells musty or you’re seeing mold on ceiling drywall. San Antonio’s humidity finds its way into attic spaces and condenses on cool surfaces. Spray foam, particularly closed-cell, creates an air and moisture barrier that keeps humid outside air out of your attic assembly entirely. Mold needs moisture to grow; cut the moisture, you cut the problem.
Our Spray Foam Insulation Process - Step by Step
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Free on-site assessment. We walk your home, inspect the attic, crawl space, walls, and rim joists, and take thermal readings with an infrared camera. You get a written quote with exact square footage and board-foot pricing before we do anything else. No vague “around $8,000” estimates, no surprise line items later.
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Prep and protection. We cover your floors, mask off windows and doors, and seal off the work area so overspray doesn’t travel through the house. Our technicians wear full protective equipment and are background-checked, uniformed, and trained on every foam system we install. You’ll know exactly who’s in your home and why.
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Spray application. We apply foam to the specified depth, monitored in real time to ensure we hit the R-value we quoted. Temperature and humidity conditions affect foam curing, so we adjust application technique based on San Antonio’s specific climate conditions on installation day.
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Post-spray inspection and cleanup. We inspect every square foot of the application for gaps, thin spots, or improper adhesion. We run a second thermal scan to confirm the air seal is complete. Then we remove all masking, clean the work area, and walk you through exactly what we did and where.
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Documentation and Done Right Promise. You get a written record of the job: what product we used, what depth we sprayed, what R-value that delivers, and confirmation that the work carries our lifetime workmanship guarantee. If it’s not done right, we make it right. That’s the Done Right Promise, and it’s written into every job we do.
How Much Does Spray Foam Insulation Cost in San Antonio?
A typical open-cell attic spray foam job in San Antonio runs $4,000 to $7,000 for a 1,800 to 2,500 square foot home. Closed-cell foam on the roof deck or exterior walls costs more, usually $8,000 to $15,000 for the same house, because the material price per board foot is higher and the application is more involved. Rim joist sealing alone typically lands between $800 and $2,000 depending on home size and accessibility.
What affects the price: the square footage of the area being sprayed, the foam depth required to hit your target R-value, accessibility (crawl spaces and tight attics take longer), and whether we need to remove old insulation first. You can avoid overpaying by getting a board-foot breakdown on any quote you receive. That number is the honest metric: multiply board feet by the per-board-foot price, and that’s your material plus labor cost. We include this breakdown on every estimate we write. Our estimates are free, and if you already have a written quote from another San Antonio contractor, bring it in. We’ll give you a free second opinion on it, no charge and no pressure.
Spray Foam Insulation Near San Antonio - Our Service Area
We work throughout San Antonio and Bexar County, from Alamo Heights and Terrell Hills down to Helotes, Converse, and everything in between. Most San Antonio spray foam jobs are scheduled within 48 hours of the estimate, and smaller jobs like rim joist sealing can sometimes be done same-week. If you’re outside the immediate metro, call us at (866) 751-4428 and we’ll tell you straight up if we can get to you. If you’re near Spray Foam Insulation in Houston, Spray Foam Insulation in Spring, or Spray Foam Insulation in The Woodlands, those pages cover our work in those areas, and we run crews there regularly. We’re the one down the road, not an 800 number.
Serving San Antonio, TX - Our Local Coverage Area
We’re based in the San Antonio area and know this community well, and we also provide our Spray Foam Insulation in Houston. Use the map below to see our full service coverage - if you’re nearby, we can almost certainly help.
Frequently Asked Questions - Spray Foam Insulation in San Antonio
Spray foam insulation is a two-part liquid that expands on contact to fill cavities, seal air leaks, and create a continuous thermal barrier. It’s applied with specialized equipment and cures in minutes, unlike fiberglass batts or blown-in cellulose, which leave seams and gaps. Spray foam is the only insulation type that functions as both an insulator and an air barrier in one application.
Most whole-home spray foam jobs in San Antonio take one to two days on site. Preparation and masking take a few hours, the spray application itself moves quickly, and then the foam cures within minutes to hours depending on the product. You can typically be back in the house the same day or the next morning. Rim joist sealing alone is often done in under four hours.
Spray foam insulation in San Antonio runs $1.50 to $4.50 per board foot installed, with whole-home projects typically landing between $4,000 and $12,000 depending on scope and foam type. Open-cell attic work costs less, closed-cell roof deck and wall applications cost more. Call (866) 751-4428 for an exact quote on your square footage, and remember we offer a free second opinion on any written estimate you already have.
Yes, we install and work with spray foam systems from Icynene, Demilec, and CertainTeed, among others. Our crews are trained and certified on each manufacturer’s specific application requirements. If a previous contractor installed one of these systems and it’s underperforming, we can assess it and tell you what’s needed to fix it. Give us a call at (866) 751-4428 and tell us what you have.
Yes, we keep crews available for urgent San Antonio work: storm damage that exposed wall cavities, sudden pest intrusion through rim joists, or a failed foam application from another contractor that’s leaving your house exposed. Our phones are answered by a live person 24/7, so you’ll speak to someone who can actually get a crew dispatched, not a voicemail. If you need a same-day response, calling is the fastest path.
Every spray foam job we install carries our lifetime workmanship guarantee, the Done Right Promise. If the application fails, doesn’t perform as quoted, or otherwise isn’t done right, we make it right at no cost to you. On top of that, the manufacturers we use (Icynene, Demilec, CertainTeed) carry their own product warranties that we’ll register for you at installation.
Clear the attic access area and any rooms directly below the work zone, and move anything you don’t want dusted to another part of the house. We’ll handle full floor and surface protection, masking, and cleanup, but removing personal items from the immediate area speeds things up. If you have pets, plan to keep them in a separate room during application. We’ll walk you through everything else at the estimate.
Schedule Your Spray Foam Insulation Service in San Antonio Today
We’re the one down the road, and we’ve been doing this in San Antonio for 25 years. Call (866) 751-4428 for a free, no-obligation estimate with exact board-foot pricing, and a live person will answer, day or night. If you already have a quote from anyone else, we’ll give you a free second opinion on it. No trip charge in our service county. Seniors and veterans get 10% off, always.
Written by Walt Brenner, Owner at Walt’s Insulation, serving San Antonio since 2000.