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One goal of everyone in their homes is to live and go about doing what they do without having to deal with some nerve-racking noise.
In many homes, the transfer of sounds from room to room is a predominant issue that many want a solution to.
Over the years, concrete has come to be one of the most popular building materials in the world. It is a top choice for both residential and commercial constructions.
Conventionally, concrete is presumed to automatically have good soundproofing properties because of its thickness, strength, durability, and other unique qualities.
But the truth is; concrete is not as good at soundproofing like many think it to be. The question remains; ‘why?’ Because concrete is a very good conductor of sound.
I’ll explain that. Even though concrete is thick and versatile, the principles behind the propagation of sound cancels out its chances of becoming a good sound dampening or blocking building material.
How Is Sound Produced?
Sound is given off in form of energy and it requires a continuous medium for it to keep traveling. This implies sound is transferred from its source to other places (mostly our ears as the last stop) through a medium. This medium could be anything except a vacuum –could be air or a solid material.
The air is the largest medium through which sound travels. The constituents and mass of air are in a way that the particles are close but loose. Therefore, when sound is produced, the waves vibrate the first particle(s) it comes in contact with, and it will go on vibrating other particles until the sound hits an ear or the wave length is reduced.
In the same way, sound waves travel through solid materials by vibrating the molecules that constitute the solids.
Read this article for a more detailed explanation.
How Soundproof Is Concrete?
Just like I mentioned above, concrete may have such qualities as thickness, sturdiness and durability that many may automatically believe it makes a good sound block. However, this is far from the truth.
Thickness alone doesn’t qualify a material to provide the level of noise reduction most homeowners want. In most constructions, concrete walls are cast without any cavity in them and this is what reduces their soundproofing capabilities.
Since many general contractors rarely bear the sanctity of the inner building in mind during construction, they build the normal thing –walls that allow noise to seep through easily. And this will require you to spend more than you would have at the initial stage on keeping sounds in or out of a room.
If you have noticed, walking on a concrete floor or knocking on a concrete wall produces an audible sound. This sound is as a result of impact on the floor or wall, and the rigidness of concrete.
The trick in making concrete soundproof is to leave air gaps within the walls to trap noise. But this can only be achieved in homes that are still under construction.
You are probably asking ‘So my already built apartment/home can’t be soundproofed?’
Of course, it can be.
If your home or business suffers from distractions caused by noise from concrete walls, following a couple of steps carefully will help you achieve the quietness you desire.
In this post, I will walk your through the most efficient methods for quieting concrete walls.
Practical Methods Of Soundproofing Concrete Walls
A couple of things need to be in place for a wall to be totally noiseless. While there are many ways you can go about quieting your concrete walls, they all revolve around ‘playing’ around the density of the structure. This is true because higher density allows for better sound absorption.
Let’s have a brief overview of the practical methods of soundproofing concrete walls.
1. Add A Layer Of Drywall
Fitting a layer of drywall on the already existing wall can go a long way in achieving a noiseless living. The idea is cost effective because you don’t have to pull your existing wall down.
A drywall will shoot up the mass of the concrete and this means increased density and increased absorption. However, you might notice only a slight decrease in sound transmission.
Other methods will complement the effect to help you achieve your goal of living in a noiseless, conducive environment.
2. Decouple The Walls
Sound waves need a continuous medium for traveling and concrete provides that as they are joined to other walls, and other noise entryways like doors and windows, to keep the sound going.
Decoupling comes in to create an air chamber or gap between walls. The method requires you to build walls with spaces within which air can trap noise and prevent the sound from vibrating the other side of the wall.
Allow me to explain this better. A decoupled wall receives sound waves and breaks the wavelength. The surviving waves are then trapped in the air chamber just before they hit the other part of the wall.
The cavity between the decoupled walls can also contain loose insulation but care should be taken not to stuff up the whole space in the process. This is because the aim of decoupling will be lost if an air chamber is missing.
Decoupling can be approached in many ways which I will outline shortly. One thing these methods have in common is they eliminated surface contact and introduce an air cavity to attenuate any sound that gets into the cavity.
- Room within a room
A room within a room construction, perhaps, the most popular and effective approach to decoupling walls. To build a room within a room, you erect two walls that are totally detached from each other.
The gap between the surfaces of these walls (stud layers) becomes the air cavity. The absence of a physical connection between the walls ward off the transfer of sound coming from the internal or external wall.
Read this article from soundproofing company for a better understanding.
- Double stud wall
The double stud wall is an easy, cheap alternative to the room within room method. Here, the set of studs are attached to the same base plate. To finish up, fit drywall to the outer sides and use loose insulation in the cavity.
- The staggered stud wall
This is another alternative to the room within room setup that is more economical and space efficient. In the staggered wall setup, a 2×4 set of studs is arranged on either side of a base plate, preferably six inch wide. Having the studs this wide creates a large air cavity to achieve the aim of decoupling.
After decoupling with any of the methods above, loose insulation is placed in between the studs to absorb any sound that makes it into the cavity.
In some situations, low frequencies can escape these insulators (I’ll show you how to go against this). But on the bright side, high frequencies are kept in check.
Read my article comparing the staggered stud wall and double wall constructions to know more.
Even with all these methods in place, some sounds will still resonate a decoupled and properly insulated concrete wall.
Resonance occurs when a sound finds the right frequency to vibrate every component of the wall. If your wall is well insulated, you don’t have to worry about high frequency sounds resonating it. But it is definitely a messy situation when you have to deal with low frequencies, probably from your subwoofer.
There are two ways to lower the resonant frequency of a concrete wall:
- Boost the wall’s mass
Having plenty of mass on each side of the wall makes it tougher to vibrate and gives it more sound absorbent features. Remember more mass equals increased density.
For better results, you can add more insulation but remember to allow plenty of air in the cavity for absorption. Doing this will push the resonance point so low that only the deepest frequencies will escape.
- Using soundproofed compounds
Another way you can lower the resonating frequency of a wall involves the use of soundproofing compounds and acoustic sealants.
Think of this process as making a sandwich. First, you pad the wall with a layer of dry wall. Then application of the noise-proofing compounds on the drywall will follow. A layer of drywall will be fixed after treating the wall with these compounds and sealants.
4. Resilient Channels And Sound Isolation Clips
Until now, we probably know decoupling as a method requiring at least two walls. There are ways of decoupling a single wall with the use of resilient channels and sound isolation clips.
- Resilient channels
Resilient channels are metal channels that are screwed to the studs. The drywall is the installed in a way that it is only connected to the resilient channel and makes no contact with the studs.
- Sound isolation clips
Instead of installing a resilient channel to span the entire width of the single stud wall, clips can be placed on studs to dampen sounds.
Hat channels are placed in the sound isolation clips. Then, drywall is attached to the channel with screws in a way that contact with the studs is avoided.
A popular example of sound isolation clips is the whisper clips. They have a special mechanism for dampening sounds that vibrate the hat channel.
Read my detailed article on soundproofing clips and resilient channel.
Final Thoughts On Soundproofing Concrete Walls
Conducive living is what every homeowner expects from their home and so, any form of disturbance will have negative effects. Chances are you won’t study or rest properly in a room when you can hear everything going on in the adjoining room.
Quieting concrete walls doesn’t have to be difficult. If you follow these steps carefully, you will definitely find one that will suit your needs.
Lastly, in some cases, soundproofing just the concrete walls in your home won’t be enough to keep rattling sounds out of earshot. Consider soundproofing your doors and windows also to achieve optimum results.
Thanks for reading! Before you go, check out my recommended products for soundproofing.