In Western North Carolina, our high humidity, heavy rains, and mountain terrain make crawlspaces especially vulnerable to moisture and mold issues. I regularly meet homeowners who invested thousands in encapsulation—only to discover critical steps were skipped.Before you sign a contract, use this checklist to make an informed, science-based decision.
✅Confirm There Is No Active Water Intrusion
Encapsulation is not a solution for bulk water problems. Check for:
• Standing water or damp soil
• Foundation seepage
• Poor exterior drainage
• Gutter discharge near foundation
• Hydrostatic pressure issuesIf water intrusion exists, it must be corrected before encapsulation. Installing a vapor barrier over a drainage problem can lead to:
• Trapped moisture
• Mold growth
• Structural damage
• Costly tear-outs later to install sump pumps or water management systems
Fix the water first. Encapsulate second.
✅ Verify Vapor Barrier Material Quality (And How It’s Installed)
Not all vapor barriers are created equal.
Instead of focusing only on thickness, focus on material quality and installation method.
It is best to use virgin polyethylene (not recycled material).
Why this matters:
• Recycled plastics can off-gas over time
• Some lower-grade recycled liners produce an odor often described as “cat urine”
• Virgin material is more chemically stable and less likely to create long-term odor issues
Also ask how the liner is attached to the walls. Avoid systems that rely heavily on glues and spray adhesives to secure the vapor barrier.
Some adhesives can off-gas and produce odors described as:
• Musty
• Chemical
• Similar to ammonia or cat urine
A properly installed system should use mechanical fastening methods combined with appropriate sealing techniques—not excessive adhesive that can create indoor air quality concerns later. Encapsulation is meant to improve your air quality — not introduce new odor issues.
✅ Ensure Proper Installation Height & Code Compliance
In many cases, I see vapor barriers installed: • Only partway up the wall
• Stopping halfway up block
• Installed just high enough to save material
That is not full encapsulation.
Proper installation should:
• Run up foundation walls per building code
• Be mechanically fastened and sealed
• Extend high enough to prevent moisture migration
• Terminate correctly (not randomly mid-block)
Half measures create half results — and ongoing humidity issues.
4. ✅ Confirm the System Is Actually Sealed
Encapsulation is about air control, not just plastic.
Ask:
• Are seams taped and sealed properly?
• Are wall penetrations sealed?
• Are piers wrapped and sealed?
• Are rim joists addressed?
If the wall vapor barrier isn’t properly sealed, humidity can migrate through block walls. This can create a vapor trap, increasing moisture levels inside the crawlspace instead of reducing them.
The science matters.
✅ Research the Dehumidifier Brand & Capacity
The dehumidifier is the engine of your encapsulated crawlspace. Do not accept off-brand or undersized units.
Look for:
• Crawlspace-rated equipment
• Proper capacity for square footage
• Reliable brand reputation
• Serviceability and warranty
One example of a trusted unit is the Aprilaire E080 (commonly referred to as the AprilAire 80). It’s known for durability and performance in crawlspace environments.
Top-line equipment protects your investment long-term.
✅ Test Mold & Wood Moisture Levels Before Encapsulation
Encapsulation does not kill active mold.
Before sealing the crawlspace, you should know:
• Are there elevated mold levels?
• Is there active mold growth on wood?
• What are the wood moisture readings?
Healthy wood moisture levels:
• Target average: 8–11%
• Maximum acceptable: Below 18%
If wood moisture is above 18%, mold risk increases significantly. If you encapsulate without addressing elevated moisture or active mold, you may trap a problem inside.Have a plan:
• If moisture is high, what is the remediation strategy?
• Will antimicrobial treatment or remediation be performed?
• Will moisture be rechecked post-install?
A Question Every Homeowner Should Ask
Crawlspace encapsulation in Western North Carolina typically ranges from $7,000 to $10,000 or more, depending on size and scope.
Before you move forward, ask yourself:
Can you afford to eat $7,000–$25,000 if you make a decision you later regret?
Choosing the wrong contractor, the wrong materials, or skipping critical steps can turn what should be a protective investment into a costly redo.
Final Thoughts: Make an Informed Decision
In Western North Carolina’s climate, crawlspace encapsulation can be one of the smartest investments you make in your home — but only if it’s done correctly.
Be sure:
• Water intrusion is corrected first
• High-quality virgin vapor barrier material is used
• Adhesive-heavy installation methods are avoided
• Installation follows building science principles
• Mold and moisture levels are understood beforehand
• Equipment is properly sized and reputable
A well-informed decision today can prevent thousands in remediation, structural repair, and tear-out costs later.