How To Soundproof a Garage or Bar
Introduction to Soundproofing
This article tells you how to soundproof a garage, bar, studio, or any other room. Soundproofing is when steps are taken to reduce sound entering or exiting a building by using insulating and isolating materials. A garage for example would have very poor acoustic insulation value. If you will be making a lot of noise in your garage (such as using it as a bar or drum room), you may irritate your neighbours if soundproofing is not carried out. The most challenging part when it comes to soundproofing is dealing with doors and windows, as they are classed as acoustic weak points. Other weak spots include socket outlets, light fittings and ducting.
Soundproofing is usually carried out for two reasons:
- To stop sound escaping a room and disturbing your neighbours.
- Soundproof a building or room to stop noise getting in, such as a recording studio.
It is important to note that soundproofing techniques allow a reduction in sound transfer through a building, but cannot completely stop sound. Read the next section to fully understand why this is.
What is Sound?
To understand why sound cannot be completely blocked is to know the science of sound. The best way to visualise sound is to compare it to water, like ripples on a pond. Sound is simply the vibration of particles through a medium such as air or a material. A sound wave propagates through the air via a chain reaction, passing along its vibration from one air particle the next, even carrying on through materials such as brick. We only hear sound once it reaches our ear drums, vibrating receptors that our brain interprets as sound. Different frequencies of vibration are picked up as different sounds.
What can help Block Sound?
It is more difficult for soundwaves to travel through a material, rather than air. Mass is a term used to define the amount of material an object has. More mass equals more soundblocking properties.
Sound waves decrease with distance. Sound decreases 6 dB every time the distance is doubled, which is a good general rule of thumb to go by. The decrease in sound due to distance can actually be calculated using the Inverse Square Law.
Previously we talked about sound being a vibration that passes through air and materials like a ripple in a pond. Decoupling is probably the hardest thing to implement when learning how to soundproof a garage or bar. It is a soundproofing method used where sound vibrations are separated between different parts of a building. The aim of decoupling is to reduce noise transfer by separating materials, so that it is more difficult for vibrations to be directly transferred from one to another.
After your hard work soundproofing a building, you may be surprised to now find you are getting echos when speaking or playing music. Echos occur when sound waves cannot vibrate through objects easily, and tend to bounce of surfaces instead. Echos are worst in rooms that are bare, and full of hard flat surfaces. You may be wondering why echo’s are a problem? Well, if you have a room full of people trying to talk, then the echo’s will make conversations less easy to understand. Because of this distortion in sound, people tend to speak louder or turn music up in order to hear it more clearly. Reducing echos means you can then reduce the volume, which further helps noise pollution in your neighbourhood. You can reduce echos by absorbing some of the sound (or changing its path) with fabrics. For example, you could fill your room with rugs, sofa’s, blinds, curtains, etc.
How to Soundproof a Garage or Bar. Step by Step
Learning how to soundproof a garage is actually a complicated task, there are so many things to consider. The step by step guide below tells you how to soundproof a stand-alone garage with a single skin breeze block wall. This guide tells you how to insulate your garage to a reasonable standard, without costing an absolute fortune. Much higher levels of soundproofing can be achieved with additional techniques, but would cost much more. You can view a video at the end of this article to hear the difference for yourself. Only you can decide how over the top you need to go with the soundproofing.
1. Install a Pitched Tiled Roof
A tiled pitched roof would have better acoustic insulation properties over felt roofs. This is becuase the sound is forced to travel through more mass. Also, pitched roofs on garages are generally a good ideas anyway as they are reliable, more robust and look much nicer.
Below are images of a garage flat roof being replaced with a composite tiled roof.
2. Install a Composite Front Door
Garage doors are usually made of metal, which is an excellent sound conductor. Ideally you want to swap your garage door for a PVC door, or a composite door is you can afford it. Remember that your doors and windows will be the weakest acoustic point. Do your research and buy a door with the best acoustic properties. A decent garage door will also help thermally insulate the building too.
3. Consider your Windows
Ideally you should consider having no windows if you want to achieve very good sound insulation. If light through windows is desired, then ensure they are triple glazed to give you the best acoustic insulation properties. You can even buy special acoustic grade glass which usually comes in a laminate form.
4. Build an Internal Stud Wall
A stud wall is basically a frame of timber designed to hold plasterboard, enabling an interior wall to be built. Usually stud walls are fixed to the wall behind it, ensuring there is a gap in between.
The example stud wall for this garage below has a gap of approximately 25mm between the outside and stud wall. You may notice that this stud wall is screwed to the ceiling and floor only. Doing this helps to reduce sound vibrations being passed on from one wall to another.
5. Install Rockwool Insulation
One of the best types of insulation used for soundproofing is called mineral wool, because it is formed from rock materials giving them a lot of sound blocking mass. Typically, a special soundproofing mineral wool is used, such as this RWA45 Rockwool insulation from the Amazon store. This particular Rockwool is much denser than standard Rockwool used to thermally insulate a home. The 45 tells us the density of this Rockwool slab, which is 45Kg per m3.
Rockwool slabs are manufactured in a variety of thicknesses and densities to suit most requirements. We decided to use a really dense Rockwool slab that is approximately 100Kg per m3 called Rockwool Duo. This is an interesting Rockwool because it has a dual density, with one surface denser than the other.
In our experience, we have found that Rockwool thickness is more important than density. Also, Rockwool tends to block out low frequency’s more than high ones. To help block out the higher frequencies too, you will need to also install acoustic grade plasterboard.
Below is a Video of the Rockwool Stage Completed
6. Sealing the Gaps within your Insulation
You will be surprised how sound can get through the smallest of gaps. Sometimes it is best to visualise sound as water, if water could esacpe easily, then so could sound. Make sure you fill gaps within your insulation with expanding foam. Do not get expanding foam on any PIR insulation or electrical cables as it can react over time. Gaps within PIR insulation such as celotex can be sealed via aluminium foil tape.
We recommend a good thermal and acoustic expanding foam, such as the one below:
7. Install Acoustic Grade Plasterboard
There is plasterboard designed for soundblocking purposes. Simular to normal plasterboard, it is much denser and therefore more effective at blocking sound. Be careful when installing these, they are a lot heavier than standard plasterboard! Make sure your structure can take the weight. The example below shows a combination of 12.5mm and 15mm thick soundblocking plasterboards. Details of this plasterboard are below:
Ceiling Plasterboard = Knauf 15mm Soundshield Plus
Wall Plasterboard = Knauf 12.5mm Sounds Panel (simular to this acoustic grade plasterboard on the Amazon store)
Plasterboard used for recessed areas (TV, drinks shelves, etc) = Knauf 15mm Soundshield Plus
8. Sealing the Gaps within your Plasterboard
We recommend you seal gaps between your plasterboard sheet using a good quality acoustic expanding foam.
Sound Test Example
We have put together a video which shows you the effectiveness of acoustic Rockwool insulation, and acoustic grade plasterboard. Hopefully this video will give you a good idea of what you require when learning how to soundproof a garage or bar. We have also tried to measure the dB of each stage, which we have put into a table near the end of the page.
Speaker used in the Video
The sound device used in the video is a Dove Bluetooth Speaker (Model number BTS-06). It has a distance range 10 meters, and a frequency range of 2.402 – 2.48GHz. Maximum output of this speaker is 2W, or 3.58dBM (RF max). There were no power outlet sockets when starting the project, which is why we opted for a battery powered speaker.
Song used in the Video
Unfortunately we could not use a popular song in the video due to property rights issues. Instead we downloaded a royalty free song that we could freely use on the internet. The tune is called “forest rythem” from a website called Audio Nautix.
Method Used to Capture the Video
- Placed battery powered Dove speaker near centre of the garage.
- Played the forest rythem song through the Dove speaker via a Samsung Galaxy A5 mobile phone on full volume.
- The sound playing through the speaker was video recorded via a normal handheld camera, with the door closed, and the door open. We also noted down decibel measurements for each stage.
- Hopefully this video will help you learn how to soundproof a garage or bar.
Decibel Sound Measurements
We measured the sound using an iPad application called dB Meter. There are obviously specialist devices out there for measuring decibels. But we wanted to use something that the average DIYer can get hold off for free. Please note, we were unable to put as much time as we wanted into the decibel measurements, as we done this job for a customer. We had a tight deadline to meet. But I hope you find the information we collected useful.
|Music||Door||Measure Location||STAGE 1|
After Acoustic Insulation
After Acoustic Insulation, Plasterboard ,Caulk
|OFF||Closed||Background Noise Inside||29db||26db||23db|
|OFF||Closed||Background Noise Outside||35db||35db||35db|
|ON||Closed||Side of Building||47db||40db||35db|
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