Despite having concrete walls of a room, you are facing noise pollution which enters inside your room. Now you have a confusion: does concrete or plaster wall absorb or reflect sound?
You are also searching for a way to find a solution for fully soundproofing a room wall that is built with cement, sand, and broken stone. But now, you are not clear that is concrete soundproof or not?
I think you have come to the right place for knowing some notes about the soundproofing of hard walls.
At the same time, you will find the answer to this question: how to fully soundproof a concrete wall?
So continue reading. If you want to find the solution.
First, you should know the actual definition and soundproof ability of the concrete material/plaster.
What is Concrete Material and How to Make It
When there is a mixture of aggregate, cement powder, and water in an exact amount, then this combination is called concrete (composite material).
You may have a question about what is aggregate. It may be sand, rock, or gravel. You have understood that concrete or normal concrete (cementitious materials) is a mixture of sand, water, and cement.
Now, I will describe whether these mixtures are soundproof or not. After getting that information, you will be able to understand the soundproofing capability of this mixture.
Does Concrete Wall Absorb or Reflect Sound?
Stone is a great sound barrier. So limestone is also a sound barrier. Limestone is the main element of cement. So you can say that cement is also soundproof.
I want to tell you that plaster is also great soundproof because it is mixed with soundproof limestone and soundproof sand.
But here the actual question is that, has the concrete material acoustical absorption or reflection?
The surface of the brick wall is not plain like a mirror. Common concrete walls reflect sound but a little amount of sound (ambient noise) is absorbed in the concrete walls. (source)
The main reason is that the sound cannot pass through the cement mixture.
Concrete walls cannot allow airborne sound to pass. Because it is a great sound barrier. Some sound is also absorbed in the surface of hard plaster material because the noise reduction coefficient of smooth concrete is 0.00 – 0.20 and sound (acoustic) absorption coefﬁcient is 0.06-0.36. On the other hand, structure-borne or impact noise can flow or pass through this type of wall.
Is Reinforced Concrete Soundproof or Not?
First, you should know the difference between concrete and reinforced concrete. According to stress and strain, the modulus of elasticity of concrete(Ec) is also measured.
When steel (hard studs) is attached to concrete for growing more structural strength, then it is called reinforced concrete. It is used in heavy and large construction like bridges, building structures, etc.
On the other hand, when concrete is used in any wall without steel, then it is called normal concrete.
Now, I am coming to the point. Reinforced concrete is not fully soundproof. It can block only airborne noise. But structure-borne noise or impact noise can flow through it.
Are the Concrete Walls Soundproof?
You have known that reinforced concrete is not fully soundproof because of the impact noise. The same equation is in the concrete or plaster wall.
Impact noise can transfer through plaster walls. Because the main function of impact noise is that it flows through hard substances.
This type of wall coating is also a great hard substance. On the other hand, it can block airborne noise. So this wall coating is not also 100 percent soundproof.
Sound Transmission Through the Concrete Walls and Floors
Notice this image carefully and here you will see which type of sound can transfer through the wall.
Now, you need to stop the transmitted sound if you want to soundproof a concrete wall. For doing that, you should follow some easy guidelines.
Continue reading, if you want to soundproof your room wall, floor, and ceiling.
How to Soundproof Concrete Walls, Floor & Ceilings
Now, I am telling you how to soundproof your room which is built with plaster. For doing this, you need to read the points below carefully.
1. Filling the Cracks
You should fill the cracks or holes of a plaster wall and ceiling. Because any noise wave can pass through these cracks. For doing this, You can use reliable acoustic sealant to block those cracks.
2. Using MLV (Mass Loaded Vinyl)
MLV is a great sound barrier that you can attach to any surface where sound wants to pass. You may be able to reduce airborne and structure-borne noise by using the MLV.
Besides, you can use other acoustic plastic (material), if you want. If you have any confusion about acoustic plastic, you should read the article: does plastic absorb or reflect sound?
3. Using Drywall with Resilient Channel
You can add an extra layer to any surface of the plaster by using drywall. It will be better if you use the resilient channels to drywall and this setting is not hard work.
4. Using of Underlayment
Underlayment is also better among other noise barriers. You can also use it on the concrete floor or slab to stop the transmission of impact noise.
For example, the sound of footsteps may transfer through that floor. You can easily avoid this impact noise (frequency energy) if you use acoustic underlayment.
5. Using of Soundproof Blanket
You can use a noise-reducing blanket to the main door of a building. Some sound may pass through the door if the door has cracks. You can stop the sound by soundproofing a door and using an acoustic blanket to that door.
6. Using Acoustic Foam Panel (Porous Materials)
If you want to reduce the level of sound pressure, you can use acoustic-type foam (absorptive/ absorbent materials).
It has the design of a porous (air chamber) structure which has the ability of noise (sound) absorption and you can attach it to any surface by using spray adhesive. To free from echo (to build an anechoic chamber), you need to use acoustic materials.
These points are the basic requirements to reduce sound levels. If you are interested to know the full implementation of acoustic elements (acoustic insulations) in plaster surfaces, you can read the topics below.
Does Bass Noise Travel Through Concrete Material?
Bass is one kind of instrumental sound that can pass through plaster or concrete as impact noise. Through the vibration of plaster walls or floors, this type of sound energy can be transmitted by sound vibration.
The sound may also produce from mechanical vibration which you should reduce. You know that impact sound can pass through hard substances.
This is the reason why you need to set up acoustic accessories for your plaster surface. You should focus on sound transmission loss of your room floor, ceiling, and wall.
Before setting up any accessories, you should read the exact guideline for the exact acoustic element.
Best Concrete Blocks for Soundproofing a Wall
During wall construction, you can use concrete blocks in replacing brick. This block is created by mixing with cement, sand, or rock.
This is the reason why this type of hard block can stop maximum sound waves. Both the interior surface and the exterior surface of this wall have the capability to reduce maximum noise levels.
So this is a great advantage if you use this type of block in building a wall. It will be more good if you plaster the wall surface for better performance.
Overall, I want to tell you, plaster is not a fully soundproof element. You can also measure the sound insulation level of plaster walls by sound reduction index.
Here, I have tried to clear the insulation capability of plaster or granular materials so that you can easily understand this topic.
I have also shared the way to soundproof a plaster wall. Yes, you can apply acoustic elements to that wall for getting more insulation capability.
If you don’t understand the implementation process of acoustic accessories, you should read the guideline for applying any accessory.
FAQ: Does Concrete Reflect or Absorb Sound
What Is the Reflective Sound of the Walls?
Reflective sound is made during sound reflection. When any sound wave travels in a medium, strikes that wave to another surface bounces back (reverberation), and travels to another medium, then this type of bounce-back wave is called reflective sound.
Such as, airborne sound frequency is reflected and absorbed by the plaster wall.
Does Concrete Actually Dampen Sound?
Sound dampening means weakening the sound waves. So I want to tell you that, of course, concrete can weaken the audible sound.
In this article, I have described why plaster weakens any type of sound. If you read the total article, I think, you will get a clear concept of the plaster which dampens the offensive sounds.
Is Concrete Bad for Using Acoustic Accessories?
Plaster is not bad for acoustics accessories. You can apply acoustic (soundproofing) material to the plaster surface for the performance of acoustic absorption.
No sudden chemical reaction is happening in the concrete (solid) materials. This is the reason why acoustic materials don’t change their soundproofing (sound absorption) properties when you apply them to any plaster material.
Are Concrete Ceilings Soundproof or Not?
Normally it seems that the concrete ceiling can stop some sound. But actually, it is not fully insulated. There are many reasons.
I have also explained this topic in detail in this article. There are two types of noise. One is airborne noise and the other is structure-borne noise or impact noise.
Impact noise can flow to the plaster ceiling. This is the reason why you should focus on soundproofing a plaster ceiling.
How Does any Type of Concrete Wall Work to Reduce Sound?
You know that concrete is a mixture of rock, sand, and cement. These elements have a high weight.
You also know that any heavy rigid material can stop maximum sound waves. Plaster walls are also heavy rigid material.
This is the reason why this wall can reduce some unwanted noise waves instantly. Only structure-borne noise can pass through this rigid wall.
So I think you have got the point of what you wanted to know.