Hardly anyone sees the insulation under their own floor. You notice it in the rooms above it, or with a flashlight at the crawl space door.
If the floors never warm up in January, most of all in the rooms right over the crawl space, heat is leaving through the floor. Thin or missing insulation is one cause. Air coming up around pipes and wires is another, so we look at both.
Shine a light along the joists from the access door. Batts that droop, hang by one corner or lie on the dirt have stopped working. Floor insulation only does its job while it's held tight against the floor above it.
Insulation that has turned dark and matted, feels heavy or smells musty has been taking on water. Wet insulation does very little to slow heat, and it holds the water against the wood above it. It has to come out, and why it got wet matters as much as the new batts.
If you can see bare soil under the house, or old plastic that's torn, bunched up or half buried, moisture from the ground is rising into the air your floor insulation hangs in. Plastic over the dirt is part of this job, and it goes down before the new batts go up.
Insulation under a house has one job. It slows the heat moving between your rooms and the crawl space below them, which in most houses is open to the outdoors through foundation vents. In a crawl space like that, the insulation belongs between the floor joists, pressed against the underside of the floor. North Carolina's residential code puts the insulation of a vented crawl space in the same place: the floor.
That's the work we do under the house. We pull out insulation that's wet, fallen or soiled by animals, and we fit new batts between the joists and hold them up against the floor. We lay plastic over the dirt, and we seal the holes where pipes and wires come up through the floor, because batts slow heat but don't stop moving air. Most of our days are spent in attics, so if attic insulation or air sealing would do more for your house, we'll tell you that first.
It helps to know what this job isn't. It isn't crawl space encapsulation, where the walls are lined and the vents are closed, and it doesn't include dehumidifiers, drainage, sump pumps, waterproofing or mold remediation. We don't do that work. If your crawl space has standing water or mold on the wood, that needs a crawl space moisture contractor first, and we'll say so before we price any insulation.
Monday to Friday 8:00 am to 5:00 pm. Saturday by appointment. Sunday closed.
Insulation under a floor rarely just wears out. Something happens to it: water, gravity, an animal or a repair. The cause decides what the fix should be.
Usually it's moisture, with gravity doing the rest. Insulation that takes on water gets heavy, pulls away from the floor and works loose from whatever holds it up. Too few supports will bring it down even in a dry crawl space. North Carolina's energy code requires floor insulation to stay in permanent contact with the subfloor, on supports no more than 18 inches apart. When whole rows are down, ask why before asking how soon they can go back up.
Most often it's summer air, not a leak. A guide written for the U.S. Department of Energy's Building America program explains that fiberglass batts between the joists of a vented crawl space are cool on their underside, and the joist edges are cooler still. Where those surfaces drop below the dew point of the air around them, water condenses, and the guide says damp batts insulate poorly. A plumbing leak or bare, damp soil can soak insulation too.
As a rule, no. The EPA's guide to cleaning up water damage, written for schools and commercial buildings, gives one instruction for wet fiberglass and wet cellulose insulation: discard and replace. So wet batts come out and leave with us. New ones go up once the cause is dealt with, whether that's a leak a plumber has fixed or bare dirt that now has plastic over it.
Because insulation only works where it touches the floor, and it doesn't stop moving air. A Building America guide prepared by the Pacific Northwest National Laboratory says floor insulation has to sit in full contact with the subfloor, with no gaps, voids or squashed spots, and that batt insulation isn't a good air barrier. North Carolina's code calls for the openings around pipes and wires to be sealed, and it doesn't accept fiberglass as the seal.
It does, because soil is rarely dry. The U.S. Department of Energy's insulation fact sheet puts it simply: thick plastic on the crawl space floor keeps ground moisture out of the crawl space air, and so out of the house. The Department's Building America Solution Center says every crawl space should have a polyethylene ground cover, vented or not. Bare dirt keeps feeding damp air to the batts overhead.
Yes, and these are the cases where replacing the insulation is often the whole job. Animals tunnel and nest in it, a slow plumbing leak can soak one area, and anyone working under the house may pull sections down and leave them on the ground. When the cause was a one-time event, the repair is usually limited to the damaged part. Pest control and plumbing aren't our trades, so those get fixed first, by the right people.
Not sure what happened under your floor? Tell us what you can see from the crawl space door, or send a photo, and we'll tell you what we think.
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There are four parts to the job, and your estimate lists the ones your house needs. Some floors need all four. Some need one.
Wet or fallen insulation comes out before any of this goes in.
Batts that are on the ground, hanging loose, soaked or soiled by animals come down and leave with us. Batts that are dry, clean and still tight against the floor can stay, and we'll tell you when yours qualify.
New batts are cut to the joist spacing, fitted around pipes and wires, and pressed up against the underside of the floor with no gaps. Supports hold them there for good, no more than 18 inches apart under North Carolina's code, so they can't sag or drop.
Plastic laid over the soil keeps ground moisture from rising into the air under your floor. It's a plain ground cover, often called a crawl space vapor barrier. The foundation vents stay open, and torn or bunched-up old plastic comes out first.
Every pipe and wire that comes up through the floor leaves a gap around it, and crawl space air rides up through those gaps into your rooms. We seal them before the new batts cover them, since batts slow heat but don't stop air.
Here is how a crawl space insulation job goes with us, start to finish.
Call, text or use the contact form. Tell us the size of the house and what you've noticed in the rooms or under them. A photo from the crawl space door helps a lot.
Most floors we price from the square footage, with no visit. If the crawl space needs a closer look first, we make a special visit. The estimate is free, and it covers what the floor needs and nothing else.
The wet or fallen insulation comes out, the floor leaks get sealed, the plastic goes down and the new batts go up. Before any work starts, the crew tells you what they see down there and whether anything changes the job.
Usually, when the floor is bare or the old insulation has failed. The floor is a bigger part of your home's shell than most people think. A guide prepared for the U.S. Department of Energy's Building America program notes that floors can make up a quarter to a third of a house's outer surface, and that flaws in the insulation and air barrier over a vented crawl space lead to uncomfortably cold floors and higher heating and cooling costs.
We won't promise you a number. ENERGY STAR's familiar estimate, an average saving of about 15 percent on heating and cooling costs, comes from sealing air leaks and adding insulation in the attic, over crawl spaces and in a few other easy-to-reach places together, not from the floor alone. If the attic would do more for your house, we'll tell you to start there.
Savings vary. Find out why in the seller's fact sheet on R-values. Higher R-values mean greater insulating power.
Dry is what makes it last. Batts hung over damp, bare dirt take on water and come down. That's why the ground cover and the floor leaks are part of the same job, and why we'll tell you plainly if your crawl space has a water problem that new insulation can't fix.
A vented crawl space sits outside the heated part of the house, so the floor over it is a floor over unconditioned space. North Carolina's energy code sets the minimum for that floor at R-19 in climate zones 3 and 4 and R-30 in zone 5, the mountain counties. ENERGY STAR's figures for floors in existing homes match: R-19 in zones 3 and 4, R-30 in zone 5. Not sure which zone you're in? Our guide to attic insulation R-value in North Carolina lists every county's climate zone.
Those code numbers are minimums for new homes. An older floor is limited by its joists and by what's already there, so the R-value printed on the new batts goes on your estimate. The Federal Trade Commission's R-value Rule says installers must give customers a contract or receipt that shows how much area was covered, how thick the insulation is and its R-value. Ask every company you call for those three lines.
Most floor jobs start with taking something out. Batts that have fallen, soaked up water or been torn up by animals come down first, along with the scraps lying on the dirt under them. All of it leaves with us.
Not all of it has to go. Batts that are dry, clean, full thickness and still tight against the floor are doing their job, and we leave them. What matters is finding out what ruined the rest. New insulation hung where the old insulation fell is likely to end the same way, so the cause gets named on your estimate along with the fix.
Two things we point out and leave alone. Old pipe wrap may contain asbestos, and the EPA says you generally can't tell by looking, so it stays put for an asbestos professional. Soft or rotted wood is structural repair, which we don't do, and we'll tell you about it instead of covering it up.
A crawl space vapor barrier is a sheet of polyethylene plastic laid over the soil under your house. It keeps the moisture in the ground from rising into the air and the wood above. You'll also hear it called a moisture barrier or a ground cover. The U.S. Department of Energy's job aid for weatherization installers calls for sheeting no thinner than 6 mil, with a perm rating no higher than 0.1.
In a vented crawl space it works alongside the vents, not instead of them. North Carolina's code lets a vented crawl space with covered soil get by with a tenth of the vent area it would otherwise need, as long as the vents still cross-ventilate. So the plastic goes down, the vents stay open and the walls aren't lined.
Old plastic doesn't always have to go. If what's down there is whole, lies flat and covers the dirt, we'll tell you to keep it. If it's torn, bunched up or half buried, it comes out before the new sheet goes down.
We don't print prices, but we can tell you what moves them. Most floors we price from the square footage: you tell us the size of the house, or we work it out from your home's footprint. Then the price follows what the floor needs. How much old insulation has to come out first. Whether the dirt needs plastic over it. How many pipes and wires come up through the floor. How much headroom there is under the house.
If we can't price it honestly from the numbers and what you've told us, we make a special visit before we price it. We believe in honest pricing, and we don't upsell. If the batts under your floor are fine and only a few have dropped, the estimate says that, and it's a small one.
For most houses built over a vented crawl space, yes. The floor is all that separates your rooms from the outdoor air under the house, and North Carolina's code puts the insulation of a vented crawl space in that floor. An older house may have less, or none, or batts that have fallen. Whether yours needs new insulation depends on what's there now and whether the crawl space is dry enough to keep it in place.
Batts. The U.S. Department of Energy's crawl space fact sheet describes batts cut to the joist spacing as the usual choice under a floor, and batts are what we install there: fitted between the joists, pressed against the subfloor and held up by supports. We don't install spray foam or rigid foam board under floors. Your estimate names the batts and their R-value.
Up, toward the floor, in most of the country, according to the U.S. Department of Energy's crawl space fact sheet. The part people miss is fire. The Department's general insulation fact sheet says kraft paper and standard foil facings have to be covered, and that insulation left exposed should be unfaced or carry the right flame spread rating. So paper left hanging down toward the dirt deserves a second look.
Usually, yes, because the two do different jobs. The plastic on the ground keeps soil moisture out of the crawl space air. It does nothing to slow the heat moving through your floor. Insulation does that, and it has a better chance of staying dry over covered ground. If the plastic is torn, thin or missing, new plastic goes down before the new batts go up.
Yes. Wet, fallen or animal-soiled insulation comes out and leaves with us, and the cause is named before new batts go in. Dry batts that are still tight to the floor can stay. If the wood above the old insulation is soft or has mold on it, that's work we don't do. We'll point it out and tell you who to call before any new insulation goes up.
Most floors are priced from the square footage. Give us the size of the house, or your address so we can work it out from the footprint, and tell us what you've seen under it. Photos from the access door help. If the crawl space needs a closer look before we can price it honestly, we make a special visit. The estimate is free, and we don't upsell.
Not for work done now. According to the IRS, the Energy Efficient Home Improvement Credit covers improvements made through December 31, 2025, and nothing later. North Carolina's Weatherization Assistance Program, run by the state's Department of Environmental Quality, serves income-eligible households, and its services may include insulation. You apply through a local weatherization agency, not through us.
Anywhere in the state. Charlotte, Raleigh, Greensboro and Wilmington are all inside our service area, and so is every town between them. Call or use the contact form, and tell us the size of the house and what you can see from the crawl space door.
Attic Insulation
North Carolina's energy code requires R-38 in a new ceiling, and ENERGY STAR recommends more for existing attics. See both numbers, which climate zone your county is in and how many inches each R-value takes.
Air Sealing
Thick insulation over a leaky ceiling is like a wool sweater in a stiff wind. Learn why sealing has to happen first, where leaks hide in attics and ducts, and what a sensible job looks like.
Attic Insulation
Houses built before the state's 1978 energy rules often have little in the attic and nothing in the walls. Learn the safety checks to make first, the leaks old framing hides and the order to do the work in.
Air Sealing
A step-by-step look at the audit visit: the interview, the bill review, the blower door and the infrared camera. Plus what a useful report contains, and the honest cases where you do not need an audit at all.
You'll probably never crawl under your own house to check the work. So judge crawl space insulation installers by what they tell you before the job starts, and hold us to the same test.
New batts hung where the old ones fell will likely come down the same way. Before we price anything, we look for the reason: damp air, bare dirt, a leak, animals or supports that were never enough. That reason decides the fix. When it's ours to fix, the estimate says how. When it isn't, like a plumbing leak or a water problem, we tell you who should handle it first.
Not every crawl space needs everything on this page. If the plastic on the ground is sound, it stays. If most of the batts are dry and tight to the floor, we replace the ones that aren't. And if the attic would do more for your comfort than the floor, we'll tell you so, even when that means a smaller job for us.
Insulation Pros is family owned and operated, and we work in every part of North Carolina. Floors come alongside our main work, which is in the attic: blown-in insulation, old insulation vacuumed out and replaced, and air sealing. We do wall insulation and garage insulation too, so one estimate can cover more of the house. If the cold floor is in a room over the garage, that's a garage job, not a crawl space one. Our Google reviews are public, so read them first, then call or text us or use the contact form.
North Carolina
Open in Google Maps (opens in a new tab)We're a family owned and operated insulation company, and we do crawl space insulation for homeowners all over the state. Pick your town to see what we do nearby, or browse all of our service areas.
Call (336) 870-3893 for a free estimate.
Homeowners looking into crawl space insulation often ask about these services as well.
Sealing the gaps between your rooms and the attic, and leaky ductwork, so the air you pay to heat and cool stays inside.
Insulation blown into the closed walls of an existing house, batts in open walls for additions, remodels and new builds, and garage walls and ceilings.
Blown-in fiberglass attic insulation, added to the depth your home needs, to even out hot and cold rooms and cut wasted heating and cooling.
We serve homes across North Carolina. These are the largest towns we work in.
Alamance County
Buncombe County
Cabarrus County
Cumberland County
Durham County
Forsyth County
Gaston County
Guilford County
Mecklenburg County
New Hanover County
Onslow County
Orange County
Pitt County
Wake County
