Fast, Reliable Spray Foam Insulation Across Terrell Hills
Spray foam insulation in Terrell Hills typically costs $2.50 to $6.50 per square foot installed, depending on whether you need open-cell or closed-cell foam, and most attic jobs in the 78209 zip code run between $1,800 and $6,200. Our crews reach Terrell Hills homes quickly, usually within a day or two of your call. That matters when a July afternoon pushes your upstairs bedrooms past 90 degrees. If you live in Terrell Hills and you’re tired of rooms that won’t hold temperature or utility bills that climb every August, call us at (361) 213-9499 for a written estimate before any work begins.
Why Aspen Attic Insulation San Antonio Is Terrell Hills’s Preferred Spray Foam Insulation Company
Terrell Hills is not an easy place to insulate badly well. The homes here were built before central air was standard, and the attics were framed for cedar shakes, not modern insulation. A crew that mostly works new construction in far northwest San Antonio will not know what to do with a 5 1/2-inch rafter bay on Garraty Road. Our technicians work these houses weekly. They know the shallow bays, the knob-and-tube wiring, the plaster ceilings that crack when you look at them wrong.
Every tech we send to Terrell Hills is background-checked, identity-verified, and arrives in a clean marked uniform with a photo ID badge. Before the visit, you get the technician’s name and photo sent to you. If anyone else shows up at your door, the visit is free and we make it right. That is the Threshold Standard, and we’ve operated under it since 2002.
We put the price in writing before work starts. Not a range on the phone, not an estimate that might move. A written price. And every job carries our 365-Day Done Right Promise: if it’s not done right, we make it right, in writing, covering labor and materials, with a free second visit if the repair fails.
Garage Spray Foam Insulation in Terrell Hills
Garage Spray Foam Insulation in Terrell Hills is one of the jobs we do most often on the detached garages that sit behind the 1920s and 1930s homes here, many of which were built as carriage houses with pier-and-beam foundations and no insulation at all. Homeowners call us when the garage becomes a workshop, a home gym, or a place to keep a classic car out of the heat. An uninsulated garage in Terrell Hills will hit 110 degrees by noon in August, and that heat bleeds into the house through the shared wall.
A typical detached garage ceiling and wall job in Terrell Hills runs $1,400 to $3,200, depending on square footage and whether you want open-cell foam for sound control or closed-cell for maximum R-value per inch. The roof deck on older garages here often has no ridge vent and undersized rafter bays, so we usually recommend spraying the underside of the roof deck directly, which converts the garage ceiling into a conditioned space without changing the roofline.
When a garage is attached to a 1920s home
Attached garages in Terrell Hills share a wall with the living space, and that wall is usually uninsulated masonry or wood frame with no cavity at all. Spraying that common wall with two inches of closed-cell foam cuts heat transfer and also helps with the exhaust smell that drifts into the house when a car is parked inside. We also spray the band joist where the garage ceiling meets the house wall, which is a common air leak point in these older homes.
What the job looks like on the day we arrive
We lay down floor protection inside the garage, seal the top plates, and mask anything that should not get foam on it. The spraying itself usually takes four to six hours for a two-car detached garage, and you can walk into the space the same evening. The foam cures hard within about 24 hours.
Closed Cell Spray Foam Insulation in Terrell Hills
Closed Cell Spray Foam Insulation in Terrell Hills is the product we recommend most often for the roof decks and exterior walls of the revival-style homes built between 1920 and 1950 here, because it delivers roughly R-6.5 per inch in a rafter bay that might only be 5 1/2 inches deep. Open-cell foam only gives you about R-3.7 per inch, so in a shallow bay it cannot hit code without filling the entire cavity to overflowing. Closed-cell fits the geometry of these houses.
A closed-cell roof deck job in Terrell Hills typically lands between $4.50 and $6.50 per square foot of sprayed surface. For a 1,200-square-foot attic with shallow bays, that usually means $5,400 to $7,800. It is not the cheapest option. It is the one that actually works in houses built with cedar shakes under the shingles and no room for fiberglass batts. Closed-cell also functions as an air barrier and vapor retarder, which matters in Terrell Hills’ humid summers, where open-cell foam on an unvented cathedral ceiling traps moisture against the plaster and causes the paint to blister along dormer walls.
Building code and vintage construction
San Antonio’s climate zone requires R-38 in vented attics and R-20 on unvented roof decks. A 5 1/2-inch rafter bay with closed-cell foam gets you to about R-36 at full depth, which is close enough that air sealing the top plates and adding a thin thermal barrier usually satisfies the performance requirement. We handle that conversation with the local code office so you do not have to.
Rim joist and band joist work in older homes
Pier-and-beam foundations are standard across Terrell Hills, and the rim joist is the single biggest air leak in those houses. We spray the rim joist from inside the crawl space with two inches of closed-cell foam, which stops the stack effect that pulls hot humid air into the house all summer. That job alone usually runs $900 to $1,600 and pays for itself in a couple of cooling seasons.
Trusted Brands We Service in Terrell Hills
We install and service spray foam systems from Demilec, Icynene, and CertainTeed, and we stock the materials locally so a Terrell Hills job does not wait on a shipment from Dallas. Each brand has different expansion rates, cell structures, and vapor perm ratings, and we match the product to the house rather than forcing whatever is on the truck. For the shallow rafter bays and plaster ceilings common in Terrell Hills, we typically reach for Demilec’s closed-cell formulations or Icynene’s open-cell for sound-control applications in interior walls and garage ceilings. We have worked with these systems long enough to know exactly how they cure in a 140-degree Terrell Hills attic in July.
Common Spray Foam Insulation Problems We See in Terrell Hills Homes
- Closed-cell foam sprayed too thin in shallow rafter bays. Some contractors spray an inch and a half and call it done. In Terrell Hills’ humid climate, that under-sprayed foam fails to hit code R-value and allows condensation to form on the underside of the roof deck, which quietly rots the original cedar shakes. We spray to the full depth the bay allows or we tell you it cannot be done.
- Open-cell foam on unvented cathedral ceilings. This is a moisture trap in Terrell Hills. Open-cell foam is vapor-permeable, so humid attic air passes through it and condenses against the plaster ceiling below. The result is paint blistering and mold along the dormer walls of 1930s colonials. Humid southern attics need closed-cell on unvented assemblies.
- Foam installed without mapping knob-and-tube wiring first. Many Terrell Hills homes still have original knob-and-tube conductors behind the plaster walls. Open-cell foam sprayed over those conductors insulates them and can cause overheating, which becomes a fire hazard. We inspect and map the wiring before any foam goes into a wall cavity.
- Standard fiberglass batts jammed into vintage rafter bays. This is the most common mistake in Terrell Hills. The bays are too shallow, so the batt compresses to nothing and leaves air gaps along the sides. Homeowners pay for insulation that does nothing. Spray foam expands into the full cavity and seals it.
Pricing for Spray Foam Insulation in Terrell Hills, TX
Here are the numbers we quote most often for Terrell Hills homes. An open-cell attic floor job runs $1.75 to $2.75 per square foot, so a 1,000-square-foot attic lands between $1,750 and $2,750. A closed-cell roof deck job in shallow rafter bays runs $4.50 to $6.50 per square foot, typically $5,400 to $7,800 for the average roof deck here. Rim joist work in a pier-and-beam crawl space usually runs $900 to $1,600. A detached garage conversion with closed-cell on the ceiling and common wall runs $1,400 to $3,200. The final price depends on square footage, bay depth, access, and whether we are air sealing top plates and mapping wiring. You get a written price before anything starts, and that price is the price. Call (361) 213-9499 for a free estimate with no obligation.
Spray Foam Insulation for Older Terrell Hills Homes
Terrell Hills has one of the most distinctive housing stocks in the San Antonio area. The homes along Garraty Road, Elizabeth Road, and Wiltshire Avenue were built in the 1920s and 1930s by architects who were copying English and Spanish revival styles, and they built them before insulation was code. Many still have plaster over wood lath, uninsulated exterior walls, knob-and-tube wiring, and attics with original cedar shakes visible under newer composition shingles. The rafter bays are shallow, often 5 1/2 inches. Standard fiberglass batts do not fit, and blowing loose fiber into those shallow bays leaves you with no air barrier and no real R-value. Spray Foam Insulation is the only product that fills those bays completely, air-seals them, and hits a useful R-value without dropping the ceiling or changing the roofline.
We were called to a 1930s stone-veneer colonial on Garraty Road where the attic was hitting 140 degrees in July. The rafter bays were only 5 1/2 inches deep, with original cedar shakes visible under the shingles. Our crew air-sealed the top plates and sprayed 4 inches of closed-cell foam directly against the roof deck, cutting the second-floor temperature swing by 18 degrees without changing the roof line or disturbing the original plaster ceilings. That is the kind of job a crew from outside the area will not even recognize, and it is exactly the kind of job we do in Terrell Hills several times a month.
Knob-and-tube wiring is the other complication. We map it before any foam goes in, because spraying open-cell foam over old conductors can overheat them and create a fire hazard behind period plaster walls. We do not skip that step, ever. A Terrell Hills house deserves insulation that works with the way the house was built, not against it.
We Also Serve Cities Near Terrell Hills
Our techs cover Terrell Hills and the surrounding communities, including Spray Foam Insulation in Terrell Hills, San Antonio, Schertz, Universal City, and Live Oak. If you live just outside Terrell Hills or have a rental property in the area, we can likely help. Call and ask. The person who answers is a live person, 24/7, and they can tell you if we serve your street.
Serving Terrell Hills, TX - Our Local Coverage Area
We’re based in the Terrell Hills 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 About Spray Foam Insulation in Terrell Hills
Yes, and it is the standard approach we recommend for these homes. Closed-cell spray foam is applied directly to the underside of the roof deck from inside the attic, so no roof removal is needed. In Terrell Hills’ 1920s and 1930s homes, the rafter bays are often only 5 1/2 inches deep, which is too shallow for fiberglass batts. Closed-cell foam at about R-6.5 per inch gets the assembly close to code R-value without altering the roofline. Call (361) 213-9499 and we can tell you what your specific attic can take.
Spray foam can be safely installed in homes with knob-and-tube wiring, but only if the wiring is mapped and addressed first. The risk comes from spraying foam over live knob-and-tube conductors, which can overheat when insulated. Our crew on a Terrell Hills job maps every wall and ceiling cavity for old wiring before we spray, and if we find active knob-and-tube, we will tell you before we do anything else. This is not a corner we cut.
You prevent condensation by using closed-cell spray foam at the correct thickness and by air sealing all top plates and penetrations before spraying. In Terrell Hills, where summer humidity routinely sits above 70%, open-cell foam on an unvented assembly is the wrong product. It allows humid air to pass through to the cold side and condense. Closed-cell foam acts as a vapor retarder and air barrier, which is what these vintage homes need. Call us at (361) 213-9499 and we can assess your specific roof assembly.
No, spray foam does not touch the plaster. For roof deck applications we spray the underside of the roof sheathing from inside the attic, so the plaster ceilings below are not disturbed at all. For wall cavities we access them either through the attic or from small drilled holes in interior or exterior surfaces, and we patch those cleanly. The expansion of closed-cell foam is controlled and does not crack plaster. We work around original plaster and lath in Terrell Hills homes constantly, and the 365-day promise covers any repair if something does go wrong.
Spray foam works well in detached garages on pier-and-beam foundations, and it is one of the most common jobs we do in Terrell Hills. We spray the ceiling deck and the common wall, and we seal the rim joist from the crawl space side to stop the stack effect. A typical detached two-car garage in Terrell Hills runs $1,400 to $3,200 for a full closed-cell ceiling and wall application, and the space becomes usable year-round.
Get a Written Quote for Spray Foam Insulation in Terrell Hills
If your Terrell Hills home still has original plaster, shallow rafter bays, a cedar shake history, or a utility bill that climbs every month, we can help. Garrett Sloane leads our team, and he will make sure you know exactly who is coming to your door, what they will do, and what it will cost before anything begins. That is the way we have worked since 2002. Call (361) 213-9499 today and get a free, written estimate with no pressure and no surprises. The person who answers is a live person, and they will get you scheduled.
Written by Garrett Sloane, Owner at Aspen Attic Insulation San Antonio, serving Terrell Hills homeowners with spray foam insulation that respects the construction and the character of their homes.