CertainTeed Vapor Barrier Installation: The Boerne Owner’s Guide
Most CertainTeed vapor barrier installations in Boerne run between $1,400 and $2,800 for a full crawl space or attic floor application, depending on square footage and whether we’re sealing over bare earth or replacing a failed existing barrier. We stock CertainTeed MemBrain and standard 6-mil poly sheeting on our trucks, and we can usually inspect and quote same-day. Homeowners typically notice the problem first as a musty smell that returns after cleaning, or they spot drooping, torn plastic during a routine HVAC filter change in a Boerne crawl space.
Which CertainTeed Models This Applies To
CertainTeed’s vapor barrier line centers on two products we install regularly in Boerne homes: MemBrain, the smart vapor retarder that changes permeance with relative humidity, and their standard 6-mil polyethylene sheeting used in crawl space encapsulation and sub-slab applications. MemBrain carries a printed lot number and permeance rating (1 perm dry, 10+ perm wet) on the roll edge; standard poly is marked with mil thickness and ASTM E1745 compliance.
The compatibility gotcha in Hill Country homes: CertainTeed MemBrain is Class I at low humidity and Class III at high humidity, which means it belongs on the warm-in-winter side of the assembly. In Boerne’s mixed-humidity climate, we see it installed backwards in about one in five homes we inspect, trapping moisture against floor joists instead of letting walls breathe. We verify orientation with a simple tape test before sealing seams.
We’re an independent service provider, not affiliated with CertainTeed. We also stock Reflectix radiant barrier when a job calls for combined moisture and thermal control.
Signs Your CertainTeed Vapor Barrier Installation Is Failing
- Condensation pooling on top of the barrier. This means the seal at perimeter walls or piers has failed, letting warm, moist Boerne air hit the cool poly surface. Standing water breeds mold and eventually rots sill plates.
- Tears or rodent damage along seams. CertainTeed’s 6-mil poly is durable but not chew-proof. We find this most often near the Cibolo Creek watershed where crawl spaces stay damp enough to attract pests.
- Musty odors returning within days of cleaning. A functioning vapor barrier blocks soil gases and evaporated moisture; if the smell persists, the barrier has lost its seal or was never fully sealed at penetrations.
- Sagging or separated tape at seams. The acrylic tape used with MemBrain degrades in sustained high heat; Boerne attics hit 140°F in August, and we’ve seen tape failure in under three years in unventilated roof assemblies.
- Increased cooling bills with no equipment change. Moisture-laden air from a failed barrier raises effective cooling load. We measure this with a blower-door test - a pressurization reading that shows, in one number, how much conditioned air your building envelope is losing.
Replacement Cost & What’s Included
| Scope | Typical Range in Boerne |
|---|---|
| Partial repair (seam re-tape, localized replacement) | $650 - $1,200 |
| Full crawl space encapsulation, up to 1,500 sq ft | $1,400 - $2,200 |
| Full encapsulation, 1,500 - 3,000 sq ft | $2,200 - $2,800 |
| Attic floor vapor barrier with air sealing | $1,800 - $3,200 |
What drives the range: square footage, current barrier condition (removal adds labor), accessibility (Boerne’s older homes near Main Street often have 18-inch crawl spaces), and whether we find unsealed top plates or can lights that need addressing first. Every quote is a written price before any work starts - Haven Standard Clause 1. The installed work carries our 365-Day Done Right Promise, and you receive a Documented Photo Record plus before-and-after blower-door numbers on applicable jobs.
DIY or Call Us?
There’s a safe middle ground here. A homeowner can verify the problem: check for standing water, shine a flashlight on seam tape for separation, and note any musty smell. What you cannot safely assess is whether the barrier was oriented correctly for vapor drive direction, or whether the real leak is at the rim joist behind the barrier - a detail we catch with a blower-door and infrared camera.
Installing vapor barrier in a crawl space involves sharp fasteners, confined-space work, and proper overlap sequencing (12 inches minimum, taped, sealed to walls). Getting it wrong traps moisture and voids material warranties. We seal the envelope first. Then fill it. If you’re unsure, call (830) 529-7780 - estimates are free, and we bring the diagnostic tools to show you exactly what’s failing before quoting.
FAQs
In Boerne’s climate, properly installed 6-mil poly lasts 10 to 15 years in a ventilated crawl space; MemBrain can exceed 20 years if installed with correct orientation and sealed seams. Heat and rodent activity are the main limiters here, not the material itself. Call (830) 529-7780 and we’ll inspect yours at no charge.
Small punctures or tears under six inches can be patched with compatible tape and an overlay patch; anything larger, or damage near seams, means the seal is compromised and replacement is the sound fix. We don’t quote patches that won’t hold - it’s a waste of your money and our reputation. Bring us a competing quote; we offer a Free Second Opinion on any written estimate.
Most Boerne crawl spaces take one day for removal and replacement, or a half-day for new install in a clean space. Attic floor work runs longer if we’re air-sealing top plates and can lights first, which we do before any barrier goes down. You’ll get a written scope with the hour estimate before anyone lifts a tool.
Yes - we carry rolls of CertainTeed 6-mil poly and MemBrain, plus acrylic seam tape and mechanical fasteners for masonry and wood substrates. For Boerne jobs, we also stock Reflectix radiant barrier when a combined thermal and moisture solution makes sense. Same-day installation is available for most standard sizes.
Written by Wes Okafor, Owner, Topside Attic Insulation Boerne at Topside Attic Insulation Boerne, serving Boerne and nearby areas.