Damp dirt, a musty smell or torn old plastic under the house? We cover the ground properly and check where the water comes from.
A crawl space vapor barrier in San Rafael is a sheet of plastic laid over the bare ground under your house, and when it's installed well, it helps minimize the ground moisture and soil gases, such as radon, that come up from the dirt.
Most people call because something under the house doesn't seem right. The dirt looks dark and wet, the floors above smell a little stale, or the old plastic down there is torn, bunched against one wall or missing, with boxes sitting on bare ground. Before anyone lays new plastic, I go under and figure out what's actually going on.
The price mostly follows the size of the crawl space, how low and tight it is to work in, and how much has to come out first, from old plastic to debris. The schedule turns on that same prep, and on whether water from the yard has to be fixed before the plastic goes down. The written estimate I give you after I've been under your house has the number for your job.
Laying plastic sounds simple, and mostly it is. These are the details that decide whether it keeps working after the crew leaves and someone crawls in to service the furnace.
Extension guidance written for North Carolina says crawl space humidity should stay below 60% and suggests a dehumidifier when it runs higher. It comes from another state, so treat it as a guide, but a reading under your house tells us whether a dehumidifier belongs in the plan or the plastic can carry the job.
Federal weatherization guidance calls for plastic at least 6-mil thick, which is six thousandths of an inch. Thin sheeting tears the first time someone drags a toolbox across it, so when you compare quotes, ask what thickness each one uses.
Loose edges let moisture slip around the sheet, so the plastic is usually either lapped up the foundation walls and piers and fastened there, or staked to the ground at the edges. On paths that get walked, such as the way to your furnace, an extra layer or a vinyl runner can go down.
Here's how a crawl space job runs, from your first call to the walk-through at the end, and who you'll be dealing with at each step.
Call (628) 234-2144 or use the form. It helps if you know whether your crawl space has vents and where you've seen wet spots, puddles or water collecting near the foundation.
I come out myself and get into the crawl space. I look at the ground, the old plastic, the vents and the drainage outside, note anything that has to be fixed first and write up the estimate.
If you go ahead, we handle any permit the job needs. Then our crew clears out debris and old plastic, lays the new cover over the ground and secures the edges, with me on site running it.
Before we leave, I show you what we did and point out anything the plastic can't fix, like a low spot by the foundation that still needs a drainage change.
A ground cover helps, but it won't stop water running in from the yard. So when I'm under your house, I look at the drainage and grading along with the plastic, and you hear from me if there's more to do. I'd rather tell you that up front than lay a fresh sheet over ground that'll be soaked again after the next heavy rain.
We work in order. Outside water gets sorted out first, then the plastic goes down. If moisture is showing up somewhere other than the crawl space, that's our vapor barrier installation work. And if the rooms above still feel drafty once the ground is covered, the fix is usually up top, where attic air sealing closes the gaps that pull air through the house.
Leaving the vents as they are and covering the ground is the simpler job. It's usually where I start in an older home, as long as water from the yard is under control.
Closing the vents makes the crawl space part of the house, so the cover and how the space stays dry matter more. It's a bigger job, and it only makes sense once outside water is handled.
Send the form and we'll get back to you within one business day to set a time. I come out, go under the house and write up your estimate, which is free, done at your home and comes with no obligation to go ahead.
(628) 234-2144In San Rafael, the Building Official issues permits for work that builds, alters or repairs a building. The city's rules don't spell out whether a ground cover on its own needs one, so I find out before we start. If yours does, we pull the permit and set up the inspection, which the city lets you apply for and schedule online.
The vent choice matters here too. California's energy rules say an unvented crawl space must have a vapor retarder, a moisture-blocking layer, over the dirt floor, because it keeps moisture from getting in and protects the insulation from condensation. So in a vented crawl space the plastic is a smart move, and in a sealed one it's required.
Under older homes around here, we often find plastic that's torn, shifted or buried under stored boxes, and sometimes none at all. We do the same work in nearby cities like San Anselmo and Novato.
I spent my first years in the trade insulating new houses, where everything is open and nobody's moved in yet. I started this business in 2023 to work on lived-in homes around San Rafael, and three years in, the lesson still holds. Problems get fixed first, or the new material doesn't do much.
I come out myself to look at your crawl space and write the estimate, and our crew does the install with me on site running it. We're licensed and insured, and our work is backed by our satisfaction guarantee. If you'd like me to take a look, call (628) 234-2144 or send us a message.
When moisture is getting into walls or other parts of the house, not just rising from the ground, a vapor barrier there may be the right fix.
Sealing the gaps up top keeps warm air from leaking out through the attic, which can draw damp air up from below.
We're based in San Rafael and cover crawl spaces in homes across Marin and nearby, from Petaluma down to Strawberry and over to Richmond and Berkeley. If your city isn't named on the site, call and ask.
Yes. Building science guidance says the plastic ground cover should go in whether the crawl space is vented or sealed. That makes the cover and the vents two separate choices, so keeping your vents doesn't mean skipping the plastic.
No. In a vented crawl space, most of the moisture usually comes from water outside, such as poor grading, no drainage around the foundation or sprinklers soaking the ground by the house. Plastic slows moisture coming up from the soil, but it can't keep that water out, which is why I check outside too.
There's no set price, because every crawl space is different, so I give you a written number after I've been under yours. Besides size and access, your choices move it. Heavier plastic, a dehumidifier or sealing the vents raise the total, while a vented crawl space with good drainage keeps the job simpler.
Clear out anything stored in the crawl space so the plastic can cover every part of the ground. Old boxes, lumber and debris all have to come out first. If there's something down there you can't move yourself, tell me at the estimate so we can plan for it.
You usually don't need to leave, because laying plastic has none of the fumes that come with spray foam. How long the crew is under the house depends on its size, how easy it is to move around down there and how much clearing comes first. I'll go over that with you at the estimate.
Possibly. The city's permit rules don't spell out a ground cover on its own, so I check for your job before we start, as covered in the San Rafael section above. If it does need one, you don't have to apply yourself, because we pull it.
Often it has to be a contractor licensed by the Contractors State License Board. The state requires a license when a project needs a building permit, uses additional workers or costs $1,000 or more in labor and materials. A job with a crew under the house usually meets at least one of those.
Torn or shifted plastic is hard to judge from the hatch, so call (628) 234-2144 or send a message and one visit will settle whether a new cover is enough.
