Insulation and Soundproofing (Don’t Pick the Wrong One)
Acoustic insulation and soundproofing are not the same thing but people use these terms interchangeably. Soundproofing, (sound insulation) means that sound is blocked and cannot pass from one side of a material through to the other. Acoustic insulation is a specific material that does not block sound and is, therefore, not a soundproofing solution by itself.
However, absorption is one of three core ingredients that create the perfect soundproofing recipe. Alone, these three ingredients cannot soundproof something, but together, they can.
Absorption prevents the drum effect in cavities of walls, floors and ceilings. The drum effect is when sound reverberates (echos), inside a space which is heard as an amplification. It is an issue that soundproofing fixes.
High-mass materials are able to resist airborne noises, like talking and music. These sounds are reflected away so they are unable to enter or leave a space. High materials are essential in soundproofing.
Decoupling, or isolating, refers to ‘pulling apart’ two surfaces. This reduces the vibrations able to travel through one material directly into the next. It is the best soundproofing technique for space used.
To create good soundproofing, all three of these techniques need to be used together.
What is acoustic insulation?
It’s not what you think it is!
Acoustic insulation is a material that looks like normal wall insulation. However, it is not! To be considered acoustic, it needs a mass of 45kg/m2 or more, (so it has a high mass). Standard cavity insulation for lofts and walls is made for thermal insulation. It therefore does not have the same high mass as acoustic mineral wool so it won’t noticeably improve your wall soundproofing.
What is sound insulation? Don’t get confused!
You may associate the word insulation with thermal solutions and soft materials. However, to insulate means to prevent something from spreading.
To prevent sound from spreading, we need to use high-mass, heavy materials. For a sound wave to pass through a material, it needs to be able to continue to vibrate (wiggle up and down!). If the material doesn’t allow for this movement, it will be reflected off instead. This is sound insulation.
More mass makes for better sound insulation – here’s why
The more mass a material has, the harder it is for a sound to move through it. This makes sense, think about pushing a piece of paper; it moves easily. Now push a brick, is that going to move as easily? Nope! Sound has the same issue; it needs more energy, or force, to move through heavier materials, like bricks, than lighter materials like fabric, (yes, soundproofing curtains are a myth).
So, while ‘acoustic insulation’ refers to a specific material, (mineral wool insulation with a high mass), the term sound insulation refers to the process of preventing sound spreading.
How you can stop the drum effect
Acoustic insulation is used to absorb noise in cavity spaces, this is done to control the drum effect. The drum effect is an amplification of a sound because it is trapped in a cavity space. The trapped noise energy reverberates from surface to surface, causing noises to be repeated.
To prevent the drum effect, and noise getting louder, we fill the cavity spaces with acoustic mineral wool. Noise can enter the open structure of the mineral wool which stops it from bouncing from wall to wall. As the noise travels through the mineral wool, it loses energy and the noise is controlled.
How to use insulation to soundproof a room
Insulation must be used in cavity spaces to help soundproof a room and reduce the drum effect. The drum effect happens in open cavity spaces and will amplify your noise issue so it must be controlled.
You need to use acoustic insulation with a mass of 45kg m2 or more to ensure that it has acoustic properties. Standard wall and loft insulation is not made with acoustic properties and will not give you a reduction in your noise issue.
Where to use acoustic insulation
- Between stud work in walls
- Between joists in floors
- Between joists in ceilings
The best wall soundproofing with acoustic insulation
The best wall soundproofing, with acoustic insulation, is the MuteClip system. This system uses all three core soundproofing elements (mass, absorption and decoupling), and works on brick and stud walls. It gives you sound insulation, sound isolation and sound absorption.
The MuteClip decouples, or isolates, the existing wall from the new soundproofing panels to give you the best soundproofing for space used. Behind the MuteClip channels, we install acoustic mineral wool to prevent the drum effect. To finish all of this, one or more layers of soundproofing panels are screwed into the channels.
Acoustic insulation creates sound isolation – why you should care
Using acoustic insulation will isolate sounds and this reduces the transference of noise between materials. We use a MuteClip system to create a physical separation between materials, and this isolates noise.
Acoustic mineral wool is considered to have sound isolation properties because materials it is in contact with cannot easily pass vibrations beyond the mineral wool. Instead, noise is trapped inside and doesn’t pass the vibration energy along to the next layer.
What is the best acoustic insulation?
The best acoustic insulation has a high mass, we recommend 60kg/m3 or more. To be considered acoustic, mineral wool needs a mass of 45kgm3 or more, but for the best results, get a higher mass! We go all the way up to 100kgm3!
In terms of brands, we use the two trusted neds of Rockwool and Knauf for our acoustic mineral wool.
Is acoustic insulation easy to install?
Yes, acoustic insulation is easy to install on walls, floors, and ceilings. It comes in bales which contain individual slabs. The slabs fit between joists and studs snuggly and are easy to press into place.
Acoustic insulation can be cut to fit your unique space. PPE like glasses, gloves and masks should be worn as this is a fibrous material.
Can I use normal insulation instead of acoustic insulation?
No, you can’t use ordinary insulation instead of acoustic mineral wool insulation. Ordinary insulation is made to be thermal and doesn’t need to have a high mass of 45kgm3 or more. Without this high mass, the insulation cannot create a noise reduction.
Do I need to use acoustic insulation to soundproof my room?
Yes, acoustic mineral wool needs to be installed into cavities to help soundproof a room. Without using acoustic mineral wool, your room will suffer from the drum effect which is when sound is amplified in cavity spaces. The nose reverberates inside a cavity and creates a buzzing amplified version of the original sound.
To soundproof a room, acoustic mineral wool should be used in wall cavities and floor/ceiling cavities alongside materials of high mass and, ideally, a decoupling solution.
How thick is acoustic insulation?
We have acoustic insulation in 100mm, 75mm, 50mm and 25mm thicknesses. Acoustic insulation comes in different thicknesses to suit the depth of your wall, floor or ceiling.
