Trusted Spray Foam Insulation for San Antonio Homeowners
If you’re wondering how much Spray Foam Insulation costs, San Antonio prices typically run $2.50 to $6.50 per square foot installed, depending on whether you choose open cell or closed cell foam, and most whole-attic projects fall between $5,000 and $12,000 after all prep work and clean-up. Thistledown Insulation San Antonio has served Bexar County homes since 2003 as part of the Cedarwell family, and our crews handle everything from rim joists to full attic applications with a written price before any work begins. Neil Barron leads our local team, and we answer the phone live at (903) 437-9164 any hour, any day, when a San Antonio attic needs attention.
What separates us from a typical insulation crew comes down to how we treat your house. We lay drop cloths across your hallway, wear shoe covers from the front door to the attic hatch, and use quiet tools when the baby is napping. Before our van pulls away, you’ll have a photo of the clean-up and a 365-Day Done Right Promise behind every square inch of foam we installed.
Closed Cell Spray Foam Insulation
Closed Cell Spray Foam Insulation is a dense, rigid foam that acts as both an insulator and a moisture barrier, which makes it the right choice for San Antonio homes dealing with humidity, flood-zone crawl spaces, or metal buildings where condensation is a concern. Thistledown Insulation San Antonio installs closed cell foam from Icynene and Demilec, and closed cell projects in San Antonio typically run $3.50 to $6.50 per square foot depending on depth, access, and surface area. The higher cost per inch comes with a higher R-value, roughly R-6.5 to R-7 per inch, so even a 2-inch layer changes how a room feels in August.
When Closed Cell Makes Sense
Homes in areas like Alamo Heights or Terrell Hills with unvented attics, ductwork in unconditioned space, or a history of musty smells benefit most from closed cell’s air and moisture sealing. We see it specified often for rim joists and crawl space encapsulation in San Antonio’s older pier-and-beam homes.
Because closed cell adds structural rigidity, it’s also a smart pick for garage conversions, storage buildings, and any space where the framing needs a little extra stiffness alongside insulation.
Our Closed Cell Install Standards
We never rush a closed cell job. Proper temperature and substrate prep matter, and our uniformed, background-checked technicians follow the manufacturer’s spec on every pass, not just the fast version that looks fine on day one.
Every closed cell project gets the same written price before work starts and the same 365-Day Done Right Promise after, so you know the R-value we quote is the R-value you keep.
Open Cell Spray Foam
Open Cell Spray Foam is a lighter, softer foam that expands dramatically after application, making it a strong fit for attic rooflines and interior walls where air sealing matters more than moisture blocking. Thistledown Insulation San Antonio uses open cell products from Icynene and Demilec in San Antonio homes, with typical open cell attic projects ranging from $2.50 to $4.00 per square foot for a full roofline application. Because it’s less expensive per inch than closed cell, homeowners who want the air-sealing benefit of foam without the denser product’s price tag often choose open cell for unconditioned attics.
Where Open Cell Works Best
Vented attics in San Antonio neighborhoods like Kirby and Leon Valley are a common spot. We apply open cell to the attic floor or roofline to cut air leakage, which is what drives the biggest chunk of cooling loss in a Texas summer.
Open cell also handles sound well, so walls between a nursery and a home office or a media room and the rest of the house get quieter with an open cell fill.
Open Cell and San Antonio’s Climate
San Antonio’s humidity levels mean open cell needs proper ventilation planning, and we’ll walk you through exactly how your attic’s airflow design interacts with the foam before we quote a single square foot.
Our written price covers the prep, the spray, the trim, and the clean-up, including drop cloths and shoe covers from the first step inside your home to the final photo of the finished job.
Spray Foam Insulation Contractors
Spray Foam Insulation Contractors are the licensed crews who install foam insulation, and choosing the right one in San Antonio means finding a team that shows up when they say they will, protects your floors, and gives you a real number before work starts, which is exactly how Thistledown Insulation San Antonio has operated since 2003. Our technicians are background-checked and uniformed, so you always know who is walking through your door. We install products from Icynene and Demilec, and as a Cedarwell-family company, every visit follows the Cedarwell Care Promise: shoe covers on, drop cloths down, and a photo of the clean-up before we leave.
What to Expect From Our Crews
You’ll get a phone call before we arrive, a walkthrough of the work area before the hose comes off the truck, and a straightforward explanation of how long the foam needs to cure before your family can be back in the space.
If the dog is home during the job, we’ll point out which products are pet-safe and where we’ll keep the equipment so paws and foam never meet.
Why We Write the Price First
Most insulation contractors in San Antonio quote a range and hope the final bill lands somewhere inside it. We don’t. Your written price comes before any tool touches your home, and that number is what you pay unless you change the scope.
Neil Barron set that standard for our San Antonio team, and it’s backed by the 365-Day Done Right Promise: if the job isn’t done right, we make it right.
Spray Foam Attic Insulation
Spray Foam Attic Insulation seals the attic against San Antonio’s heat and humidity, typically applied to the roofline or attic floor, and it costs between $4,000 and $11,000 for most single-family homes in Bexar County depending on square footage and foam type. Thistledown Insulation San Antonio has insulated attics across the city since 2003, from Cibolo to Castle Hills, and we’ll tell you whether open cell or closed cell matches your attic’s ventilation design before we quote anything. The goal is simple: a cooler second floor in July and a lower cooling bill every month after.
Before We Spray Your Attic
We inspect the roofline, check for existing air leaks around can lights and plumbing vents, and test the attic’s ventilation so we know the foam will perform the way it should in a San Antonio attic that hits 140 degrees in August.
If you have ductwork in the attic, we’ll walk you through how foam at the roofline changes the temperature around those ducts, which is often the single biggest energy win in a Texas home.
Attic Prep and Clean-Up
Drop cloths go down on the hallway floor, shoe covers go on at the front door, and the attic hatch gets sealed off while we spray so dust and foam particles stay out of your living space.
When we finish, you’ll have a photo of the attic and the clean-up before our van leaves your street in San Antonio.
Spray Foam Wall Insulation
Spray Foam Wall Insulation fills wall cavities with expanding foam to stop air movement and add R-value, and for San Antonio homes it typically runs $1.50 to $4.00 per square foot of wall area depending on whether we’re working in new construction framing or retrofitting existing walls. Thistledown Insulation San Antonio uses open cell foam from Icynene and Demilec for most wall applications, because open cell’s expansion fills odd-shaped cavities and gaps that batt insulation leaves behind. Exterior wall spray foam is one of the best ways to cut drafts in older San Antonio homes around Alamo Heights and Terrell Hills where the original insulation has settled or was never enough.
New Construction Walls
If you’re building in Cibolo or Timberwood Park, we coordinate with your builder for our Spray Foam Insulation in Cibolo before drywall goes up, which is the easiest and most complete way to insulate a new home in San Antonio.
Open cell in a 2×4 or 2×6 wall gives you continuous air sealing, and we can quote both thicknesses so you can compare R-value per dollar before you decide.
Retrofit Wall Insulation
Existing walls are trickier, and we’ll be honest about whether spray foam from the interior or a drill-and-fill approach from the exterior makes more sense for your home’s construction.
Whatever the method, the same rules apply: written price first, drop cloths and shoe covers during, and a photo of the clean-up before we go.
Rim Joist Spray Foam
Rim Joist Spray Foam seals the band board where your floor framing meets the foundation, a spot where San Antonio homes lose conditioned air and let bugs, dust, and humidity inside, and this service typically costs $1,200 to $3,000 for a full perimeter treatment in a standard slab or crawl space home. Thistledown Insulation San Antonio uses closed cell foam from Demilec for rim joists because the moisture resistance and air sealing are exactly what that vulnerable band of framing needs. It’s one of the highest-value insulation projects we do, especially in older pier-and-beam homes around Leon Valley and Spray Foam Insulation - Floresville.
What Rim Joist Foam Fixes
Cold drafts near baseboards in winter, warm humid air sneaking in during summer, and the musty smell that comes from dirt-floored crawl spaces all trace back to unsealed rim joists in many San Antonio homes.
Closed cell foam at the rim also blocks the path mice and roaches use to get from the crawl space into your walls, which is a real concern in Bexar County’s older neighborhoods.
How We Treat Rim Joists
We access the rim from the crawl space or basement, clean the surface, and spray a continuous bead of closed cell foam across every joist bay, not just the obvious gaps.
The job is done in a day in most San Antonio homes, and the same written-price rule applies: you’ll have your exact number before we spray anything.
Crawl Space Spray Foam Insulation
Crawl Space Spray Foam Insulation seals the underside of your home against ground moisture and outside air, and in San Antonio it typically runs $4,000 to $9,000 for a full encapsulation-grade application on an average pier-and-beam house. Thistledown Insulation San Antonio uses closed cell foam from Demilec or Icynene on crawl space walls and rim joists in homes across Bexar County, because closed cell is the product that actually stops moisture migration from the soil. A sealed crawl space means fewer musty smells, lower humidity inside the house, and floors that don’t feel cold in January.
Crawl Space Conditions We See in San Antonio
San Antonio’s clay soil holds water through wet springs, and that moisture rises into the crawl space and straight into your floor framing. We see rotted rim boards and sweating ductwork regularly in homes from Floresville to Castle Hills.
Closed cell foam applied to the crawl space walls and rim creates a thermal and moisture break that changes how the whole first floor feels and smells.
What a Crawl Space Job Includes
We’ll inspect the space, check for standing water or drainage problems that need addressing first, and give you a written price that includes prep, foam, and clean-up.
Because we’re working below your home, not inside it, we’ll still protect the access point with drop cloths and leave you a photo of the finished crawl space when the job is done.
Garage Spray Foam Insulation
Garage Spray Foam Insulation seals the walls and ceiling of an attached or detached garage to keep it from turning into a furnace in the San Antonio summer, and a typical two-car garage runs $1,800 to $4,500 depending on whether we foam just the shared wall or the entire space. Thistledown Insulation San Antonio has insulated garages all over the city, from Lackland AFB housing to newer builds in Cibolo, using open cell foam from Icynene for walls and ceilings where moisture isn’t a concern. If your garage shares a wall with the living room or a bedroom above it, insulating that space changes how those rooms feel from the first hot day after the job.
Shared Wall and Ceiling Treatments
The wall between your garage and your house is often the least insulated surface in the entire home, and in San Antonio it gets blasted by heat radiating off the garage door and the concrete slab every afternoon.
We’ll foam that shared wall and the garage ceiling if there’s living space above, and you’ll notice the difference in the bedroom over the garage within days.
Full Garage Conversions
If you’re turning a garage into a workshop, gym, or extra living space in San Antonio, spray foam on the garage door walls and ceiling makes the room usable year-round, which no amount of portable AC can do on its own.
The written price and 365-Day Done Right Promise apply to garage jobs just like every other project we take on.
Brands We Service
We install spray foam insulation from Icynene and Demilec, two brands we’ve trusted for years because their products hold up in San Antonio’s heat and humidity cycle. Icynene’s open cell foam expands consistently in wall cavities and attic rooflines, and we’ve used it in homes from Kirby to Timberwood Park where air sealing was the primary goal. Demilec’s closed cell line gives us the moisture resistance and structural strength we want for rim joists and crawl spaces in Bexar County’s pier-and-beam homes.
Where a pet-safe product choice exists, we’ll point it out before the job starts, so families with dogs or cats know exactly what’s going into their walls and attic. Whether your San Antonio home calls for Icynene, Demilec, CertainTeed, or GreenFiber, we’ll match the right product to the right space and never push a brand that doesn’t fit the job.
Signs You Need a Pro Right Now
- Your upstairs rooms won’t cool below 80 degrees in summer. San Antonio attics hit 140 degrees by mid-afternoon, and if the insulation at the attic floor or roofline is thin or missing, that heat pours straight down through the ceiling. A pro can measure what’s there and tell you exactly where the gaps are.
- You feel a draft near baseboards or electrical outlets. Air leaking through rim joists and wall cavities feels like a breeze on windy days, and it carries humidity from the crawl space or outside right into your living room. Spray foam seals those paths, which no amount of caulk can fully fix.
- Your energy bills climb every summer even though the thermostat never moves. Rising cooling costs with the same settings usually mean the air you paid to cool is escaping through the attic or rim joists. Sealing those leaks with foam is the fix that keeps paying for itself.
- You smell mildew or dampness near the crawl space or garage. Musty odors in a San Antonio home often mean crawl space moisture is wicking up into the floor framing, and closed cell foam is the product that stops that cycle. The smell is a symptom, not the problem.
- Pests keep finding their way into the walls. Mice, roaches, and crickets in San Antonio take the same path into your house that your air takes out: gaps at the rim joist, sill plate, and around pipes. Closed cell foam blocks those entries while it insulates.
Our Process, Step by Step
1. Phone Call and Honest Questions
You call (903) 437-9164 and talk to a live person, not a voicemail tree. We ask about your home’s age, the rooms that feel uncomfortable, and any moisture or pest issues you’ve noticed, then we schedule a time to look.
2. The On-Site Walkthrough
A uniformed, background-checked technician comes to your San Antonio home, puts on shoe covers at the door, and inspects the attic, crawl space, rim joists, or walls. We bring an infrared thermometer and moisture meter so we can point to exactly where air and humidity are getting in.
3. Your Written Price
Before any foam is sprayed, you get a written price that covers prep, material, labor, and clean-up. That number is what you pay, and it doesn’t change unless you ask us to add scope.
4. Prep and Installation
We lay drop cloths across every path we’ll walk, seal off the work area, and use quiet tools when children are sleeping. If the dog is home, we’ll tell you which products are pet-safe and where we’ll be working so everyone stays comfortable.
5. Clean-Up Photo and the Done Right Promise
Before our van leaves, we clean the work area, take a photo of the finished insulation and the clean-up, and walk you through what we did. Every job carries the 365-Day Done Right Promise: if it’s not done right, we make it right.
How Much Does Spray Foam Insulation Cost in San Antonio?
A typical open cell attic insulation project in San Antonio runs $5,000 to $9,000 for a 1,500 to 2,500 square foot attic, while closed cell foam on the same space runs $8,000 to $13,000 because the material costs more per board foot. Rim joist sealing alone usually lands between $1,200 and $3,000, and a full crawl space encapsulation with closed cell foam ranges from $4,000 to $9,000 depending on access and square footage. Wall insulation in new construction runs $1.50 to $4.00 per square foot of wall area, and garage projects typically fall between $1,800 and $4,500.
What changes the price: square footage, foam type, how easy the attic or crawl space is to access, and whether existing insulation needs to be removed first. San Antonio homes with steep rooflines, very low crawl spaces, or old blown-in insulation that needs extraction will land on the higher end. The way to avoid overpaying is to get a written number before work starts and to ask what’s included in that number, because some San Antonio contractors quote the foam but leave the prep and clean-up as a surprise on the final bill. Our free estimate walks you through every line item, and the price we write down is the price you pay. Call (903) 437-9164 to schedule yours.
Our Service Area Near San Antonio
Thistledown Insulation San Antonio serves homeowners across Bexar County and the surrounding communities, including Spray Foam Insulation in New Braunfels, Spray Foam Insulation in Boerne, Cibolo, Kirby, Floresville, Terrell Hills, Timberwood Park, Alamo Heights, Castle Hills, Lackland AFB, and Leon Valley. Most San Antonio appointments can be scheduled within a few days, and our crews are on the road across the metro area every week. If you’re not sure whether we cover your neighborhood, call (903) 437-9164 and ask.
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.
Frequently Asked Questions About Spray Foam Insulation in San Antonio
Spray foam insulation is a liquid foam that expands on contact and hardens into an air-sealing insulation layer, available in open cell and closed cell varieties. Thistledown Insulation San Antonio installs both types from Icynene and Demilec, depending on the space and what the home needs. It’s different from fiberglass or cellulose because it stops air movement, not just heat transfer. Call (903) 437-9164 and we’ll tell you which type fits your San Antonio home.
Most San Antonio attic, rim joist, or crawl space spray foam jobs take one day, and garage or wall projects often finish in half a day. Closed cell foam is typically ready to walk past within a few hours, though we’ll give you an exact re-entry time based on the product and thickness. Your written quote includes the timeline before we start. Call (903) 437-9164 to schedule a walkthrough.
Spray foam insulation in San Antonio costs $2.50 to $6.50 per square foot installed, with whole-attic projects ranging from $5,000 to $12,000 depending on foam type and home size. Rim joist work runs $1,200 to $3,000, crawl spaces $4,000 to $9,000, and garages $1,800 to $4,500. The best way to get an exact number is a free on-site estimate from Thistledown Insulation San Antonio at (903) 437-9164, and the price we quote is the price you pay.
Yes, we install Icynene and Demilec spray foam products in San Antonio homes, and we match each product to the specific space it’s going into. Open cell Icynene works well for attic rooflines and interior walls, while Demilec’s closed cell line is our choice for rim joists and crawl spaces. We’ll tell you which brand fits your home and why. Call (903) 437-9164 to ask about your specific project.
We answer the phone live at (903) 437-9164 24 hours a day, 7 days a week, and we’ll get a technician to your San Antonio home as quickly as the schedule allows for urgent situations like a major air leak or water-damaged insulation. Emergencies like a burst pipe that soaked your insulation need fast attention, and we’ll help you plan the right next step. Call any hour and you’ll talk to a person.
Every spray foam job from Thistledown Insulation San Antonio is backed by the 365-Day Done Right Promise, which means if the work isn’t done right within a year, we make it right without debate or fine print. The foam products we install also carry manufacturer warranties from Icynene and Demilec. Your written estimate spells out exactly what’s covered. Call (903) 437-9164 to learn more.
You don’t need to do much. We’ll ask you to clear a path to the attic hatch or crawl space access and move any fragile items away from the work area, then our crew handles the rest with drop cloths and shoe covers. Pets can stay home, and we’ll tell you which products are pet-safe where a choice exists. Call (903) 437-9164 and we’ll walk you through the prep list for your specific job.
Schedule Your Spray Foam Insulation Service in San Antonio Today
Call (903) 437-9164 and talk to a live person about your San Antonio insulation project. We’ll schedule a walkthrough, put a written price in your hands before any work starts, and back the finished job with our 365-Day Done Right Promise. Estimates are free, and there’s never pressure to decide on the spot.
Written by Neil Barron, Owner at Thistledown Insulation San Antonio, serving Bexar County since 2003.