Trusted Attic Air Sealing for Seguin Homeowners
Attic air sealing in Seguin typically costs $1,200-$3,800 for a complete job, and most homes we work on show a 30-50% reduction in air leakage measured by blower-door test. We’re Topside Attic Insulation Seguin, independently owned and operated under The Haven Standard since 2016, and we’ve sealed and insulated more than 9,000 homes with a written price before any work starts and a documented record when the crew leaves. If you’re seeing high summer electric bills, rooms that won’t stay cool, or dust collecting faster than it should, the problem is probably air moving through your attic floor faster than your insulation can stop it. Call us at (830) 549-6646 - a live person answers 24/7, and we can usually get to Seguin homes same day or next day.
What Our Attic Air Sealing Service Includes
Attic Floor Air Sealing
The attic floor is the largest single surface where conditioned air escapes into unconditioned space. In Seguin’s older neighborhoods like Kingsbury and McQueeney, we regularly find original construction with gaps around electrical boxes, plumbing chases, and partition walls that were never sealed before insulation was blown in decades ago. We use expanding foam, rigid foam board, and acoustic sealant to close every penetration, then verify with a blower-door test - a pressurization reading that shows, in one number, how much air your building envelope is losing. We won’t install new insulation over an unsealed attic floor; that’s Haven Standard policy, not an upsell.

Top Plate & Penetration Sealing
Top plates are the horizontal framing members where interior walls meet the ceiling, and they’re rarely sealed in production-built Seguin homes from the 1980s through the early 2000s. Each stud bay creates a chimney effect that pulls conditioned air upward year-round, which is why second-story rooms in places like River Plantation and Oak Village often run 8-12 degrees warmer than the thermostat setting. We remove existing insulation in work zones, seal every top plate joint with fire-rated foam or caulk depending on code requirements, and photograph each stage for your Documented Photo Record. This is the detail work that separates actual air sealing from insulation contractors who just blow more product on top of the problem.

Can Light & Duct Boot Sealing
Recessed can lights and HVAC duct boots are the most common large leaks we find in Seguin attics, especially in homes built during the 1990s and 2000s when airtight IC-rated fixtures weren’t standard. A single unsealed can light can leak as much air as a 6-inch hole in your wall, and duct boots - the metal connections where flex duct meets your ceiling - often pull completely loose from vibration and thermal cycling. We install fire-safe covers over non-IC cans, seal IC-rated fixtures with gasketed trim kits, and reconnect or replace duct boots with mastic-sealed mechanical connections. Every repair is photographed and noted in your written scope.

Attic Hatch Sealing
The attic hatch is the only intentional hole in your thermal envelope, and in most Seguin homes it’s built like an afterthought - a piece of drywall or plywood sitting on a frame with no weatherstripping and no insulation on the back. We build or install insulated hatch covers with compression seals, add latch hardware to maintain contact pressure as materials age, and verify with smoke-pencil testing that the seal holds under blower-door conditions. If your hatch is in a hallway or closet, this single repair often eliminates the draft you feel every time you walk past it.

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.
Signs You Need Attic Air Sealing Right Now

- Your upstairs rooms won’t stay within 3 degrees of your thermostat setting. In Seguin’s climate, with attic temperatures reaching 140°F in July, unsealed top plates and duct chases act like conveyor belts moving heat into your second floor. If your AC runs constantly from 2 PM to sunset and the upstairs still feels sticky, the building envelope is the problem, not the equipment size.
- Your summer electric bill exceeds $280 for a home under 2,500 square feet. We’ve reviewed utility bills from hundreds of Seguin homes, and the pattern is consistent: houses with sealed attics and proper insulation use 25-40% less cooling energy than comparable unsealed homes. If your neighbor’s bill is $180 and yours is $340 for the same square footage, air leakage is the likely difference.
- You feel drafts from ceiling fixtures, outlets, or baseboards on interior walls. That air isn’t coming from outside directly; it’s being pulled through your attic by the stack effect, then down through any path it can find. In older Seguin neighborhoods like Weinert and Mill Creek, we’ve traced drafts to gaps in top plates that were hidden by original insulation for decades.
- Your blown-in insulation has dark streaks or gray discoloration. Those streaks are dust and particulate matter that air has filtered through the insulation, exactly like a coffee filter. Clean insulation is a sign of minimal air movement; dirty insulation proves air is moving through it constantly, carrying away your conditioned air and your money.
- Your HVAC filter clogs faster than 60 days. When your attic pulls return air through leaks in the ceiling, it also pulls attic dust, fiberglass particles, and in some cases rodent debris into your breathing air. If you’re changing filters monthly and the old ones look gray rather than just dusty, your duct system and attic floor need inspection.
Before
AfterOur Attic Air Sealing Process - Step by Step
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Written price and scope before anyone enters your attic. We inspect accessible areas from the attic hatch, take thermal images of your ceiling from inside the living space, and present a flat price with a written scope and written warranty before any work starts. This is Haven Standard Clause 1, and it’s how we’ve operated since 2016.
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Blower-door baseline test. We set up the blower door - a calibrated fan mounted in an exterior door frame that depressurizes your house to measure total air leakage. The reading is recorded in CFM50, cubic feet per minute at 50 Pascals of pressure difference. Most unsealed Seguin homes built 1990-2010 test between 3,500 and 6,000 CFM50; we record your exact starting number.
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Systematic air sealing with photo documentation. Our technicians work in zones, removing insulation only where needed, sealing every penetration with appropriate materials, and photographing each repair. You receive these photos in your Documented Photo Record, not available on request - included on every job, no exceptions.
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Blower-door verification test. After sealing is complete, we run the blower door again and record the new CFM50 reading. Most Seguin homes show a 30-50% reduction; we publish both numbers on your invoice so you can verify the performance change you paid for. If the reduction falls short of our projected range, we find the remaining leaks before we leave.
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Written completion record and 365-Day Done Right Promise. You receive a final document with before-and-after blower-door numbers, photo documentation, materials used, and our written warranty. If anything isn’t done right, we make it right - backed by a real promise, not a feeling.
How Much Does Attic Air Sealing Cost in Seguin?

Most complete attic air sealing jobs in Seguin run $1,200-$3,800 depending on attic square footage, accessibility, and how many penetrations need sealing. Here’s how typical scenarios break down:
- Partial sealing (hatch + can lights + major duct boots): $800-$1,500. Common in newer Seguin homes where the attic floor was reasonably well-sealed at construction but fixtures and duct connections have failed.
- Standard whole-attic sealing (floor, top plates, penetrations, hatch): $1,800-$2,800. Typical for 1,800-2,800 square foot homes in neighborhoods like Zipp, Geronimo, and Seguin city limits built 1985-2010.
- Complex sealing (multiple attic zones, vaulted ceilings, extensive duct repair): $3,000-$3,800+. Found in larger custom homes near Lake McQueeney or properties with additions where multiple rooflines create complicated attic geometry.
What moves the price: attic accessibility (steep roof pitches or limited hatch size add labor), quantity of can lights and duct boots, whether existing insulation must be removed and replaced, and whether we find disconnected or deteriorated ductwork that needs repair before sealing is meaningful. We don’t seal over problems and call it done - that’s why we publish blower-door numbers.
How to avoid overpaying: get any competing quote in writing, then bring it to us for a Free Second Opinion. We’ll read it with you line by line and explain what’s actually being proposed. Many Seguin homeowners have shown us quotes for “attic sealing” that was just a thin layer of new insulation over untouched leaks. Under Haven Standard, our written scope specifies every sealing location and material; if it’s not in writing, it’s not in the price.
Your free estimate includes the blower-door baseline test, thermal imaging, attic inspection, and a written price valid for 30 days. Call (830) 549-6646 to schedule - estimates are free, and there’s no obligation to proceed.
Attic Air Sealing Near Seguin - Our Service Area
We serve Seguin and surrounding communities with typical response times of same day to 48 hours depending on season and scheduling. Our regular service area includes New Braunfels, Cibolo, Schertz, Universal City, Selma, Converse, Live Oak, Windcrest, Kirby, Canyon Lake, Terrell Hills, and all of Guadalupe County. Homes in New Braunfels and Cibolo often share the same construction era and climate conditions as Seguin, so our diagnostic approach translates directly. If you’re outside this radius, call anyway - we travel for larger projects and will tell you honestly whether the trip makes sense for your scope.
Serving Seguin, TX - Our Local Coverage Area

We’re based in the Seguin 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 - Attic Air Sealing in Seguin
Attic air sealing is the process of closing gaps, cracks, and penetrations in your attic floor and thermal envelope to stop uncontrolled air movement; insulation slows heat transfer but cannot stop air from flowing through it. In Seguin’s climate, a well-insulated but unsealed attic still loses 30-50% of conditioned air through leaks, which is why we seal first, then insulate - never the reverse. Call (830) 549-6646 and we’ll show you exactly where your home is leaking during a free estimate.
Most residential attic air sealing jobs in Seguin are completed in one day, with larger or more complex homes occasionally requiring a second day. We schedule arrival windows, text you when the technician is en route, and leave your home clean with a Documented Photo Record and written results before we go. Call (830) 549-6646 for availability - we can usually schedule within 24-48 hours.
Attic air sealing in Seguin typically ranges from $1,200 for focused repairs to $3,800 for complete sealing in larger or more complex homes, with most homeowners falling in the $1,800-$2,800 range. The exact price depends on attic size, accessibility, number of fixtures and penetrations, and whether existing insulation needs removal. We provide a flat, written price before any work starts - call (830) 549-6646 for your free estimate.
Yes, we source materials from Owens Corning, Icynene, and other major manufacturers including Demilec, GreenFiber, Johns Manville, Knauf, Rockwool, and CertainTeed - no proprietary product lock-in that limits your options. Our technicians are trained in the specific application requirements of each system, and we select materials based on your home’s needs and your written scope, not on distributor incentives. Call (830) 549-6646 to discuss which approach fits your project.
We answer calls with a live person 24/7 and prioritize same-day response for situations where attic air leaks are causing active HVAC failure, extreme temperature imbalance, or indoor air quality concerns from attic contamination. True emergencies in air sealing are rare, but when your home is unlivable due to envelope failure, we treat it seriously. Call (830) 549-6646 anytime - if we can’t get there today, we’ll tell you exactly when we can and what temporary measures help.
All attic air sealing is covered by our 365-Day Done Right Promise - if it’s not done right, we make it right - plus the written warranty delivered before work begins under Haven Standard Clause 1. The warranty covers materials and workmanship; if your blower-door numbers degrade or sealed areas fail within the warranty period, we return and repair at no charge. This is documented in writing, not implied.
Clear a path to your attic hatch and remove any stored items within 3 feet of the access point; we need workspace and safe ladder placement. If you have recent utility bills, have them available - they help us correlate your energy use with our blower-door findings. Pets should be secured away from work areas, and we’ll need access to all rooms for the blower-door test. We’ll text you when the technician is on the way, and you’ll receive your written price before any work starts.
Schedule Your Attic Air Sealing Service in Seguin Today

Call (830) 549-6646 now - a live person answers 24/7, and we’ll get you a written price before any work starts, guaranteed under Haven Standard. Your free estimate includes blower-door testing, thermal imaging, and a flat quote valid for 30 days. Whether you’re in Seguin proper, New Braunfels, Cibolo, or anywhere in Guadalupe County, we document every result so you know what you paid for.
Written by Wes Okafor, Owner at Topside Attic Insulation Seguin, serving Seguin, New Braunfels, Cibolo, and surrounding communities since 2016.