Finding the best insulation for your basement ceiling can be a daunting task. After all, there are so many things you’ll need to consider. What type of insulation should you use? What kind of R-value should it have — or what even is R-value?
These questions can quickly become overwhelming if you’re not a professional. But never fear! Just think of this article as your crash course in basement ceiling insulation. Because, believe it or not, some things are specific only to that surface in your home.
If your basement is the coldest room in your home, you’ll need to think about insulation in terms of heat and moisture protection in addition to its soundproofing purpose. The sooner you figure out your insulating needs, the sooner you’ll be able to select and install your insulation. But before we dive into the subject, let’s take a moment to answer the most basic question. Is insulating your basement ceiling strictly necessary?
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The Pros and Cons of Insulating Your Basement Ceiling
Right off the bat, you might be wondering why you should even insulate your basement ceiling. Couldn’t you just leave it as is? It would certainly be easier — and there’s a chance that insulating your basement ceiling isn’t required by law. Still, there are all sorts of benefits to doing it.
The drawbacks of insulating your basement are pretty straightforward — you might say it’s a waste of your resources. Between the insulation batts and any additional products you might put between them and the drywall, the project can become pretty expensive. Of course, you could decrease the overall cost by ordering only as much as you need and being smart during the installation process. Remember: measure twice, cut once.
Then again, if you’re considering insulating your basement ceiling, you probably have other things on your plate as well. You could be working on the whole house or simply trying to turn an unfinished basement into a liveable space. If you’re trying to insulate your whole house on a tight budget, skimping on the basement would be completely understandable.
Unless local building codes state that you must insulate your basement ceiling, nothing and no one can make you do it. However, many districts do have laws in place that mandate exactly how you need to finish the surfaces in your basement. Before you get overly excited about cutting those corners, I suggest finding out whether insulation is necessary.
Of course, if you want to be able to turn your basement into an entertainment den, you’ll need to insulate it properly. And that’s not even the only reason you might have to insulate your basement. With that in mind, let’s consider why you might need to insulate your basement ceiling and how that might affect the products you choose.
Why Should You Insulate Your Basement Ceiling?
There are three main benefits of insulating your basement ceiling. The most obvious one is that you’d want to keep hot air from escaping and cold air from climbing up into the house. Additionally, you’d have to think about moisture as well as sound passing up through the ceiling.
Most people wouldn’t shell out the cash to heat their unfinished basement. If you have just the bare bones of a room down there, there’s so need to heat it, right? But if you’ve decided not to heat your basement, you should install ceiling insulation. After all, you wouldn’t want to lose the heat from above through the floor.
On the other hand, if you want to use your basement as a living space, you’ll want to insulate the walls. However, ceiling insulation may not be necessary in that case. As long as the walls are insulated, you wouldn’t have to worry about drafts or moisture entering your home.
Since basements are, by their very definition, below ground level, moisture should be one of your primary concerns. If the dampness of the surrounding ground penetrates through the wall and into the insulation, it can create the perfect conditions for mold growth.
Fortunately, that won’t happen if you use the right kind of insulation. More specifically, you’d need to get the kind that won’t absorb water. Alternatively, you can get the kind of insulation that has a built-in vapor barrier or use a separate product to act as one.
When Should You Worry About Noise?
Last but not least, you may have to think of insulation in terms of soundproofing. After all, people use their basements for a wide range of things. You might be considering turning yours into:
- A laundry room so your washer, dryer, and water heater can make noise without disturbing anyone
- An entertainment den complete with a projector and a home speaker setup
- A home gym with treadmills and exercise bikes
- A recording studio or music room with drums or electric guitars
If you wanted to set up any of these things on the first or second floor or your house, you’d have to deal with the noise spreading both through the air and the building structure. However, keeping them in the basement would at least alleviate the floor impact noise transfer. All you’d have to worry about is sealing the doors and insulating the ceiling.
Additionally, there’s one final benefit to insulating and finishing your basement ceiling with drywall. If nothing else, it’ll at least make the room look a bit tidier overall. So, if none of the other reasons I’ve listed sway you, maybe that one will.
Which R-Value Should Your Basement Ceiling Insulation Have?
If your primary goal is to enhance the thermal resistance of your home, your insulation will need to have a high R-value. In fact, you’ll need a minimum value of R-10 for your basement ceiling. The higher the number, the more heat-resistant the surface you’re insulating will be.
All surfaces in your home have an R-value per unit length, as do the individual products they’re made up of. So your ceiling will have an R-value higher than the insulation you use because you’ll also use drywall (among other things) to construct it.
That measurement is not to be confused with the U-value, or the U-factor, which expresses how well a material or structure conducts heat in watts. If you run into that unit while researching building materials, keep in mind that the insulation you’re looking for will need to have a high R-value, but a low U-factor! Fortunately, the insulation you would use in your basement ceiling should naturally have a fairly high R-value.
Remember, while 3.5-inch batts might fill your wall cavities, the space between your ceiling and the floor above will probably be twice as thick. Therefore, it will require thicker insulation, which will naturally have a higher R-value than its thin counterpart. On top of that, the base material of the insulation will also play a part in its ability to resist heat.
Generally, though, most of the products you’ll consider putting between your ceiling joists will have an R-value of 10 or above. If you live in a cool climate and frequently rely on air conditioning, you may even opt for insulation with an R-value of 13 to 25. Once again, you might want to check with your local construction expert before selecting your insulation.
What Type of Insulation Is Best for Basement Ceilings?
As someone who dabbles in construction work, you’re probably aware of the most basic kinds of insulating materials on the market. There’s blanket insulation, which can be made of fiberglass, mineral wool, or even natural fibers like cotton or cellulose.
Those products come in batts and rolls that are just slightly wider than the space between wall studs or ceiling joists. That imperceptible compression should hold the insulation up without your having to affix it to the joists. However, if you want to make sure it won’t budge, you can use wires or fishing lines to hold it up.
Alternatively, if you end up using insulation with paper facing, you could peel off the paper around the edges and staple it to the joists. You can see the process of installation in this video, although on what seems to be an attic ceiling.
As we have established, the kind of insulation you’d need to install in your basement ceiling is dependent on the conditions you’re dealing with. Most basements have the issue of moisture seeping in through the walls and climbing up into the home. Therefore, some kind of vapor barrier may be necessary. If the insulation you use traps moisture instead of blocking it entirely, it might turn into the breeding ground for mold.
Obviously, batt insulation is the traditional solution when it comes to insulating basement ceilings. It may even be mandated by your local building code — but it’s far from your only option. Blown insulation or expanding foam sprays are perfect for insulating your ceiling without taking off the existing drywall.
The Best Basement Ceiling Insulation Materials in 2021
Having reviewed the basics of basement ceiling insulation, let’s take a look at the most popular products people use in that area.
1. Owens Corning Pink Ecotouch Insulation R-19 Faced Fiberglass Roll
After Owens Corning came out with its EcoTouch series of insulation products, its popularity skyrocketed. You see, most fiberglass insulation tends to irritate the skin and breathing passages. That’s why you should wear a mask, protective eyewear, and full-coverage clothing when you work with the stuff. However, Owens Corning found a way to fix that inconvenient part of fiberglass products — and made it formaldehyde-free!
- Individual Faced Roll - 23 Inches Wide x 39.2...
- Idea for use in 2x6 walls, floors,...
- With less dust than other fiberglass...
- Compression packaging from Owens Corning...
Aside from being less irritating than similar products, this blanket insulation is also famous for its recognizable hue. Most insulation manufacturers have distinct colors for their products — for Owens Corning, it’s pink.
The exact blanket insulation comes in many shapes and sizes, but the one you could use on your basement ceiling has one interesting addition — a paper facing. The roll is 23 inches wide and 39.2 feet long, which should cover about 75 square feet in 2 by 6-inch joist framing. Furthermore, the insulation is 6.25 inches thick, which earned it an R-value of 19.
Since this is a blanket insulation roll, you won’t have those annoying gaps that can sometimes happen between batts. You’ll be able to cut your strips to the exact length of the joist. If you end up with some bare areas after you install the insulation, you could plug them with unfaced insulation. The company also makes foam squares you can use to enhance the insulation around vulnerable areas.
- Pink fiberglass roll insulation with paper facing
- 23 inches wide and 39.2 feet long
- 6.25 inches thick
- Effective thermal and acoustic control
- Check the price on Amazon
2. Johns Manville Intl Kraft-Faced R-19 Kraft Roll
The Johns Manville roll insulation should be pretty similar to the product I’ve just described. As far as I can tell, the only difference is that it’s white, instead of pink. And, of course, while it is formaldehyde-free, like the pink insulation, you’ll want to use protective gear with it. As far as I know, itch-free fiberglass remains exclusive to the Owens Corning brand.
- Item Weight: 20.8 lb
- Country of Origin: United States
- Brand name: JOHNS MANVILLE INTL
- Item Dimensions: 26.0"L x 19.0"W x 23.5"H
The roll itself has the same dimensions we saw in the previous product — 39 feet by 23 inches, covering a surface area of 75 feet. At 6.5 inches thick, the insulation is only a quarter-inch thicker than the previous product. You’ll have to compress it a bit to get it into the 2 by 6 ceiling joints. However, that shouldn’t greatly affect its R-value, which is another thing it has in common with the previous product.
The insulation has kraft facing, although there are versions of it without the barrier, like this 15-inch wide roll. Obviously, you’d have to use that one on narrower studs or joists. Also like Owens Corning, Johns Manville has an unfaced insulation product for hand-filling spots you missed.
- White fiberglass roll insulation with kraft facing
- 23 inches wide and 39 feet long
- 6.5 inches thick
- Enhances energy efficiency and air quality
- Check the price on Amazon
3. Rockwool 60 Acoustic Mineral Wool Insulation
If your main goal is to make your home impenetrable to noise, you’ll probably want to use Rockwool mineral wool insulation. It comes in 24 by 48-inch batts of various thicknesses. However, since we’re dealing with the ceiling, an inch or two of mineral wool probably wouldn’t cut it — so we’re going to look at the 4-inch version of the product.
- Mineral Wool Insulation in 6lbs per unit...
- Great as Acoustic insulation or as a...
- Cost effective and Very High NRC Rating,...
- Water repelling - hydrophobic- Class A fire...
The way Rockwool packages its products, you’ll find that the thicker the insulation, the fewer pieces you’ll get in the box. So the thickest version comes with only 3 batts, while the thinnest one ships 12 pieces. That’s simply because the company uses the same boxes for all their batt products.
Now, I’d be remiss if I didn’t mention that thicker products are also more expensive than thin ones. Covering a certain area can be up to three times more expensive if you opt for the thicker insulation.
In any case, all the products I’ve linked to have a density of 6 pounds per cubic foot. The company also makes more and less dense insulation. All of its materials have an excellent NRC rating, as I’ve explained in a previous article. They’re also water and fire-resistant.
- Mineral wool batt insulation without facing
- 24 inches wide and 48 inches long
- Comes in 1, 2, and 4-inch thicknesses
- Sound absorbing, moisture- and fire-repellant
- Check the price on Amazon
4. Acoustimac Acoustic Insulation Eco Cellulose
All of the products I’ve reviewed so far have been acceptable options for insulating basement ceilings. However, from here on out, I’m going to mention some materials you could only use under certain conditions.
For example, I wouldn’t usually recommend using cellulose batts in damp areas. However, if you attach a vapor barrier before putting in the ceiling drywall and use a waterproof barrier under the flooring upstairs, natural fibers would be a fine substitute for irritating fiberglass insulations.
- Shipped by the Case
- Revolutionary Acoustical Material
- Made of 100% Recycled Materials
- People Friendly NO VOC'S
Acoustimac’s Eco Cellulose insulation is another product I reviewed in my previous article about insulation. There, I mentioned the 2-inch version of the 48 by 24-inch batts — but the company also makes 1-inch pieces.
Both products are Class A fire-rated and have a density of 4 pounds per cubic foot. They should be able to prevent air and sound from passing through. And with the help of a good vapor barrier, this insulation should be mold-free for decades to come.
- Six pieces of recycled cellulose batt insulation without facing
- 24 inches wide and 48 inches long
- Comes in 1 and 2 thicknesses
- Sound absorbing and fire-resistant
- Check the price on Amazon
5. Frost King CF1 “No Itch” Natural Cotton Multi-Purpose Insulation
Like cellulose, cotton insulation isn’t exactly what you’d call waterproof even though the product description claims that it’s moisture-, mold-, and fire-resistant. But if you want to build a completely eco-friendly home, you should consider it. It may be significantly thinner than the blanket insulation you saw at the beginning of this list. Still, you should be able to achieve a similar effect by stacking several of these 1-inch batts on top of each other.
- Use For Insulating, Cushioning, And Noise...
- Safe Alternative - No Gloves, Face Mask, Or...
- Cut Or Rip To Fit Pipes And Ducts, Walls, And...
- Brand Name: Frost King
The main benefit of using natural fiber insulation is that you don’t have to worry about harmful particles. You wouldn’t need masks, goggles, or gloves to install these 16 by 48-inch batts. However, they would only fit into especially narrow joists. Additionally, you should keep in mind that these cotton batts come in 1-piece packs, so you can order exactly as many as you need.
- One piece of cotton insulation without facing
- 16 inches wide and 48 inches long batts
- Comes in 1 and 2-inch thicknesses
- Sound absorbing, Class A fire-rated
- Check the price on Amazon
6. Dap Touch ‘N Foam Maxfill Maximum Expanding Sealant 12 Ounces
Lastly, I wanted to talk about products you could use to insulate any hard-to-reach areas around the ducts or close to the walls. DAP sells a variety of expanding foam sprays in 12-ounce cans for different areas and occasions. But the one I wanted to highlight is the MaxFill sealant, which was made to fill gaps that are over an inch wide.
If you use the FoamBeak application nozzle, you’ll be able to direct the foam wherever you need it. You can even use it to add bulk to your drywall. Keep the applicator flush against it and move it down the length until the whole piece is covered. Wait for the foam to cure and attach the drywall as usual.
Now, these cans aren’t the same thing as the foam insulation I mentioned earlier. Still, it’s close enough to get the job done if you stick to small areas. On the other hand, if you wanted to insulate the whole ceiling with a foam product, you’d have to insert it into the ceiling through strategically positioned holes in the drywall. Otherwise, it might drip on the floor.
- 12-ounce can of expanding foam insulation
- Fills gaps that are over an inch wide
- Straw applicator (can be enhanced with a nozzle attachment)
- Check the price on Amazon
How to Install Ceiling Insulation in Your Basement
Depending on what your basement ceiling currently looks like, your application process may vary. If you’ve left the joists exposed for years, you might have to swap out some parts before moving in with the insulation. However, if, upon cleaning the ceiling, you decide that there are no structural vulnerabilities there, you could simply proceed with the insulation.
Now, if you’re planning on combining expanding foam and blanket insulation, I recommend going in with the foam first. After you insulate any air ducts or pipes, you can go in with the batt or roll insulation. Just remember to dress appropriately and wear protective gear if you’re working with fiberglass!
I’ve already explained the process of installing insulation in a previous article. All you’ll need is a utility knife and your own two hands. If the product you’re using has a paper facing, you’ll need to turn it toward you as you push the batts in. After lifting the batts and pushing them into the ceiling, tug them back down until the facing is flush with the joist edges.
The slight compression should help them stay up. However, if building regulations require you to attach them more securely, you can do so now. Either tack the paper facing into the joists or use wires to hold everything up.
What to Use to Cover Basement Ceiling Insulation
Since basements are notorious for being the most humid rooms in our homes, you might want to attach a vapor barrier before the drywall. The sheets of plastic are fitted over the insulation to protect it from any moisture that gets through the drywall. You’ll use a combination of staples and acoustic sealant to attach it to the ceiling joists.
The sheeting can come 8.4-foot wide rolls, so you might need to use tuck tape to hold the different pieces together. If you happen to nick the plastic, you can tape right over it to restore the seal. In the video, you’ll see how you might install the barrier on a wall, but doing the ceiling is pretty similar. You’ll just need some extra hands to hold the sheet up while you staple and tape it.
After you’re done, and before your helpers make themselves scarce, you could add the finishing touch — the drywall. You should never leave the insulation out in the open, especially if it’s made of fiberglass. And leaving the natural fiber insulation exposed would be even worse, as it would soak up all that moisture. So what can you use to cover up the insulation?
Aside from plain drywall, you could use anything from wood paneling, planks, and decorative beadboard to metal sheeting, tin or PVC tiles. And that’s not all — there are other ways to finish a ceiling if you want to make the basement soundproof.
Additional Tips for Insulating Basement Ceilings
Before you put in any of the finishing surfaces I’ve mentioned, there are a few more things you can do to separate the wooden joists from the ceiling surface. For example, you can install sheets of MLV in much the same way you would put in a vapor barrier. I’d even say you could use those interchangeably — unless local building codes say otherwise.
Additionally, you could install resilient channels to decouple the drywall, sheetrock, or plasterboard from the ceiling joists. If you don’t think that drywall can effectively cut down the noise transmission, try the Green Glue sandwich technique. Just fuse two sheets with a layer of Green Glue and attach them to the ceiling joists.
On the other hand, you could construct a drop ceiling with acoustical ceiling tiles. Basically, your options are limitless. And even when you finish the project, you’ll still be able to use any number of acoustic products on top of the ceiling to further increase sound absorption.