Knauf Blown-In Insulation in San Marcos: What to Know First
We provide independent Knauf blown-in insulation service in San Marcos, typically scheduling within 48 hours and completing most attic jobs in a single day. Most homes we see run between $1,800 and $3,400 for a full Knauf blown-in fiberglass top-off with air sealing, or $2,600 to $4,800 for complete removal and replacement with fresh Knauf Jet Stream Ultra or Ecobatt blown-in material. We publish a written price before any work starts and hand you blower-door numbers when we leave, not promises.
This page is for San Marcos homeowners who already have Knauf insulation in their attic, walls, or crawl space and need to add more, replace what’s settled or damaged, or figure out why the house still runs the HVAC harder than it should. If you’re comparing bids or trying to match existing Knauf product, call (737) 337-8049. Estimates are free, and we’ll read a competitor’s written quote with you line by line.
How Knauf Products Fail - and How We Fix Them
- Jet Stream Ultra settling in San Marcos attics. This high-velocity blown-in fiberglass is engineered to fill to a labeled R-value at a specific installed density, but we regularly find it 15-20% below spec in homes near the Blanco River corridor where summer attic temperatures exceed 140°F and the material compresses faster than the product data sheet assumes. We remove the settled layer, air-seal the top plates and can-light penetrations that were skipped originally, then reinstall to manufacturer density with a depth marker strip left visible for verification.
- Ecobatt blown-in clumping from roof leaks. Knauf’s brown fiberglass uses a plant-based binder instead of phenolic formaldehyde, which performs well dry but mats into dense clumps when exposed to chronic drip from San Marcos’s wind-driven rain events, common in older neighborhoods between Hopkins Street and the railroad tracks. We don’t just add more insulation over the clumps; we cut out the damaged sections, map the leak source with photos, and replace with fresh Ecobatt only after the roofer or flashing repair is documented.
- InsulSafe SP thermal drift in wall cavities. This blown-in fiberglass product for sidewalls relies on friction fit against stud bays, but in San Marcos’s 1950s-1970s slab-on-grade stock near Texas State, irregular framing and missing fire blocking create voids we find with thermal imaging. We dense-pack to 3.5 pounds per cubic foot using a tube-and-fill method, or switch to Knauf’s Jet Stream MAX for walls if the cavity geometry demands it, always noting the product change on your written scope.
- Moisture accumulation in Knauf-insulated crawl spaces. San Marcos’s clay-heavy soils wick moisture upward, and when Knauf blown-in is installed in vented crawl spaces without a proper vapor barrier, the binder breaks down and the material sags off mesh supports. We encapsulate first with a 10-mil polyethylene barrier sealed to piers and walls, then reinstall only if the crawl space is conditioned or fully sealed, following the sequence we learned from years of fixing jobs where insulation went in before the moisture problem was solved.
- Compatibility gaps between Knauf and older Reflectix radiant barriers. Some San Marcos homes from the 1980s and 1990s have Reflectix stapled to rafters with Knauf blown-in underneath; the reflective surface needs an air gap to work, and adding more Knauf often eliminates that gap or compresses the existing layer. We assess whether the Reflectix stays, gets reinstalled with proper standoffs, or comes out entirely, documenting the decision and the before-and-after attic airflow with a blower-door test so you know whether the radiant barrier was doing anything worth keeping.
Our Knauf Blown-In Insulation Process
- 1
Call and scheduling. A live person answers, or you text (737) 337-8049. We book a 2-hour arrival window and send a text when the technician is en route.
- 2
Attic inspection and blower-door baseline. We run a blower-door test - a pressurization reading that shows, in one number, how much air your building envelope is losing. We photograph existing Knauf product labels where visible, measure settled depths, and mark thermal bypasses with smoke pencil.
- 3
Written price and scope. You get a flat price, written scope, and written warranty before anyone lifts a tool. Haven Standard Clause 1: no work starts without it. If you have a competing written estimate, we’ll read it with you.
- 4
Air sealing first, then insulation. We seal top plates, can lights, chimney chases, and duct penetrations with fire-rated caulk and foam. The R-value tells you how slow heat moves through the material - the blower-door number tells you whether any of that matters.
- 5
Knauf material selection and install. We match existing Knauf product where practical, or specify the upgrade with a note on why. Jet Stream Ultra for open attics, Jet Stream MAX for dense-pack walls, Ecobatt for homeowners prioritizing low binder emissions. We verify installed depth with marker strips.
- 6
Cleanup, documentation, and final test. We run the blower-door again, print the before-and-after CFM50 reading on a single page, and leave you with a Documented Photo Record of the work. The 365-Day Done Right Promise applies from that moment.
Before
AfterWhat Knauf Blown-In Insulation Costs in San Marcos
| Job Type | Typical Range | What Moves the Price |
|---|---|---|
| Knauf blown-in fiberglass top-off (attic, 1,200-2,000 sq ft) | $1,800 - $3,400 | Current depth, accessibility, amount of air sealing needed first |
| Full removal + replacement with Knauf Jet Stream Ultra | $2,600 - $4,800 | Existing material condition, rodent damage, deck repair for safe access |
| Dense-pack wall insulation with Knauf Jet Stream MAX | $3,200 - $5,500 | Wall area, siding type (brick vs. vinyl for access), cavity obstructions |
| Crawl space encapsulation + Knauf reinstall | $4,000 - $7,500 | Condition of existing vapor barrier, pier count, soil grading issues |
| Home energy audit with blower-door and thermal imaging | $350 - $550 | Home size; credited toward insulation work if we do the job |
These are real numbers for San Marcos homes we’ve worked on, not teaser rates. A 1,600-square-foot ranch near Wonder World Drive with settled Jet Stream Ultra and minimal air sealing runs toward the lower end. A 1970s two-story off McCarty Lane with clumped Ecobatt, skipped top plates, and a need for full deck work runs higher. Call (737) 337-8049 for your exact written price - estimates are free.
Why San Marcos Homeowners Call Topside Attic Insulation San Marcos for Knauf Work
We’ve sealed and insulated over 9,000 homes since 2016, and the ones that stick with us are the homeowners who read the three-star reviews as carefully as the five-star ones and want to see the number, not hear the pitch. Wes Okafor and our crew have worked San Marcos long enough to know which slab-on-grade neighborhoods have the skipped top plates, which attics near the university corridor run hot enough to accelerate fiberglass settling, and how to match existing Knauf product without locking you into a single brand if something else fits better.
We don’t ask you to trust us. We hand you a printed blower-door result, a photo record, and a written warranty. If it’s not done right, we make it right - 365 days, no voicemail loop to get there. We also carry Owens Corning, Johns Manville, Rockwool, CertainTeed, and other materials, so if your Knauf job is better served by a different product for a specific cavity or code requirement, we’ll say so and note it on the scope.
FAQs
No, adding compatible Knauf blown-in product does not void the original limited warranty, but mixing Knauf with incompatible materials or installing over unsealed air leaks can create coverage disputes if failure is traced to installation conditions rather than product defect. We document existing product labels and installation conditions with photos so there’s a clear record of what was there before we started. Call (737) 337-8049 if you want us to review your specific Knauf product documentation.
Usually yes for current Knauf lines like Jet Stream Ultra and Ecobatt blown-in; discontinued lines may require a close functional match with a note on the written scope explaining the substitution. We photograph existing product labels during inspection and cross-reference Knauf’s current availability before giving you the written price. If an exact match matters for your situation, tell us when you call (737) 337-8049.
Topping off is cheaper upfront - typically $800-$1,500 less for a standard attic - but only makes sense if the existing material is dry, uncompressed, and was installed over a properly sealed attic floor. We find that in San Marcos, especially in pre-1990 homes, the existing Knauf was often blown over unsealed top plates and can lights, which means the new layer performs below its labeled R-value no matter how deep we make it. We quote both options when we inspect and show you the blower-door number that explains which choice actually fixes your house.
Most Knauf attic jobs are scheduled within 48 hours of your call and completed in one day; dense-pack wall work or full removal with air sealing typically takes two days. We don’t manufacture urgency - we give you a real date, a named technician, and a text when they’re on the way. Call (737) 337-8049 to check current availability.
We use current Knauf manufactured product for all Knauf-specified jobs; for accessories like attic rulers, mesh netting, or specialized blowing adapters, we use quality aftermarket equivalents that meet the same performance specs and cost less, with any substitution noted on your written scope. We are an independent Knauf service provider, not a manufacturer-authorized dealer, so we have no obligation to use Knauf-branded accessories when a tested equivalent performs the same function at lower cost to you.
Ready to see what your attic is actually doing? Call (737) 337-8049 or text us to schedule a free estimate. We’ll run the blower-door test, show you the number, and give you a written price before any work starts - the Haven Standard, every time.
Written by Wes Okafor, Owner, Topside Attic Insulation San Marcos at Topside Attic Insulation San Marcos, serving San Marcos and nearby areas.