Bare dirt under the house
If you open the crawl space hatch and see nothing but dirt, ground moisture has a straight shot at your floor framing. That's the plainest case for a cover.
Vapor barrier installation in Modesto, CA - a drier crawl space under your floors
Musty smell or cold floors over the crawl space? We sort out the water first, then lay a cover that keeps ground moisture down.
- Licensed and insured.
- Free on-site estimates.
- We respond within 1 business day.
What a crawl space vapor barrier does for your house
Vapor barrier installation in Modesto means laying heavy plastic over the bare dirt in your crawl space, so moisture coming up from the ground stays out of your floor framing and the rooms above it.
You usually notice the problem upstairs first, as a musty smell, cold floors or rooms over the crawl space that never feel quite dry. This page covers crawl spaces only, since barriers under slabs and inside walls are different jobs. The price turns on how big your crawl space is, how hard it is to get into, whether old plastic or debris has to come out, whether the drainage outside needs fixing first, and whether you want a plain cover or a fully sealed crawl space. The schedule mostly depends on that drainage work and on a permit and inspection if your job needs one. I come out, look under the house and write the estimate, so the number fits your house and not a guess.
Modesto is home base, and we work in the cities around it in Stanislaus County and over into San Joaquin and Merced counties, so call and ask if you're not sure we come out your way.
I go over the finished job
Our installers do the work, and I go over the finished job with you at the end, so the person who wrote the estimate checks the work. We've been at this since 2013.
Gas appliances checked first
If a furnace or water heater burns gas under or near the crawl space, I check it before we make anything tighter, because a sealed space changes the air those appliances draw on.
Licensed and insured
We're licensed and insured. California's contractor board counts installing insulation as insulation contractor work, so if a sealed crawl space adds insulation, it's fair to ask anyone you hire about their license.
How we lay a crawl space vapor barrier
I start outside, which is the nicest part of a crawl space job. If rain ends up under the house, plastic on top just holds it there, so I look at how the ground slopes around the foundation and where the downspouts dump water before anyone crawls in with a roll of plastic. If water is heading toward the house, that gets sorted out first, and I'll tell you what it needs.
Then we go over the two options. With a plain ground cover, our crew clears out debris and old torn plastic, lays new plastic over the dirt, overlaps the seams and runs the edges up the foundation walls, and the vents stay open. A fully sealed crawl space is a much bigger job that adds insulation and air sealing on top of the cover. I'll usually point you to the plain cover first, since it goes after ground moisture for far less work, and save sealing for houses where it earns its keep.
If you do go the sealed route, it ties into the rest of the house. On an older home it often goes along with retrofit insulation in the walls or floors, and attic air sealing closes the gaps up top, so the house pulls less air up from under the floor.
Signs your crawl space needs a cover
Old plastic that's torn or shoved aside
Plastic put down years ago is often torn, buried in dirt or pushed aside by whoever last worked down there. Patches rarely hold, so we usually pull it out and start fresh.
Musty smell or clammy floors
A musty smell in the rooms over the crawl space, or floors that feel cold and clammy, often starts with the dirt below. A cover is usually the first fix worth trying.
Before insulating under the floor
If you're adding insulation under the floor, the ground cover goes in first. Insulation hung over damp dirt soaks up moisture, and then you're paying for the same job twice.
Set up your free crawl space estimate
Send the form and we'll get back to you within one business day to set a time. I'll come out, look under the house and write you a free estimate, with no obligation.
Both options laid out side by side
I'll walk you through a plain ground cover next to a fully sealed crawl space, so you can see what the bigger job buys you before you decide on anything.
Call any day until 11 PM
You can reach us Monday through Sunday from 7 AM to 11 PM, so a call after work or on a weekend still gets a time set for me to come look.
Tell us what you've seen
If you've noticed standing water, taken humidity readings or know whether the foundation has wall vents, put it in the form. It tells me where to start looking under your house.
Crawl space vapor barrier examples
These example photos show the kinds of ground covers, seam overlaps and sealed crawl space layouts we can go over with you at the estimate.
Questions about crawl space vapor barriers
Questions we hear about crawl space covers, sealing, cost and permits in Modesto, answered the way I'd answer them under your house.
Does a vapor barrier help a crawl space in Modesto?
Yes, a vapor barrier over the dirt can almost completely shut off one of the main sources of moisture in a house. That keeps your floor framing drier and keeps damp from working up through the walls into your rooms. For a vented crawl space, a plastic soil cover is the well-studied first step, and that research is general guidance for a Modesto house.
Is sealing my crawl space better than a vapor barrier ground cover?
Usually not as a first step, because a sealed crawl space is a lot more work than a cover. Closing the vents alone doesn't seal it, since ground moisture control, insulation, air sealing and a planned way for the space to dry all have to work together. One university extension guide also advises against a closed crawl space on a lot prone to flooding.
How much does crawl space encapsulation cost in Modesto?
Installed crawl space encapsulation usually costs about $4,500 to $8,000 per job across the US. That's a national figure for a fully sealed crawl space, not our price, and a plain ground cover is a smaller job than that. For your own number, I come out, look under the house and write the estimate.
Who do I call about permit questions in Modesto?
Call the City of Modesto at 209-577-5232 with questions about the city's permit process. The city uses permits to check that work is done properly and meets safety and building codes, and permitted work gets inspected before it's covered. When a job needs a permit, we pull it with whichever office has your address, city or county, and set up that inspection.
What should I check in my crawl space before I call?
Look for standing water, wet wood or soaked insulation, and note whether the foundation walls have vents. If a humidity meter keeps reading around 60 percent relative humidity or higher, treat that as a reason to find the water source, not a diagnosis. If you see standing water near wiring, sewage, framing that's shifted or heavy contamination, stop there and get qualified help.
Other jobs that pair with a crawl space cover
Get your crawl space looked at
Call (209) 222-5441 or send the form, and if a cover won't fix what's going on under your house, I'll say so.