Effectively soundproofing a floor involves eliminating or replacing the passageways or building materials that sound travels through, and creating additional barriers to the sound transmission using various soundproofing materials.
Knowing What Noise to Suppress or Eliminate
There are 2 types of noise you need to suppress or eliminate for quieter rooms, and ultimately, a quieter house and a more comfortable living environment. They are 1) Impact Noise and 2) Airborne Noise. By soundproofing the floors in your house/apartment/condo/rental you will be addressing both.
Impact noise is also called ‘footfall noise’ but the name really covers anything hitting the floor with enough force to create a sound. This sound moves through the air cavity and ceiling below. It will also transfer through the framing to adjacent rooms and to the rooms below. Some of the more obvious examples are walking in the room, moving furniture, dropping things, or bouncing a ball. Less obvious, but just as annoying, is the sound of your dog’s claws scrabbling on the hardwood floor chasing the ball.
Airborne noise, as the name implies, is any noise that carries through the air and can be heard on the other side of floors, ceilings, or walls. This noise–such as conversation, car alarms, music, the TV, or someone’s kid practicing to be the next great rock drummer–is a sound wave that transmits through the air. Occasionally–as with the rock drummer–you will get the combination of airborne noise and the transfer of impact noise from the same source.
Soundproofing Floors In the House You Own
If you own your house (or live there with the mortgage company’s permission), your soundproofing options are usually only limited by your budget and need for quiet surroundings. Quite likely a bachelor trying to start her/his own band is less in need of soundproofing than a shift worker. The absolute best time to soundproof your floors happens to be the same time you are already spending money on new flooring. You can make the room, or entire house, quieter for a relatively small additional investment.
NOTE: Whenever you have any of your sub-floor exposed for any reason, take the time to screw it down to the floor joists. Use 2 1/2″ deck screws and make sure you countersink them to get the heads below the wood surface. Doing this will eliminate floor squeaks. It will also eliminate the possibility of self-inflicted wounds if your new floor squeaks because you did not take this simple soundproofing step.
Soundproofing Hardwood and Laminate Floors
Assuming that you are replacing the existing flooring with hardwood or laminate, you have choices of soundproofing materials. From the many choices of underlayment available I think that Quiet Walk Plus–manufactured by MP Global–will give you a high quality product which provides the versatility to use almost any type of flooring.
It is specifically designed for floating floor applications such as laminates, hardwood, and engineered wood floors. But it is versatile enough to be used under 5 mm+ thick vinyl, Luxury Vinyl Tile (LVT), Wood Plastic Composite, and Stone Plastic Composite (WPC/SPC) planks. The vapor barrier self-seals around fasteners (if you are nailing hardwood). It is a proprietary blend of synthetic materials with an STC rating of 66, an IIC rating of 77, and a thickness of 3.1 mm.
The vapor barrier protects the flooring and accepts glue for glue-down floors while the fibers in the product will absorb any liquid that gets under the floor. This also makes it a good product for concrete floors if you are planning new flooring in your basement.
Quiet Walk Plus has one taped edge to ensure the overlaps of each section will will remain consistent, and not move around while the flooring is being installed. Being as anal as I am, I would also invest in a roll of Vapor Barrier Tape or Tuck Tape to reinforce the seams and tape the last edge against the wall. The Seam Tape is almost 4″ wide so if you have a little trouble taping a perfectly straight line, it will let you run a bit crooked and still get the gaps sealed. Once the underlayment is properly installed you can install your floor.
Just a few notes about putting down the flooring:
- If you are nailing your hardwood, keep in mind that the nails will transfer some sound to the floor, and therefore, some impact noise–but it will be greatly reduced.
- Laminate floors are always ‘floating’. The underlayment will greatly reduce, if not eliminate, the creaking and popping noises that laminates sometimes make.
You will see that the AbsorbaSound recommended in the following ‘Ceramic Tile Floors’ section can be used for the same flooring products as the Quiet Walk Plus. Their soundproofing capabilities are comparable but the Quiet Walk Plus is less expensive because it does not require glue, and the installation process is quicker and easier.
Soundproofing Ceramic Tile Floors
Ceramic tile flooring must be glued down, then grouted. Which, of course, means that you require different underlayment. And a plywood sub-floor. This provides the rigidity necessary to prevent the tile grout–or the tiles themselves–from cracking or becoming loose after installation. (Particle board, OSB, or chipboard have too much deflection specially if floor joists are more than 12″ on center.)
If you need to install a plywood sub-floor it is best to lay it right over your existing material–if possible. You can increase the soundproofing by using Green Glue Noiseproofing Compound between the layers of sub-floor. Works great for both impact noise and airborne noise. Follow the instructions and screw the new plywood layer into the floor joists. Screws should be 4 – 6 inches apart.
AbsorbaSound by ME Global available from Home Depot will do the job. Made from 100% recycled rubber in various thicknesses from 2 mm to 12 mm. This product is glued directly to the sub-floor and tile is applied onto the underlayment. 5 mm thickness should provide an STC rating of 59 and an IIC rating of 56.
Like the Quiet Walk Plus, AbsorbaSound is a very versatile product. It can also be glued directly onto concrete floors. You can use it under hardwood, laminate, and engineered vinyl flooring–glued, nailed, or free floating.
Soundproofing Carpet Floors
Carpeting, because of its thickness and construction, starts out as a better sound suppressor than any type of wood or tile product. To make it even quieter when replacing it, you can put down a soundproofing membrane before the pad and carpet. I mentioned the versatility of Quiet Walk Plus. It is also an excellent product for adding soundproofing to rooms where you are installing carpet. If it is your product of choice for all of your floors, the problems of flooring heights is easier to solve. You, or your carpet installer, can roll it out and tape it down before the carpet pad and rug are installed.
Your flooring supplier will give you more information than you want–about carpet and padding. (If you let her.) Make sure you ask about noise transmission of both the padding and carpet. Try to choose products that will balance all of your goals like style, longevity, colors, and pad characteristics with soundproofing. If you use the Quiet Walk Plus, or any other noise reduction product, it will be an easier decision because you have already dealt with a large part of your soundproofing needs.
You might also want to consider Soundsulate 1/2 lb. Mass Loaded Vinyl for soundproofing. It is only 1.27 mm thick with an STC rating of 20. If total thickness of the flooring is an issue (such as concerns about removing and replacing baseboards) this product may be the right choice for you. It is easy and quick to install, does not require gluing or fastening of any type, and at 1/2 lb. per square foot, it will stay where you put it.
Soundproofing Linoleum Floors
Replacing vinyl flooring and soundproofing at the same time presents different challenges because it is generally glued down to a smooth surface. Do NOT try to remove the old vinyl flooring–unless you have way too much time and need the frustration. The easiest, and most efficient, way to soundproof a floor under sheet vinyl is to roll the Quiet Walk Plus or Mass Loaded Vinyl over the existing floor. Install 1/4″ G1S (Good One Side) plywood over the soundproofing to provide a smooth, level surface, and glue down the vinyl. Self-sticking floor tiles also require the same type of surface. If you are concerned about the original floor being lumpy–use thicker plywood to ensure level.
Another option–either by itself, or in addition to the other soundproofing, is to use a double layer of 3/8″ plywood with Green Glue spread between the layers. Green Glue is an excellent soundproofing product when used by itself, and only enhances whatever else you are using. It is great for decoupling sound penetration from one space to another.
Soundproofing Floors from Beneath
If you are not removing your existing flooring, or if you want to add even more soundproofing, you can add material between the floor joists or to the ceiling of the first floor if you live in a 2 story home.
Unfinished Basements and Crawl Spaces
If your basement or crawl space is unfinished you can install a product like RoxulProRox SL 960 Rockwool between the floor joists. This product is semi-rigid so if you cut it a bit wider than necessary, it should friction fit between the joists and stay in place until you can get some support under it. It is not supposed to sag, but in my experience, gravity works.
Two options for support are Woven Duct Strap or Adjustable Telescoping Speedi-Hangers from Home Depot. If you are doing a large area, choose the Duct Strap. It is inexpensive, can be cut to length, and then stapled, nailed, or screwed between joists about every 2 feet. For smaller areas the galvanized steel Speedi-Hangars are more expensive, adjust from 10″ – 24″, have an integrated nail on each tab, and are easier and quicker to install.
If you have to work around pipes, ducts, and electrical wiring, this can be a time consuming installation but with patience, perseverance, and a tube of good caulking to fill the holes where the cuts were not quite right you should be able to do a good job.
There is no need to fool around between the joists if you plan to finish the ceiling with drywall, or by hanging a T-bar ceiling. You can attach the RoxulProRox SL 960 Rockwool to the bottoms of the joists; then apply the finish.
T-bar ceilings are fairly easy to deal with. You can usually remove the tiles and install your soundproofing product by working around, and between, the grid. (Occasionally the grid will have to come down if the hangers are too short to give you room to get the product where you want it.) While you have the tiles out, it may be the opportune time to replace them. Normally it is not necessary to change the grid. The 3/4″ thick T-bar tiles at Home Depot are advertised as having ‘High sound absorption and sound blocking properties’. Even the standard tiles will cut down the sound, and there are many designs to choose from.
Ceilings with a drywall finish do not allow access to the floor joists unless you plan to remove it. Few people do. One option is to scrape the texture off the existing drywall, then add another layer of 1/2″ drywall with Green Glue between the layers. Another option is to install rigid insulation (RoxulProRox SL 960 Rockwool STC rating up to 46, Owens SoundproofingInsulation-STC rating of 18) on the existing drywall, then cover it with new drywall.
You can also cut a small hole in the existing drywall (approximately 3″ x 2″) and blow the cavity full of Cellulose loose fill insulation. Cellulose has an STC rating of between 44 and 68 depending on thickness and density. You can probably rent a blowing machine from wherever you buy your product. Make sure you can get a smaller flexible hose. When blowing push the hose as far into the cavity as possible, then slowly extract it as you fill.
Make sure you turn the air down or it will come back out of the hole as fast as you put it in. I would much rather patch a few small drywall holes than re-drywall, tape and mud, and paint an entire ceiling. Or you can have a professional insulation company do the job. And it might be important that you do not lose 2 – 4 inches of ceiling height which will happen when building down the floor joists.
Note: Please see our article on How to Soundproof a Bathroom for a little information on how to patch those drywall holes.
Soundproofing Floors When Building
When designing a new house you can incorporate any, or all, of the above suggestions. Your builder and/or architect will doubtless have more ideas, and probably their own favorite types of soundproofing products. Do your homework and make sure you get the soundproofing insulation where it needs to be. It is way easier, and usually less expensive, to get it done before the house is finished.
If you are convinced your three-year-old will be the next Ringo Starr, then soundproof hell out of the section of the house you expect to turn into the music room. If it never happens–so what. If it does, and you don’t soundproof it now, it will be much more painful to do it later.
NOTE: ALL OF THE FOLLOWING SOUNDPROOFING SUGGESTIONS CAN BE USED IN YOUR OWN HOUSE IF YOU ARE NOT CHANGING THE FLOORING OR DO NOT WANT TO DEAL WITH SOME OF THE MORE INTRUSIVE SUGGESTIONS ABOVE.
Soundproofing Apartment, Condo, and Rental House Floors
Almost all of the following suggestions are fairly non-intrusive because you will probably encounter more restrictions from landlords, condo strata councils, and owners. Unless you can get permission to do some ripping, tearing, and re-modelling, your soundproofing efforts will likely be limited to some of the following suggestions. Having said that; when, or if, some or all of the flooring is being replaced for whatever reason, you should lobby hard to be able to use some of the soundproofing ideas and products mentioned above.
Soundproofing Hardwood and Laminate Floors in Rental Units and Condos
Seems like when I was young (long ago and far away) almost every house I was in had hardwood floors with an area rug about 12′ x 12′ right in the middle of the room. You can do the same thing. To help with soundproofing add a Rug Pad USA 3/8″ thick, rubber-backed, felt pad under the new carpet.
The dense felt not only makes your rug more comfortable to walk on; it provides good noise reduction and has acoustic benefits as well. Although there are many size choices you may have to trim the pad a bit. Depending on the type of carpet you get, it may be necessary to invest in some Sugarman Creations Double Sided Carpet Tape. Some synthetic rugs are too slick to stick to the felt fibers.
If you have a rocking chair, or a noisy recliner in the room, and the area rug does not reach all 4 corners, it is probably a good idea to invest in a smaller area rug complete with carpet pad just to fit under it. This will cut down on the impact noise transferring into the room below.
Soundproofing Ceramic Tile Floors in Rental Units and Condos
Generally ceramic tile is found in entrances, bathrooms, and kitchens. Many people have small rugs at the entrance doors to catch dirt and moisture before it get tracked throughout the house, and to set boots on. For sound suppression, consider getting a larger rug and a RugPad underlay. This will certainly help deaden the sound of stamping boots. (Note: Make sure you open the door and measure the distance between the floor and bottom of the door slab in two or three locations. There is no sense buying a rug and pad that total 3/4″ thick when you only have 1/2″ clearance.)
Balancefrom Puzzle Exercise Mat can be used in all 3 locations. It is moisture resistant and cleans easily. It has a non-slip surface and comes in 3 colors. Most importantly it absorbs sound and vibrations. You can also pack it up and take it with you when you move. For more soundproofing you can buy Mass Loaded Vinyl to put down first. The vinyl will guarantee you an STC rating of 18. It would be a good idea to also have a roll of Carpet Tape which works on virtually any surface, is easy to remove, and will not damage your flooring. Just in case things move around more than you want them to.
Personally, I would stay away from any kind or rug or carpet in the bathroom. Too many ways for it to get wet, smelly, and moldy–some of which do not bear thinking about. Stick with the Balancefrom Puzzle Mat. It is easy to clean but if water does get under it, you can remove and replace all, or part, of it in minutes. You can also find more Puzzle Mats on Amazon if you prefer more color choices. Be sure to look closely at what they offer. Some do not have an edge finishing strip; nor are they as moisture resistant.
Soundproofing Carpet Floors in Rental Units and Condos
Carpeted floors are already better at sound suppression than wood, laminate, or tile because of the nature of the material and the existing under pad. If you want more soundproofing you can use another area rug complete with RugPad underlay. Or you can use the Balancefrom Puzzle Exercise Mat; either for the complete room (like a kid’s room or craft room), or in certain areas such as under a rocking chair or floor-mounted speakers. You might want to buy a small amount of Puzzle Mat first to make sure it will stay together on the rug. I have never tried it, but I suspect there could be a problem on a rug with a longer nap.
You can always roll out Mass Loaded Vinyl first–then the pad, then the carpet–if you want extra soundproofing. This may be a good idea if your are really annoying the neighbor below you–or the neighbor is really annoying you.
Soundproofing Linoleum Floors in Rental Units and Condos
Vinyl floors act pretty much like tile floors. Vinyl is glued directly onto the sub-floor and transfers both airborne noise and impact noise easily without much sound suppression. You can use either carpeting with the RugPad underlay or the Balancefrom Exercise Puzzle Mat. With, or without, the Mass Loaded Vinyl.
I strongly suggest that you try to cover the entire area, rather than just part of the room–both for the soundproofing value and to avoid a tripping hazard. Either system you use will be at least 1/2″ thick. If you are not doing the complete room, make sure that you install some type of transition piece where the carpet or puzzle mat end.
Sealing Floor Penetrations
Whether you own your home, or you are renting, sealing the holes made for plumbing, heating, and electrical penetrations will add to the comfort and quiet of your home. Even small holes will carry airborne sound between floors and rooms. Typically all penetrations cut into the floor are larger than strictly necessary. (For example: A plumber will drill a 2″ hole for a 1 1/2″ pipe. He will not seal it once the pipe is installed.)
Caulk around all floor and wall penetrations. Many of those pipes travel through other rooms or suites in the building and if there is a hole on your side, there will be a hole on the other side. If the opening is too large for caulking alone, it can be filled with packing rod (M-D Building Products 71464 Backer Rod) first as backing to hold your sealant in place. Pumping a tube of caulking into a hole without sealing it tends to be depressing.
Buy a good quality caulking with excellent adhesion and elasticity. Copper, Pex, and ABS pipes expand and contract as they heat and cool. Good caulking will allow for this without separating from either the pipe or floor material. (Spray foam insulation also does not readily accept expansion and contraction without separating from pipe or floor.)
Note: Never use latex caulking around plumbing pipes. If there is even a hint of moisture on them, it will not adhere to the pipe and you have wasted your time and money.
Types of Sealants
GE 5010 Silicone 2+ available from Amazon is a very good window and door sealant but can be used anywhere. It is 40% more flexible than regular silicone and will not discolor metals–which might be important if you have copper pipes or are caulking around chrome. Available in clear and 5 colors.
Elastomeric Polymer Caulking
Other options include Tremco 830 and Mulco Supra (my favorite but only available in Canada). Both will adhere to almost anything, expand and contract up to 1400% without losing their bond, come in a wide variety of colors, and can be painted. The downside, for anyone who has not done a lot of caulking, is that they skin over quickly so if you plan to smooth it out–do it quickly. (Note: Don’t spend money on a fancy tool. Just lick your finger and run it through the caulking. Works great for almost any caulking except acoustic and latex base.)
Spray Foam Insulation
If you prefer something with better soundproofing qualities you can use spray foam in a can. Most of it has a high STC rating. But be careful. It is best if you get a can with a gun that screws onto it. They allow you to adjust the flow rate. Because you are probably filling fairly small holes.
The cans with the screw-on plastic straw applicator are difficult to control and you may end up with a quart of expanding foam in your vanity. If you are not comfortable with this possibility, it is best to stick with caulking.
STC, IIC, Thickness and Density Information
STC (Sound Transmission Class) is a numeric value defining how well the floor (or building) works at reducing airborne noise. It is the most important value for wood and laminate floors.
IIC (Impact Insulation Class) is a numeric value defining how well the floor assembly works to reduce the effects of impact noise.
Thickness and Density of the soundproofing material usually impacts its ability to suppress sounds. Generally, thicker is better because of more mass. Thicker product may be a little more expensive but is well worth it. You do not want to be changing things next week if you are not satisfied.