Crawl space vapor barrier in Gilroy CA - ground covered, problems fixed first
Bare dirt or torn old plastic under your house? We fix what's wrong first, then lay a liner that fits how you use the space.
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Does my crawl space need a vapor barrier?
A crawl space vapor barrier in Gilroy is a plastic ground cover laid over the dirt under your house, and a well-installed one helps keep ground moisture and soil gases from rising into the space and the floors above it.
Most folks call me after they've bought an older place and found bare dirt, a torn sheet of old plastic or a musty smell coming up through cold floors, sometimes alongside thin or missing crawl space insulation. The price mostly turns on how big the space is, how heavy a liner you pick, whether it stays on the ground or runs up the walls, and whether any water or mold has to be handled first. That last part drives the schedule too, because nothing goes down until the space is ready, and you'll get your own figure from the estimate visit.
How we put in a crawl space vapor barrier
First, I go down and look for standing water and mold, because plastic laid over either one just hides the problem, so we get those handled before anything else. Second, we talk about how heavy a liner makes sense, which mostly comes down to how often anyone goes down there, since a sheet that gets crawled on by a plumber or cable installer wears out a lot faster than one nobody touches. Third, our installers clear the debris, lay the liner over the whole floor with the seams overlapped and run it as far up the walls and piers as the plan calls for, and the work is backed by our satisfaction guarantee.
A crawl space job often connects to other work in the house. If you want a moisture barrier in walls or other parts of the house, that's our vapor barrier installation service. And since air from under the house tends to rise and slip out the top, plenty of homeowners pair this with attic air sealing, which closes the gaps around pipes, wires and the hatch before any insulation goes on top.
What to know about a crawl space vapor barrier in Gilroy
In California, someone without a contractor's license can only take a small job when the whole thing comes in under $1,000 and they don't hire anyone to help, a cap the state licensing board raised from $500. A full crawl space liner is usually more than one person handles alone, so it's worth asking whoever you hire to show you their license before anyone goes under your house.
Around here we go under a lot of older houses with raised floors, and plenty of them have boxes, scrap lumber or old plastic stored down there, so we ask you to clear out what you've stored so the new liner can cover the ground completely. We see the same setup on jobs in Morgan Hill and Hollister.
- Call (669) 205-6284
- Mon–Fri: 6 AM–11 PM, Sat–Sun: 7 AM–11 PM
- Gilroy, CA 95020
What happens after you call about your crawl space
Call or send the form
You call (669) 205-6284 or send the form, and I answer or get back to you. I'll ask whether you've seen standing water or mold and how often anyone goes down there, so I know what to look for.
I look under the house
I come out, go down into the crawl space and note anything that needs fixing before a liner goes in. Then I walk you through a written plan covering the liner weight, how far it runs and what comes first.
Installers work in order
Our installers follow the plan step by step, so any repair items are done before the plastic goes down. I check in along the way so you know what's happening next.
We go over the job
Before we pack up, I walk you through the finished crawl space. You'll know what's down there and where the liner runs.
Why Gilroy homeowners call Thermal Gilroy Spray Foam Insulation for crawl space work
The owner looks and plans
I've run this business since 2021, and I'm the one who comes out, goes under your house and writes the estimate. Our installers do the work while I check in, so you're never explaining your crawl space to a stranger.
Licensed and insured for crawl spaces
We're licensed and insured, which matters on a job bigger than the state's small-work cap allows an unlicensed person to take. It's the first thing worth checking with anyone you hire for this.
Based in Gilroy, working nearby
We're based in Gilroy and work in the cities around it, north into Santa Clara County and south toward Hollister, Salinas and Watsonville. If your city isn't listed on our site, call and ask.
If you're not sure your crawl space is ready for a liner, that's what the visit is for. Request your estimate and tell me a little about what's down there.
Request an estimateGet a written plan for your crawl space liner
We reply within 1 business day, and then I come out for a free on-site look at your crawl space and walk you through a written plan. There's no pressure to book.
- Licensed and insured.
- Phone
- (669) 205-6284
- Location
- Gilroy, CA 95020
- Hours
- Mon–Fri: 6 AM–11 PM, Sat–Sun: 7 AM–11 PM
Questions about crawl space vapor barriers in Gilroy
How much does a crawl space vapor barrier cost in Gilroy?
There's no single price, because it comes down to the size of your crawl space, how heavy a liner you choose, whether it covers only the ground or runs up the walls, and whether water or mold has to be handled first. A heavier liner and full wall coverage cost more up front, but a thin sheet that tears can mean paying for the job twice. You'll get your own figure from the estimate visit.
What is the best thickness for a crawl space vapor barrier?
Federal weatherization guidance sets 6 mil, a measure of sheet thickness, as the minimum, and 12 mil or heavier makes more sense if anyone will ever crawl on it. One installation guide recommends that heavier liner for any space people go into, since the extra material costs little next to the labor of redoing the job. We'll match it to how often you or a plumber goes down there.
How long does a crawl space vapor barrier last?
A thin sheet may last only a few years, while a heavy reinforced liner can last decades, going by one cost guide's estimates. That guide puts contractor grade 6-mil plastic at 3 to 5 years and a 20-mil reinforced barrier at 25 years or more. How much foot traffic it gets down there makes a real difference too.
Should my crawl space stay vented or be sealed with a vapor barrier?
If the vents stay open, a ground cover that runs a short way up the walls usually fits, and if the space gets sealed, the barrier goes further, with its seams and pipe openings sealed too. Federal guidance only seals seams and openings in unvented crawl spaces, and one installation guide runs a full encapsulation up the walls to a few inches below the sill, the wood that sits on top of the foundation. On walls and piers, federal guidance fastens the liner where needed so it stays put over time.
Does a crawl space vapor barrier help with radon?
A well-installed vapor barrier helps hold down soil gases like radon coming up from the ground, but it won't tell you how much radon your house has. The California Geological Survey says the only way to know your home's radon level is to test the air, so a test is the place to start if radon worries you.
What should I ask a contractor before installing a crawl space vapor barrier?
Ask how the barrier will leave your crawl space's existing drainage working, because federal guidance says the barrier shouldn't get in its way. It's also fair to ask what liner weight they're planning and why. I'll walk you through both when I come out.
Other work that goes with this job
Vapor barrier installation
Moisture showing up somewhere besides the crawl space, like in a wall? We can put a barrier there too.
Attic air sealing
Closing the leaks at the top of the house keeps air from under the floor from being pulled up and out.
Tell us what's under your house
Call (669) 205-6284 or send the form with a note on any standing water, mold, stored items and how often anyone goes down there, so I come out ready for your crawl space.
Request an estimateCall (669) 205-6284