CertainTeed Vapor Barrier Installation: The Schertz Owner’s Guide
Most CertainTeed vapor barrier installations in Schertz run between $1,200 and $2,800 for a full crawl space or attic application, depending on square footage and whether the space needs prep work first. We stock CertainTeed MemBrain and standard 6-mil poly on our trucks, and we can usually schedule installation within 24 to 48 hours. Homeowners typically notice the problem first through musty odors in spring, cupping hardwood floors, or a sudden spike in cooling bills after a humid Schertz summer - all signs that moisture is moving through the envelope unchecked.
Which CertainTeed Models This Applies To
CertainTeed’s vapor barrier line centers on two products we install regularly in Schertz: MemBrain, a smart vapor retarder that changes permeability with humidity levels, and their standard 6-mil polyethylene sheeting for crawl space encapsulation. MemBrain carries a variable permeance rating of 1.0 to 10.0 perms - it tightens in dry winter conditions and opens up in summer when walls need to dry out. That’s particularly useful in the Schertz climate where we see 70% summer humidity drop to 30% in January.
To identify what you have now, look for the CertainTeed logo and product code printed in the seam margin. MemBrain sheets are marked “CT-MB-48” or similar; standard poly shows mil thickness and ASTM E1745 compliance. If your existing barrier is torn, stained, or pulled away from the walls, the printed edge is often the last readable section left.
We source CertainTeed materials through our standard supply chain alongside Owens Corning, Johns Manville, and Knauf - no proprietary lock-in, and we’ll tell you when a different spec makes more sense for your assembly. Aftermarket poly exists, but for crawl spaces with soil contact we prefer OEM-grade 6-mil minimum because thinner material degrades faster in the alkaline soils common east of I-35 in Schertz.
Signs Your CertainTeed Vapor Barrier Installation Is Failing
- Musty odors rising from floor level. When the vapor barrier separates at seams or pulls from foundation walls, soil moisture evaporates directly into the crawl space air. That humid air rises through floor penetrations and carries the smell of damp earth with it. In Schertz, we see this most often in homes built between 2005 and 2015 where original poly was stapled without mechanical fastening.
- Cupping or crowning of hardwood floors. Wood absorbs moisture from below, expanding across the grain and lifting at the edges. The vapor barrier’s job is to block that moisture path; once compromised, floor damage follows within a single humid season. We’ve documented this in Sedona subdivision homes where summer attic temps hit 140°F and crawl spaces mirror that heat with added humidity.
- Condensation on ductwork or insulation. When warm, moist crawl space air contacts cool HVAC ducts or fiberglass batts, water beads on the surface. This accelerates metal corrosion and compresses insulation R-value. CertainTeed MemBrain is designed to prevent exactly this cycle by maintaining proper permeance in both directions.
- Visible mold on floor joists or sill plates. Surface mold needs 60% relative humidity to colonize; a failed barrier lets crawl space RH climb well past that mark. We find this most often in north-facing crawl spaces in Schertz where shade keeps soil damp and airflow is minimal.
- Increasing cooling load with no equipment change. Humid air carries more latent heat; your AC works harder to dehumidify before it can cool. A blower-door test - a pressurization reading that shows, in one number, how much air your building envelope is losing - often reveals crawl space bypasses contributing 15% to 25% of total air leakage.
Replacement Cost & What’s Included
| Scope | Price Range in Schertz |
|---|---|
| Standard crawl space, up to 1,000 sq ft (6-mil poly, taped seams, mechanical fastening to walls) | $1,200 - $1,800 |
| Same with MemBrain smart retarder | $1,600 - $2,200 |
| Full encapsulation with closed-cell spray foam rim joists | $2,200 - $2,800+ |
| Attic vapor retarder installation (MemBrain under roof deck) | $1,800 - $2,600 |
What drives the range: accessibility (crawl height and debris), whether existing material needs removal, and the condition of the rim joist area. We don’t quote by phone without seeing the space - but we do provide a written price before any work starts, always, under Haven Standard Clause 1. That written scope includes material spec, seam-taping method, wall-attachment detail, and our 365-Day Done Right Promise. Every job closes with a Documented Photo Record showing before condition, installed barrier, and fastener spacing.
DIY or Call Us?
There’s a clear line between what you can check and what we handle. You can safely verify: whether your existing barrier is still attached to walls, whether seams are taped or gaping, and whether there’s standing water that needs drainage first. Use a flashlight and a moisture meter from any hardware store - readings above 20% in wood mean active moisture movement.
Where DIY goes wrong: crawl spaces are confined spaces with real hazards. Soil gases, electrical runs, and structural instability aren’t visible from the hatch. More importantly, vapor barrier effectiveness depends on continuity - one untaped seam or unsealed penetration undoes the entire installation. We’ve been called to Schertz homes where a homeowner’s weekend project left gaps at piers and plumbing stacks, and the moisture problem returned within months. Seal the leaks first. Then insulate. The attic doesn’t care how thick the insulation is if the air is still moving through it.
We carry CertainTeed-compatible materials on our trucks, and we sequence the work correctly: blower-door test to find air leaks, air sealing of top plates and penetrations, then barrier installation. Call (830) 402-5240 for a free estimate - we’ll read any written quote you’ve already received and give you a free second opinion.
FAQs
In the Schertz climate, properly installed 6-mil poly lasts 15 to 20 years; MemBrain’s active polymer layer maintains performance for 20-plus. Lifespan shortens significantly if the original installation skipped mechanical fastening to walls or used inadequate tape at seams - we see premature failure in 8 to 10 years when those details are missed. Call (830) 402-5240 and we’ll inspect what you have now.
Small punctures or tears under six inches can be patched with compatible tape and an overlaid scrap piece. Wides seam separation, wall detachment, or brittle material that tears when handled means full replacement is the only fix that performs. We document the condition with photos during our inspection so you can see what we see. Estimates are free - call (830) 402-5240.
A standard crawl space vapor barrier installation takes one day for a two-person crew; full encapsulation with rim joist sealing takes two days. We arrive with materials on the truck, so there’s no supply delay. Under Haven Standard, you get a named technician and a text when they’re on the way.
Yes - we carry CertainTeed 6-mil poly and MemBrain in standard 4-foot and 8-foot widths, plus compatible tapes and mechanical fasteners. We’re an independent service provider, not affiliated with CertainTeed, but we stock their materials because the specs hold up in our local conditions. If your job calls for a different brand, we also stock Reflectix and can source Johns Manville or Owens Corning without delay.
Written by Wes Okafor, Owner, Topside Attic Insulation Schertz at Topside Attic Insulation Schertz, serving Schertz and nearby areas.