Crawl space vapor barrier in Mandan ND - the dirt covered and the damp kept down
Musty smell coming up through the floor, or bare dirt under the house? We cover the ground and walls so the damp stays down there.
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Does my crawl space need a vapor barrier?
A crawl space vapor barrier is a heavy polyethylene sheet, a tough plastic, that covers the bare dirt under your house and runs up the foundation walls and piers. In Mandan we put one in to keep moisture from the soil out of the air under your floors, either as a ground cover in a vented crawl space or as one part of sealing the whole space up.
Most people call because there's a musty smell coming up through the floor, the floors feel damp, or somebody went down to fix a pipe and found bare dirt or an old sheet of plastic in shreds. The price moves with how big the space is, how heavy a liner you want, whether we lay a liner on its own or seal up the whole crawl space, and whether anything has to be fixed first, such as water coming in or years of junk to haul out. The schedule turns on those same things plus how much room there is to crawl around, and once I've been down there myself I'll put all of it in your estimate. If the floors above stay cold after that, crawl space insulation is usually the next conversation.
How we put in a crawl space vapor barrier
I start by going down there myself, because if water's coming in, the wood's gone soft or something's been living under your floor, I'd rather tell you now than bury it under plastic. Then we help you choose between a liner on its own and sealing up the whole crawl space, and if there's a furnace or water heater down there we plan around it from the start so it can still be reached and serviced. Our crew hauls out the old liner, the rocks and whatever the previous owner decided to store down there, smooths the ground so nothing pokes through, and lays the sheet over every bit of dirt and up the foundation walls and around the piers. I check the whole thing before we leave, and we clean up after ourselves so the only sign we were there is the new liner.
A crawl space liner is one kind of vapor barrier installation, and we put those in walls and basements too. Cold air leaking in low in a house usually means warm air is leaking out the top, so attic air sealing often helps the floors and the power bill more than people expect.
Crawl space vapor barrier permits and rules in Mandan
The City of Mandan requires a permit for any structural alteration and for residential construction over $2,000. Its list names furnace changeouts but says nothing about vapor barriers, so whether your crawl space job needs a permit isn't settled, and the city is the one that decides. Those rules reach 2 miles past city limits, so living just outside Mandan doesn't get you out of them. When a job needs a permit, we pull it and set up the inspections, which the city includes with the permit at no extra charge, and if you're not sure about yours, ask and I'll find out.
We're based in Mandan and do a lot of work in Bismarck, along with plenty of other cities around them. The crawl spaces we see on jobs around Mandan and in Bismarck are often under older houses, low and tight, with a torn sheet of plastic or nothing at all over the dirt. North Dakota's environmental quality department points to the federal advice that every home below the third floor be tested for radon, a gas you can't see or smell, so a simple test is the only way to know if you have it.
Crawl space liners up close
Get a written estimate for your crawl space liner
We get back to you within one business day to set a time, and then I come out, go down in the crawl space and write the estimate myself. It's free and done on site, with no obligation to book.
(701) 299-5063Crawl space questions from Mandan homeowners
How do I decide whether my crawl space should be vented or sealed?
Sealed is usually the better choice when the floors above are cold or pipes run through the crawl space, and a liner in a vented space is enough when you mainly want the dirt covered and the damp down. Closing the vents and air-sealing, insulating and conditioning the space, so it gets a little heated air like the rest of the house, can cut condensation on cold floor joists and, in cold climates, help keep pipes from freezing. Those gains come from the whole package, not the plastic alone, so it's a bigger job, and I'll tell you which way I'd go once I've seen yours.
How much does a crawl space vapor barrier cost near Mandan?
In the Bismarck area, a 12-mil vapor barrier with a commercial dehumidifier in a 1,500 square foot crawl space usually costs about $5,200 to $9,600. That's what this work typically runs around here, not our price, and the mil number is just the plastic's thickness. Your own number comes from the estimate I write after I've been down in your crawl space.
What is the best vapor barrier thickness for a crawl space?
A thicker, reinforced sheet is the more durable choice, and basic 6-mil plastic is the lighter one. General guidance, from an older reference, says the 6-mil sheet needs protecting where workers crawl over it to reach equipment, so with a furnace or water heater down there you either go with the tougher sheet or add protection along that path. In a crawl space nobody ever goes into, I don't push the heavier sheet.
What changes if my furnace or water heater is in the crawl space?
If the crawl space gets sealed and there's a natural-draft furnace or water heater down there, the older kind that lets its exhaust rise up the flue on its own, guidance calls for a combustion safety test afterward. The test checks that the fumes go up and out instead of back-drafting or spilling into the house. That's why I want to know about the equipment before I write the estimate, so the test and the liner around it are planned in from the start.
Do we have to leave the house while you put in a crawl space vapor barrier?
Usually not for a liner on its own, because it's a plastic sheet and there's nothing to cure or air out. If you're sealing the crawl space and the walls get spray foam, I'll tell you up front when you can come back inside, what we call the re-entry time. Kids and pets can stay either way, as long as they stay out of the hatch.
What should I ask a contractor before they put in a crawl space vapor barrier?
Ask how they join the sheets and how they keep the liner on the walls. Guidance calls for overlapping every seam, sealing the seams with a sealant made for the liner when the crawl space is sealed, and using fasteners on the walls where practical so the liner stays attached. Those are fair questions to ask us at the estimate, too.
Get your Mandan crawl space looked at
Call (701) 299-5063 or use the form, and if you know roughly how big the crawl space is, whether it has vents and whether a furnace or water heater sits down there, I can plan the visit before I show up.