CertainTeed Crawl Space Encapsulation Nationwide

CertainTeed Crawl Space Encapsulation: The San Marcos Owner’s Guide

We stock and install CertainTeed-compatible crawl space encapsulation systems in San Marcos, with most full encapsulations running between $3,800 and $7,200 depending on crawl space square footage and existing moisture damage. Same-day assessments are available, and we carry CertainTeed vapor barrier rolls, seam tape, and foundation vent seals on our trucks. Most homeowners realize their encapsulation has failed when they notice a sharp musty smell returning after months of absence, or when their dehumidifier in the crawl space runs continuously without reaching its set point - both signs that the vapor barrier has torn at seams or pulled away from the foundation walls, letting Gulf Coast humidity back underneath the home.

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Which CertainTeed Models This Applies To

CertainTeed’s crawl space product line centers on their MemBrain smart vapor retarder and the DryRight woven polyethylene barrier series, typically found in 6-mil, 10-mil, and 16-mil thicknesses. The MemBrain line is the variable-permeability option - it opens to let moisture escape when humidity is low and tightens when humidity rises - while DryRight is the standard woven poly used in most San Marcos encapsulations we encounter. To identify what you have, check the white printed stripe running every 24 inches along the roll edge; MemBrain will show “CertainTeed MemBrain” and a lot number, DryRight will show “CT DryRight” with the mil thickness.

The compatibility gotcha in this market: CertainTeed’s 2018-2021 DryRight rolls used a slightly narrower 13-foot width versus the current 16-foot standard. If your crawl space was encapsulated in that window, patching with off-the-shelf 16-foot material creates a 3-foot excess fold that traps condensation at the seam. We stock both widths. For OEM versus aftermarket, we source CertainTeed material through their distribution network for warranty-registered jobs, but we also carry Reflectix woven poly as a field-proven alternative when CertainTeed lead times stretch past two weeks. The Reflectix product matches the puncture resistance spec but runs slightly thinner at 12 mil versus CertainTeed’s 16 mil - we note this in writing before any substitution.

Signs Your CertainTeed Crawl Space Encapsulation Is Failing

• Musty odor returning upstairs. When the vapor barrier separates from sill plates or tears at pier supports, soil gas and evaporating ground moisture bypass the encapsulation. The stack effect in a San Marcos home - warm air rising through floor penetrations - pulls that damp air straight into living spaces above.
• Dehumidifier running nonstop or icing over. A properly sealed crawl space should hold 50-55% relative humidity with normal dehumidifier cycling. If your unit never reaches set point, the encapsulated volume has effectively doubled through barrier breaches, overwhelming the equipment sized for the original sealed footprint.
• Soft or cupping hardwood floors. Moisture migrating through compromised barrier sections raises the wood equilibrium moisture content from a stable 6-8% to 12% or higher. In San Marcos, we see this most often in 1970s-1990s slab-adjacent homes near the Blanco River corridor where seasonal groundwater shifts stress the barrier at perimeter walls.
• Visible condensation on ductwork or insulation. When humid outside air enters through gaps, it contacts the 55°F surface of air conditioning ducts in summer. The resulting drip pan fills, rusts metal fittings, and can saturate fiberglass batt insulation hung in the crawl space joist bays.
• White or gray mold spotting on the barrier surface. This is biological activity on trapped organic dust, not the barrier itself failing - but it signals that air movement is occurring where the seal should be absolute. The barrier has become a shelf for spores rather than a moisture block.

Before

After

Replacement Cost & What’s Included

Full CertainTeed encapsulation replacement in San Marcos typically falls between $3,800 and $7,200 installed. The low end covers a clean, rectangular crawl space under 1,000 square feet with straightforward pier spacing and no active mold remediation needed. The high end reflects larger footprints, extensive seam repair in tight clearance areas, replacement of degraded foundation vent seals, and re-anchoring of dehumidifier drain lines to code.

Every job includes removal and disposal of the existing barrier, surface prep including mold inhibitor application where spotting is present, installation of new CertainTeed or equivalent material with double-sided seam tape at all overlaps, mechanical fastening to sill plates with pressure-treated furring strips, and sealing of all perimeter penetrations. We run a blower-door test before and after - a pressurization reading that shows, in one number, how much air your building envelope is losing - and you receive the before-and-after CFM50 figure on a single printed page. The R-value tells you how slow heat moves through the material - the blower-door number tells you whether any of that matters. Work is covered by our 365-Day Done Right Promise, with the written scope and warranty delivered before any crew member enters the crawl space.

DIY or Call Us?

What you can safely check: verify your dehumidifier drain line isn’t simply clogged or dislodged, and inspect the barrier perimeter at foundation vents for obvious tears or tape failure. These are visual checks from the crawl space entry - no tools required.

Where DIY goes wrong: crawl space work involves confined-space entry, sharp foundation hardware, and fiberglass insulation contact that most homeowners underestimate. More critically, proper encapsulation requires negative-pressure verification - testing that the sealed space actually holds its boundary - which demands a blower door and manometer setup no rental center carries. We’ve been called to San Marcos homes where a homeowner’s patch job trapped moisture against sill plates, accelerating rot that a proper assessment would have caught. If your barrier is failing in multiple locations or your home predates 2000, the underlying air sealing at rim joists likely needs attention too. Call (737) 337-8049 for a free assessment - we bring the diagnostics, not just the material.

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