Demilec Wall Insulation in Seguin: What to Know First
We provide independent Demilec wall insulation service in Seguin, typically scheduling within 48 hours and completing most jobs in a single day. Most Demilec injection foam and drill-and-fill wall jobs in Seguin run between $2,800 and $5,400 depending on wall cavity depth, square footage, and whether we’re working around existing Demilec foam that’s degraded or failed to cure properly. We don’t start any job without a written price and a written scope - that’s Haven Standard Clause 1, and it’s how we’ve operated since 2016.
This page is for Seguin homeowners who have Demilec foam in their walls and are dealing with settling, shrinkage, moisture issues, or simply need exterior walls topped off after a renovation. If you’re in an older home near the Guadalupe River corridor or in one of the 2015-2020 builds around Kingsbury where Demilec Heatlok HFO was commonly spec’d, you’re who we’re talking to. Call (830) 549-6646 to schedule a free estimate, or bring us a competing written quote for a free second opinion.
How Demilec Products Fail - and How We Fix Them
- Heatlok HFO shrinkage in 2×4 exterior walls. The HFO blowing agent in this series can produce foam that shrinks 3-8% during cure in Seguin’s combination of high summer humidity and rapid temperature swings. We’ve pulled Heatlok HFO from walls in the River Plantation area that had pulled away from studs by a half-inch, creating convective loops that move heat straight past the cavity. We remove the failed foam with mechanical extraction, verify the wall sheathing is dry with a moisture meter, then reinstall using a corrected mix ratio and density check every 100 board feet.
- Heatlok XT moisture retention in south-facing gable walls. The higher closed-cell density of XT (2.0-2.2 lbs/ft³) performs well until it’s installed over damp OSB during Seguin’s spring build season. In homes near Seguin High School built in 2017-2019, we’ve found XT that trapped construction moisture against the sheathing for years, leading to fungal growth on the back side of the drywall. We don’t cover that up - we open the cavity, treat the substrate, and reinstall only after a 48-hour moisture-content verification.
- Sealection 500 open-cell sag in cathedralized ceilings carried into wall headers. Sealection 500 is an open-cell product at 0.5 lbs/ft³, and when installers overfill wall headers or chase cavities without proper venting, gravity wins in Seguin’s heat. We’ve found 4-inch sag pockets in header assemblies above patio doors in homes off Highway 46. The fix is complete removal, installation of proper air barriers at the header, and reapplication with density monitoring to prevent overfilling.
- Demilec APX adhesive failures at the stud interface. APX, the two-component adhesive used to bond Demilec foam to framing, can delaminate when applied over kiln-dried lumber with moisture content below 12% - common in Seguin’s driest months. The foam looks fine from the interior but isn’t attached to anything. We test adhesion with a pull sample before committing to a repair plan, and when we reinstall, we specify substrate conditioning and a different primer schedule.
- Re-Entry foam degradation from UV exposure through wall penetrations. Demilec’s Re-Entry product line, used for retrofit drill-and-fill applications, degrades when repeated UV hits it through unsealed electrical box cutouts or plumbing vent penetrations. In Seguin’s 300+ days of annual sunshine, that’s not theoretical. We seal every penetration with fire-rated caulk before foam installation, and we document each one with a photo that goes in your job record.
Our Demilec Wall Insulation Process
- 1
Call and scope. A live person answers - no voicemail loop. We schedule an in-home assessment, usually within 48 hours. You get a text with your technician’s name when they’re en route.
- 2
Blower-door test and infrared scan. We run a blower-door test - a pressurization diagnostic that measures how much conditioned air your home loses per hour - to establish a baseline. Then we use thermal imaging to locate exactly where Demilec foam has failed, settled, or was never properly installed. The report goes home with you - the numbers do the talking.
- 3
Written price before any work starts. We specify OEM Demilec material versus quality aftermarket alternatives where appropriate, explain the trade-off, and give you a flat price. No work starts without your signature on a written scope and warranty.
- 4
Air sealing first, then insulation. We seal top plates, electrical penetrations, and box headers before any foam goes in. Blowing insulation over an unsealed envelope is something we simply don’t do.
- 5
Installation with density verification. For closed-cell jobs, we pull a core sample every 100 board feet to verify density. For open-cell, we check thickness at multiple points. Everything is photographed.
- 6
Post-test, documentation, and cleanup. We run a second blower-door test and hand you a printed report with your pre- and post-installation ACH50 numbers. Your Documented Photo Record is uploaded same day. The 365-Day Done Right Promise begins immediately.
Before
AfterWhat Demilec Wall Insulation Costs in Seguin
These are real ranges from jobs we’ve completed in Seguin and the Hill Country edge, not teaser rates:
| Job Type | Typical Range | What Moves the Price |
|---|---|---|
| Drill-and-fill retrofit, 1,200 sq ft home | $2,800 - $4,200 | Stucco vs. siding exterior, cavity obstructions, number of stories |
| Heatlok HFO removal and replacement, 2×4 walls | $4,100 - $5,800 | Extent of shrinkage, moisture damage to sheathing, accessibility |
| Open-cell top-off after partial settling | $1,900 - $3,400 | Cavity depth, whether original foam can stay or must be removed |
| Interior wall soundproofing with Demilec | $3,200 - $5,400 | Number of walls, electrical rerouting, STC rating target |
Two-story homes in the Oaks of Seguin or similar developments with complex roof-wall junctions tend toward the higher end. Single-story ranch homes near Guadalupe Regional Medical Center with straightforward stud bays usually land lower. We don’t do “starting at” pricing - the number we write is the number you pay. Call (830) 549-6646 for a free estimate with no pressure to decide on the spot.
Why Seguin Homeowners Call Topside Attic Insulation Seguin for Demilec Work
We’ve sealed and insulated over 9,000 homes since 2016, and a growing share of our Seguin work involves fixing or completing Demilec installations that didn’t perform as expected. Wes Okafor, our owner and lead technician, learned thermal envelope science at Triton College in River Grove, IL - coursework most installers never get - and he’s run blower-door tests on Demilec jobs from the original Heatlok series through current HFO formulations. We also work with Reflectix and other brands, so if your walls need a hybrid approach or Demilec isn’t the right product for your specific assembly, we’ll tell you straight.
Every job gets the same documentation: written price, written scope, written warranty, printed blower-door report, and a photo record you can access. Our 365-Day Done Right Promise means if it’s not right, we make it right. Calls are answered by a live person 24/7. Background-checked, uniformed technicians. No exceptions.
FAQs
Demilec’s material warranty covers manufacturing defects, not installation errors, and it remains valid regardless of who services the product - what voids coverage is using non-Demilec material in a way that damages the original foam, or failing to follow published installation parameters. As an independent Demilec service provider, we document every step to manufacturer spec and flag when a job falls outside warranty parameters before we start. Call (830) 549-6646 and we’ll review your specific situation.
We source OEM Demilec resin and catalyst for jobs where matching the original formulation matters, particularly for Heatlok XT repairs where density must interface with existing foam. For full removals and replacements, we sometimes recommend quality aftermarket alternatives with equivalent R-value and vapor permeance ratings - we explain the trade-off in writing and let you decide. No proprietary lock-in.
Localized shrinkage or adhesion failures in accessible walls can often be spot-repaired for $1,200-$2,500, but if the failure pattern is systemic - multiple walls, multiple floors, or moisture-compromised sheathing - full removal and replacement is usually more cost-effective over a 15-year horizon. We assess both options during your free estimate and give you written pricing for each. Call (830) 549-6646 to schedule.
Most drill-and-fill retrofits and repair jobs are completed in one day; full removals with sheathing repair typically take two days. We schedule within 48 hours of your call, and we don’t book more work than we can finish on time - Haven Standard: Arrive on schedule, with a named technician and a text when they’re on the way.
You receive a printed blower-door report with pre- and post-installation CFM50 and ACH50 numbers, a written scope describing exactly what was done, a written warranty under our 365-Day Done Right Promise, and access to a digital photo record of your job. We don’t make you ask for it - it’s part of the job, every time.
Written by Wes Okafor, Owner & Lead Insulation Technician, Topside Attic Insulation Seguin at Topside Attic Insulation Seguin, serving Seguin and nearby areas.