A crawl space vapor barrier is a heavy plastic liner that covers the dirt floor so moisture from the soil can't evaporate into the air under your home. Cobb installs 16 mil and 20 mil reinforced liners across Anderson and the Upstate. A barrier alone helps; a barrier plus sealed vents and a dehumidifier (full encapsulation) solves the problem.
Why the soil matters here
Bare crawl space soil gives off water vapor all day. Upstate red clay holds water long after a storm, so a bare floor keeps feeding moisture into the crawl space even in a dry week. Many older homes have a thin 6 mil sheet that has torn, shifted or been pulled up by service techs. That sheet does very little.
How we install a vapor barrier
- Debris and anything sharp is cleared from the floor.
- The liner is laid over the entire floor and run up the foundation walls.
- Seams are overlapped and taped so water vapor can't slip through.
- Piers are wrapped and the liner is fastened along the walls.
- Gold and Sapphire packages add a felt underlayment under a 20 mil liner for puncture resistance.
16 mil vs. 20 mil
Thicker liners resist punctures from knees, tools and future service calls. Our Silver package uses a 16 mil liner with a 10-year warranty. Gold and Sapphire use 20 mil with felt underlayment and a 30-year warranty. A 6 mil "contractor sheet" is not something we install as a permanent barrier.
Vapor barrier or full encapsulation?
If your vents are open, a vapor barrier alone won't stop humid summer air from coming in. That's why every Cobb package seals the vents and includes a dehumidifier. Read encapsulation vs. vapor barrier for the full comparison.
Where we work
We serve homeowners within about an hour of our Anderson shop, including Anderson, Greenville, Clemson, Easley, Seneca, Pickens, Powdersville, Greenwood and nearby towns in South Carolina and Northeast Georgia.