Not a builder-grade 6-mil sheet held down with rocks. A real 20-mil reinforced polyethylene liner, mechanically fastened, taped at every seam, wrapped up walls and around piers. This is the moisture barrier that lasts 20+ years.
A licensed local crew — usually out in 24 to 72 hours. Written scope, fixed price, no pressure.
Vapor barrier calls in Stallings are almost always somebody who read a home inspection report at closing and wants to know why the inspector wrote up the crawl for having deteriorated vapor barrier. Answer is always the same: it is the original 6-mil clear plastic the builder rolled out over the graded dirt in 1997 or 2002 or 2006, no seam tape, no pier wrap, torn along every seam, bunched up around every pier, and covered in twenty years of pest droppings, dust, and settled moisture. That is not a vapor barrier anymore. That is a decoration.
Two weeks ago I dropped in under a 1998 Ashe Plantation colonial off Idlewild Rd. Owner had just bought the house and the inspection report flagged 'vapor barrier deteriorated, recommend replacement.' Under the house I found exactly what I expected — original 6-mil clear plastic torn into rags, half of it missing entirely along the north wall where it looked like a raccoon had had a rough winter under there at some point in the past. The remaining sheets were bunched up around 14 of the 22 piers, seams were never taped in the first place, and there was no wall extension at all. Just plastic on the ground where it happened to fall. Hygrometer read 79 percent RH at 10 in the morning. Fiberglass batts in the rim were mostly gone or hanging out. Standard late-90s Emerald Lake and Ashe Plantation setup.
Now — vapor barrier by itself, meaning just replacing the ground plane with better material, is a legitimate scope on some houses. Not every crawl needs full encapsulation. But in Union County with our summer dew points and the way vented crawls behave from May through October, a standalone vapor barrier install without sealing the vents and adding a dehumidifier is a partial solution. It will slow moisture migration from the ground into the crawl, which helps. It will not stop the outdoor humid air flowing through the open vents and condensing on cold surfaces, which is where 70 percent of the moisture load actually comes from. So when a homeowner asks for just a vapor barrier install, I give them the honest picture and let them decide the scope.
What follows is what a real vapor barrier install looks like on a Stallings house, what it does and does not do, and when it is the right call versus when you should be looking at full encapsulation. Free on-site inspection with a moisture map and a hygrometer read. No prices in here — those come after the inspection.
Every Stallings vapor barrier install starts with the same three questions I would ask on an encapsulation job: what is the exterior grading, what is the current moisture load, and what is the homeowner's actual goal. The install itself is a subset of encapsulation — just the ground plane and pier wraps, without necessarily the wall extension, vent sealing, or dehumidifier. So the diagnostic upfront determines whether standalone vapor barrier is going to solve the problem or whether the homeowner needs to know they are buying a partial fix.
Exterior walk first, five minutes around the perimeter. If the lot is pushing water at the foundation — pooling against block after summer thunderstorms, efflorescence on the exterior side of the block, downspouts dumping close — a ground-plane vapor barrier alone is not going to hold up. Water will keep wicking through the CMU into the crawl, RH will keep running high, and the vapor barrier is functioning as a nonexistent exterior wall against water intrusion. On those houses I tell the homeowner: either fix the drainage first and then install the vapor barrier, or move to a full encapsulation scope with wall termination and dehumidifier so we are actually controlling the moisture. Standalone barrier on a wet lot is not a scope I recommend.
If the lot is graded fine — which on older Ashe Plantation streets and parts of Emerald Lake is often the case — standalone vapor barrier install can be the right first-step scope, especially for a homeowner who wants to address the inspection report before resale without committing to a full encapsulation budget. Install sequence in that case: day one is tear-out. Old 6-mil comes up in strips, gets bagged. Any severely wet or deteriorated fiberglass in the rim gets pulled and noted for future replacement, but we do not necessarily replace it as part of the vapor barrier scope. Any standing water gets pumped out and the ground gets time to surface-dry.
Day two is the barrier install. 20-mil reinforced woven poly — YellowGuard, Viper CS, or Americover depending on availability — rolls down over the graded dirt with 12-inch seam overlaps top-taped with Polyken 337 or Nashua 357 double-sided PSA. Every pier gets individually wrapped and taped. On an Emerald Lake or Ashe Plantation crawl running 20 to 25 piers that is a couple hours of pier wrap work by itself. Sometimes we extend the barrier partially up the block wall — 8 to 12 inches with mechanical termination — as an intermediate step that stops short of full encapsulation but gets the perimeter protected. On a standalone vapor barrier scope without dehumidifier or vent sealing, wall extension is optional and I discuss it with the homeowner based on what they want to accomplish.
What I do not do on a standalone vapor barrier scope is pretend it is a full encapsulation. If the vents are still open at the end of the job, if there is no dehumidifier, if the wall liner is not fully terminated — the crawl will still run in the 65 to 75 percent RH range through summer. That is better than the 80-plus percent it was running before the barrier went down, because ground moisture migration is significantly reduced. But it is not the 55 percent RH you get with full encapsulation. Homeowner needs to know that going in. If they want the 55 percent number, they need the full scope. If they want to slow ground moisture and satisfy an inspection report finding, standalone barrier does that.
Ground plane material is 20-mil reinforced woven poly, same as we use on full encapsulation. YellowGuard, Viper CS, or Americover — all three are woven scrim laminated between poly layers and will not tear under work-boot traffic. Not 12-mil, not 10-mil, definitely not the 6-mil builder plastic we tear out. The material cost difference between 20-mil and 12-mil on a typical Stallings crawl is not enough to compromise the install, and 20-mil holds the seam tape better long-term because the scrim gives the adhesive something to grip.
Seam tape is Polyken 337 or Nashua 357 double-sided PSA seam tape, top-taped over 12-inch minimum seam overlaps. Butyl tape does not go on an unconditioned Stallings crawl — it creeps in the summer heat and seams walk apart by August. Double-sided PSA holds through the temperature swings.
Pier wrap is individual, taped, and terminated at pier top with a bead of SikaFlex-1a to prevent moisture wicking from the pier concrete into the framing above. Skirted piers where the sheet just runs around the pier without wrapping — that is the shortcut we tear out on failed builder partial encaps in Chestnut and Idlewild. Pier concrete wicks ground moisture right up behind the barrier and you end up with condensation trapped between plastic and concrete on the framing side.
Optional wall extension is 12-inch minimum up the block, mechanical termination bar of 1-inch by 1/8-inch aluminum stock fastened with 2-1/4-inch Tapcon masonry screws every 12 inches on center, bedded in SikaFlex-1a. Same specs as full encapsulation wall termination. On a standalone vapor barrier scope without dehumidifier, wall extension is an intermediate step that stops short of full encapsulation but gets the block perimeter protected against wicking moisture. Homeowner choice based on scope preference.
What is not included in a standalone vapor barrier scope: vent sealing, dehumidifier, rim insulation replacement, block wall crack injection, exterior drainage work. Any of those can be added to the scope on request or handled as a separate future phase. But without them, the vapor barrier is doing about 60 percent of what full encapsulation does, and homeowner needs to know that number going in so expectations match reality.
Yes — Stallings is a regular vapor barrier route. Free on-site inspection anywhere in Stallings, fixed written quote before we touch anything.
Vapor barrier as a standalone scope in Stallings is a legitimate first-step solution on graded lots along Ashe Plantation and older Emerald Lake streets, but on the flat Old Monroe Rd corridor where drainage is a bigger driver, a ground-plane vapor barrier alone will underperform unless the exterior water source is addressed and the vents are sealed at the same time.
28104, 28079. All Union County addresses covered.
Depends on your goal. If you want to reduce ground moisture migration into the crawl, satisfy a home inspection report finding, and address maybe 60 percent of the total moisture problem for a portion of the full encapsulation cost, standalone vapor barrier is a legitimate scope on a graded Stallings lot. If you want the crawl to run at 55 percent RH through August and eliminate the wet-dog smell in the house, that requires vent sealing and a dehumidifier on top of the barrier — full encapsulation. The barrier by itself will not get you the 55 percent number. Free on-site inspection, we walk through the tradeoffs, you decide which scope fits your goal and budget.
It means the original 6-mil clear plastic the builder rolled out over the dirt is torn, bunched, and no longer functioning as a moisture barrier. In an Emerald Lake, Ashe Plantation, or Chestnut crawl that plastic is 15 to 30 years old, was never seam-taped or pier-wrapped, and has been walked on by HVAC techs, pest control guys, and the previous owner's teenager who thought the crawl was a good storage spot. It is not a repairable finding — it needs to be torn out and replaced. Whether you replace with just a vapor barrier or go straight to full encapsulation is the scope conversation.
You can, and some homeowners do. Two things to know first. One: 20-mil reinforced poly is heavy and awkward to work with in a 38-inch clearance crawl on your back — I am under houses six days a week and I am tired at the end of the day. Two: the seam tape, pier wrap, and wall termination specs matter, and the failure mode of a DIY install is usually not the sheet itself but the seams walking apart or the piers skirted instead of wrapped. If you want to DIY, buy the 20-mil not the 12-mil, use double-sided PSA seam tape not butyl, and individually wrap every pier. If you skip any of those the install fails inside three summers. Or hire it out and get warranty on the workmanship.
20 to 25 years on the material if it is 20-mil reinforced woven poly, seams top-taped with double-sided PSA, and piers individually wrapped. The failures we see at year three to five are always the shortcut installs — 12-mil material, skirted piers, wall termination with tape stuck to dusty block instead of mechanical bar. Do the specs right and the barrier outlasts most of the mechanical systems in the house. Add vent seal and a dehumidifier on top of it for full encapsulation and you get the same 20 to 25 year barrier life plus 8 to 12 years on the dehumidifier as a consumable, and the crawl runs at 55 percent RH through the summer instead of the mid-60s.
Free on-site Stallings inspection. Fixed written quote. Call (980) 227-1769 or book below.