San Marcos sits where the Blanco River cuts through the limestone hills, mixing historic homes near the water with student housing, new subdivisions, and the sprawl of I-35 development. Your house is likely built on a concrete slab or on pier-and-beam over a crawl space, with ductwork and water lines running through a vented attic that hits 140 degrees on a 100-degree summer day. That attic is the biggest energy leak in your home, and it is the reason your cooling bill climbs every June.
Austin Spray Foam Insulation has been sealing attics, walls, crawl spaces, and metal buildings across the Austin area since 2012. We know San Marcos construction, the Balcones Escarpment terrain, and the brutal summers and occasional hard freezes that test every insulation job. When your bonus room won't cool, your attic smells musty, or your condensation is dripping on your garage floor, we show up with a truck and a crew that knows what to fix and how to price it honestly.
Spray Foam Insulation in San Marcos (78666)
San Marcos homeowners face real insulation challenges that generic blown-in fiberglass cannot solve. If your house was built before 1980, your attic insulation is likely compressed, rodent-fouled, or missing altogether. If it was built between 1950 and 1970, your walls are empty cavities with no insulation at all. Either way, your ductwork is running through unconditioned space, and your air conditioning is working against the heat load of a vented attic that reaches 160 degrees in July and August. Closed-cell spray foam stops that heat transfer at the roof deck and seals every air leak at once. In crawl spaces under pier-and-beam homes, open-cell foam lets the structure breathe while it stops the humidity and condensation that rot wood and corrode metal. In metal buildings and barndominiums scattered across the Hill Country around San Marcos, closed-cell foam is the only material that will not sweat in the Texas heat and humidity.
We have been installing spray foam insulation in San Marcos and across Greater Austin for over a decade. We know which jobs need closed cell and which need open cell. We know when the insulation has to come out first, and we know how to price that removal honestly. We pull written estimates with R-value and thickness specifications so you know exactly what you are paying for and what the code requires at your address.
Our services in San Marcos
- Attic Spray Foam Insulation in San Marcos · Open-cell foam on the roof deck turns a 150°F Austin attic into conditioned…
- Closed Cell Spray Foam Insulation in San Marcos · Two-pound closed-cell foam delivers R-6.5 per inch with its own vapor retarder…
- Open Cell Spray Foam Insulation in San Marcos · Half-pound open-cell foam air-seals attics and walls at a friendlier price per…
- Wall & Injection Foam Insulation in San Marcos · Injection foam fills closed walls through small drilled ports, no demolition.
- Crawl Space Spray Foam Insulation in San Marcos · Closed-cell foam on pier-and-beam subfloors and crawl space skirts stops cold…
- Rim Joist & Band Joist Spray Foam in San Marcos · Band joists; cantilevers and bonus-room floors over garages leak conditioned…
- Garage Spray Foam Insulation in San Marcos · Garage ceilings under bonus rooms and walls shared with the house are…
- Metal Building & Barndominium Spray Foam in San Marcos · Closed-cell foam is the insulation that stops a Texas metal building from…
- Commercial & New Construction Spray Foam in San Marcos · Warehouses; offices; churches and production builders served on schedule.
- Insulation Removal in San Marcos · Old blown-in and batts vacuumed out before any new foam goes in, never buried.
- Insulation Replacement & Re-Insulation in San Marcos · The full reset: old material removed; gaps air-sealed…
- Air Sealing in San Marcos · Top plates; can lights; chases and attic hatches leak more cooled air than most…
How a Job Works in San Marcos
We start with a free on-site assessment. We walk your attic, crawl space, or garage with you, measure the area to be sprayed, check what is already there, and explain what has to happen before foam goes down. If your old insulation is wet, compressed, or contaminated, we quote the removal first. We do not spray over a bad substrate. If your attic has active roof leaks or your crawl space has standing water, we tell you plainly that the moisture has to be fixed first or we walk away. That honesty is itself the expertise signal.
On the day of the job, our crew brings mechanical ventilation and sets up a containment zone. We spray the foam at the manufacturer ratio and drum temperature, building thickness in controlled passes so the material cures properly and does not off-gas for weeks. You will smell the application, and that is normal. We tell you up front: the space is not safe to re-enter until the foam has cured, typically twenty-four to forty-eight hours depending on thickness and ambient temperature. We leave your property clean, remove our equipment, and give you a final walkthrough so you see what we sprayed and where.
Spray foam pricing in San Marcos depends on the area to be covered, the R-value and thickness you need, whether you choose open-cell or closed-cell foam, and what has to be removed first. A typical attic spray foam job in San Marcos starts around $1.50 per square foot for open-cell foam applied to the roof deck. Wall injection foam for a 1950s ranch with empty cavities runs roughly $2 per square foot. A crawl space encapsulation with closed-cell foam on the rim band and open-cell on the floor typically starts at $2,500. Removal of old, damaged insulation runs from $950 depending on volume. These are ballpark figures. The only way to know the real cost for your house is to have us measure it on site and give you a written estimate with the R-value, thickness, and square footage spelled out. Call us at (737) 404-4885 for a free estimate. We will walk your property, answer your questions, and give you a price you can trust.
✅ Written Estimates with R-Value & Thickness Specs, fully insured for work in San Marcos and nearby areas.
