You’re probably here looking for the best way to soundproof between floors because your noisy neighbors can’t keep it to themselves. Or maybe you’re the one receiving complaints for being too loud?
Whatever the case may be, there are several effective ways you can use to deaden or dampen the noise that always finds a way through your floors. No matter what kind of floor you have, fundamentally, the best way to soundproof between floors is to reduce both airborne and impact noise simply by increasing insulation between them.
You’d need to attenuate airborne noise with dense, high-mass material. And for impact noises, a robust absorption system helps. All in all, a mixture of both kinds of insulation will block sound from passing through the floors.
However, there’s a lot more to finding the best soundproofing option for your floors. Let’s discuss.
Four Elements of Soundproofing
There are four elements of sound deadening floors and other hard surfaces. It is imperative to pay attention to them when trying to control noise transmission or quality in a room. They are:
Sound Absorption
Sound energy, in the form of waves, travels more easily through brick, cement, and metal compared to air. These elements conduct the energy from one floor to the next. The first step of blocking the transmission of sound waves is to absorb them midway.
The idea is to separate the flooring from the structure of the building to restrict vibrations in one place. In other words, you “decouple” the pathway for these vibrations and then absorb the rest.
This can be done by adding an absorptive material or an acoustic membrane as a sublayer that is free from screws or nails that go into the structure. Decoupling the framing of the wall and ceiling also makes a huge difference.
The thickness and density of this layer will impact the absorption directly. And the softer the material, the less the sound transmission. You can easily do it if you add heavy carpets, rugs, or installing padding under carpets and floorboards.
Additional acoustical underlayment is another great but somewhat expensive option to go for. You can also use simple fiberglass insulation, mineral wool, cellulose, and recycled cotton to sound between floors.
Sound Breaking
An important yet often overlooked contributor to noise coming from another floor (or your own) are the squeaks. Squeaky floors transpire as houses get old and fittings/structures get loose. They can come from gaps between subfloors and surface flooring or between the subfloor and the joists.
Ignoring squeaky floors will not only add to noise entering or exiting the space but will also affect the construction in the long run. The most effective way of eliminating squeaks from gaps between subfloor and joist is to pull them together with a 3-½-inch or 4-inch drywall screw angled at the point they meet. Controlling the leakage of sound will result in better soundproofing overall.
Adding Mass
This is all about making the walls heavy. Some common materials to add mass to walls, ceilings, and floors are plywood, drywall, cement board, and OSB.
Vibrations from sound energy move/vibrate the wall when they come into contact. When you make the wall heavy with dense coatings, it becomes difficult for the waves to move the wall. Simple as that, when the wall stops moving, it stops transmitting the vibration (sound) through to the next floor. The wall will still vibrate, but very subtly and not that easily.
Drywall is one of the most effective, cheap, and widely used sources of mass. However, you’ll still hear low-frequency sounds even after adding mass. Use 5/8″ drywalls for best results. Although decoupling, sound absorption, and mass have dedicated jobs for controlling and containing sound, you still need a little more of it to eliminate all vibrations.
Sound Damping
Damping means dissipating the vibrational energy of sound waves before they get a chance to build up and fan out. It essentially targets resonance in a room and includes diffusion and reflection of sound. This is the last element of soundproofing.
There are plenty of materials used to damp walls, such as plasterboard or drywall panels that enclose damping compounds in between them. When sound hits the drywall, the forces between the panels create friction in the damping layer, and in the essence of thermal conversion, the sound ceases and converts to heat.
The highest performing amongst all is Green Glue. You can use it between standard plywood, drywall, or subflooring. It effectively dampens a high amount of vibration and helps in soundproofing.
Types of Noise Travelling Between Floors
Before you decide what the best way of soundproofing between floors is, you need to figure out the types and sources of noises in your room. To successfully soundproof your floor, you need to point out the kind of noise that is causing a disturbance and fix it accordingly.
There are two main types of noise that travel between floors:
Airborne or Ariel Noise
Airborne noise is the most common type of noise you hear. This includes the TV, radio, background chatter, alarm tone, dogs barking, cars, horns, and music from the surroundings. Ariel noise is transmitted by air and travels linearly until it hits a hard surface, such as floor, walls, or ceiling, to bounce off.
Airborne sound waves bounce and reflect off of such surfaces until they are absorbed and/or transformed into another form of energy.
However, only absorption will not reduce noise! For this, you must use acoustic insulation (preferably around 100mm) between the floor joists. Airborne noise can travel through small openings in the wall, windows, ceilings, this proper soundproofing of the floor is necessary to contain it.
Impact or Collision Noise
These sounds are generated from objects. When two objects collide together, they produce vibrations (noise). Impact noise is also called footfall noise, and as the name suggests, this noise is produced from impacts such as footsteps, furniture, jumps, or when you drop something on the floor.
Impact noise travels through air and the ceiling under, this means impact noise affects the floor below you more than any other area. It is harder to soundproof against. It is because such noise is caused as a result of direct contact with the surface.
To soundproof against impact noise, you’d need to make the floor as soft as possible. Soft surfaces such as carpet or wooden floors conduct less energy and thus are better at soundproofing. Installing a sublayer of acoustic insulation also helps.
Things to Consider When Soundproofing Between Floors
Here are a few considerations you must take care of before you figure out the best way to soundproof between two floors. Ask yourself the following questions:
Are you soundproofing to keep noise in or out of your space?
This affects the placement of soundproofing solutions. For instance, if you’re trying to keep noise from your loud upstairs neighbors away, you’d need to treat the ceiling a little more than the other areas of your space.
Similarly, if you don’t want noise from your property to travel down to the floor below, you’d need to work more on the floor, its layers, and sublayers.
What type of noise is bothering you?
This section has already been discussed earlier. Here’s the gist of it; you tackle airborne sound with absorption. And to handle impact noise, softer surfaces are used to reduce the impact of two colliding surfaces.
What kind of floors do you have?
Timber joisted floors and concrete floors are the two common types of floor construction. Timber joisted floorboards need carpets and concrete (solid 6”) floor needs an acoustic layer (discussed later) over it.
How loud is the noise?
Soundproofing requirements are different for different levels of noise. For example, muffled conversations and other low-level noises need lesser soundproofing as compared to loud level noises.
Just like that, impact-only sounds need more soundproofing than only airborne noise. Hence, the loudness of noise defines the kind of material, insulation, and the areas of soundproofing.
Can furniture/décor change help your case?
Quite interestingly, sometimes, furniture can reduce impact noise with very notable results. This is because furniture tends to absorb vibrations from impact noise. So, when you move more furniture to a room that has been affected with impact noise, you’ll notice a clear difference!
Adding more wall hangings or canvases along with furniture with cushions or soft surfaces will help in the absorption and decaying of sound. Thus, if the noise level is low, you can easily combat it with little tweaks to the room.
Type of Floor You’re Soundproofing?
As the two types of noise affect the ways of soundproofing your space, the types of floor constructions also have an impact. There are two types of floor constructions, the details are as follows:
Timber Floorboard
The best way to soundproof timber floors is with a thick and heavy carpet. Most of the sound that travels below is impact noise, and the ideal way to deal with it is the use of carpets that can reduce/soften the impact.
Carpets and rugs absorb vibrations, and you can enhance it if you add drywall between the carpet and the floor. You can also use acoustic underlay mats or floating floors.
Concrete Floors
Concrete floors are thick with a lot of mass and density. This means airborne sound cannot easily pass through it, but impact noise will transfer through the concrete floor.
A resilient layer of impact-absorbing material over the concrete floor will reduce the transfer of the impact. You can also use floating floors to isolate the concrete sub-floor from the finished floor. A 5mm mat made from rubber granules or fibers is ideal!
Soundproofing/Insulation Products
There may be many soundproofing options today in the market, but only some of them are effective at toning down the noise. Here are the best ones you can find:
Polyethylene Foam
Polyethylene foam is suitable for new constructions. It involves laying a smooth, predictable, and even surface for new flooring installations. On top of the subfloor comes the flooring underlayment and then the final floor is installed.
The thinnest polyethylene foam underlayment is only 2mm thick and is perfect for low noise levels. The closed-cell foam is easily available at very affordable rates. It isn’t considered as effective compared to the following options but can provide considerable insulation.
Acoustic Foam
This is an expensive version of the simple, straightforward foam underlayment. Acoustic foams are usually 3mm thick and fairly dense at around 20 pounds of sound-absorbing material per cubic foot.
Acoustic foam underlayment is laid the same way as other foam underpayments. They are designed to deaden and dampen sound vibrations and decay them before they can reach the wall below. The denser your acoustic foam is, the better the insulation.
Plywood Underlayment
This kind of underlayment is usually used under flexible and relatively thin floors. Such floors are made of materials such as linoleum or vinyl. Just like that, plywood is another effective soundproofing material.
Sometimes, to minimize floorboard squeaks, red rosin paper or tar paper is laid on top of the plywood floor. This kind of underlayment is moderately effective but won’t block all of the noise.
Felt Underlayment
Felt underlayment is an effective choice for noise reduction. It’s somewhat an expensive choice but offers excellent sound absorption.
Recycled felt underlayment is an eco-friendly option to go for. It is around four times heavier and twice the price of polyethylene foam. This is your best bet if you have laminate or engineered wood floors.
Acoustic Underlayment
Special acoustical underlayment on the subfloors is usually over 1-inch in thickness and may sometimes cause uneven floor levels in adjacent rooms.
Acoustic underlayment differs from foam and plywood because it elevates flooring to create a dead air zone. This zone helps in trapping and reducing vibrations from transmitting to the next floor. Other than that, it is an excellent option for soundproofing floors.
Cement Board
Cement is dense and heavy, properties perfect for sound blocking or soundproofing. Hence, using cement boards as tiles or bases on the floor will offer better sound insulation than wood.
Conclusion
The best way to soundproof between your floors depends on figuring out these two things:
- The kind of floors you have.
- The right soundproofing solution for that floor kind so that both impact and airborne noise are reduced.
You’d need to add a combination of sound-absorbing, mass-loaded, and sound dampening materials in between floors to completely block noise.
Moreover, factors like the intensity of noise, amount of furniture, or the type of noise also need due consideration. You can choose either acoustic foam, plywood, felt, or cement underlayment for the best results.