Concrete is a popular building material that’s widely used all over the world. It has come to be the top choice for both commercial and residential constructions, but does concrete possess noise reduction properties?
Traditionally, the strength, thickness, and durability of concrete constructions are presumed to possess soundproofing properties. But in actuality, concrete holds very little ability to block sound. Concrete is not a conductor of sound energy and lacks the structure needed for the absorption of sound waves.
The sound absorption coefficient of a concrete (plain cast) wall is 0.02, which means about 98% of the sound waves that hit the concrete wall get reflected back. This indicates how poor concrete is at soundproofing. However, you can always improve its noise-reducing properties with a few simple hacks.
Is Concrete Good For Soundproofing?
The answer to this question could be a yes or a no. Soundproofing means blocking all kinds of sound waves from entering your space. This involves airborne as well as impact noise.
So, can concrete block noise?
It depends on the kind of noise you’re trying to block. The thickness and density of a concrete structure work as a reasonably good sound barrier for airborne noise, but won’t do much for impact sounds.
Concrete comes from a mixture of water, cement, and aggregate. There are many types of concrete, each of them possessing varying soundproofing capabilities. A unit of material density of a 1/4th-inch concrete block is 140pcf to 175pcf. The air content in concrete ranges from 1% to 2%.
Air pockets help in absorbing sound waves, and since concrete has low levels of air content, sound energy can only pass through the surface in the form of vibrations. This is why normal concrete cannot provide insulation against severe weather conditions like freezing or thawing.
The absence of air cavities is the main reason why concrete performs poorly at blocking sound waves. It can block some of the airborne noise from entering the construction due to its hard, reflective surface that bounces a significant amount of waves hitting the surface from outside.
All in all, no, concrete alone is not good at soundproofing. You will need to add some more soundproof products to completely block noise.
How To Improve Noise Reduction Ability Of Concrete?
There are a couple of things that need to be set in a certain way for a wall, floor, or ceiling to be soundproof.
How can you soundproof concrete walls, floors, or ceilings? The answer to all these questions revolves around the density of the whole structure. The denser, heavier, and thicker a structure, the better it can absorb sound.
Here’s our brief take on ways to improve noise reductions in concrete constructions.
Add A Layer Of Drywall
The best and perhaps the cheapest way of soundproofing concrete or existing construction is to add a layer of drywall over it. You don’t have to tear away or re-do any part of the concrete wall.
A concrete wall lacks the mass that is required for the absorption of waves. Drywall levels up the amount of mass in concrete construction and will also increase its density. The best part about this soundproofing solution is that you can always add more layers and get the desired level of sound blocking.
Add Resilient Channels
This is an application of the decoupling technique which is based on separating two objects so as to eliminate all points of contact that can transmit sound waves.
You can use resilient channels or isolation clips for decoupling.
These are small channels that are attached to the studs on the wall with the help of screws. Drywall is added to these channels in a way that it makes no contact with the studs behind.
Drywall is only connected to resilient channels. If sound enters from outside and vibrates the concrete wall, the drywall will not be able to carry these vibrations inside since we’ve eliminated all contact areas.
Sound isolation clips sit on the studs themselves. Unlike resilient channels that are installed along the entire width of a single stud wall, isolation clips can dampen sound straight from the studs.
The isolation clips are covered with hat channels. This is where drywall is then attached with the help of screws. One of the most popular kinds of isolation clips is whisper clips. The idea, again, is to restrict the movement of sound waves through vibrations by dampening them.
Acoustic slabs are mostly a blend of high-density materials such as glass fiber, mineral wool, mineral fibers, and wool. You can add them during construction within walls for insulation against, heat, cold, and sound.
Acoustic slabs from recycled glass or wool also work as great fire-resistant. If you have space, you can add an acoustic slab covered in fabric onto the wall. They will add mass and more air pockets that will effectively trap sound waves.
Blanket insulation is another cost-effective way of improving the noise reduction ability of concrete. These blankets are specially manufactured with insulation materials. They come impregnated with silicon or synthetic material that absorbs sound as well as heat.
You can either add blanket insulation to your room as a temporary solution or a permanent one. You can either hang the blanket curtains to the wall for temporary usage or low soundproofing needs or attach them to the wall permanently.
Its flexible fibers come with an impressive R-value of 2.9 to 3.8 per inch of thickness. You can fit them between joists, beams, or studs if you choose to install them in a permanent manner.
You cannot leave all noise blocking to the thickness, durability, and strength of concrete construction. No matter how dense concrete is as a material, it doesn’t have sufficient air spaces that can trap sound inside and stun its transmission.
There are several methods of soundproofing concrete that use a combination of different kinds of materials. You can add them before, during, or after construction.