Sound Proof Insulation: Our Full Range

Noise pollution can be a major issue in modern homes, offices, and commercial buildings. This can harm your quality of life, your ability to work, or your ability to conduct business. A great option is to install sound proof insulation within your walls, floors, or loft. In this guide from Building Materials Nationwide, we’ll look through the types of sound passing into buildings, the types of sound proof insulation available, and the places within a building that could benefit from sound insulation. We’ll also have a quick look at your options for windows and doors, which cannot be traditionally insulated but can be altered to prevent noise leakage.

What Types of Sound Are You Hearing?

Sounds within your building will be split into two main categories, airborne sound and impact sound. Airborne sound moves through the air. This could be sound from conversations, TVs, or radios passing between floors. It could also be traffic noise on the street, or planes passing overhead. Impact sounds are noises caused by something being struck. This could be someone hitting a wall, or something dropping on the floor.

Flanking sound is used to describe sound waves that travel indirectly between spaces. Sound Waves can pass through cracks in walls, voids within walls, or gaps between insulation. Flanking sounds can be difficult to stop, especially in older buildings.

What is Sound Proof Insulation?

Sound proof insulation, now often called acoustic insulation, tends to work in two ways. They either work to absorb sound echoes within a room, or they work to block sound transmission. Some products offer both of these and some offer just one. These can be used throughout a wide variety of buildings. You could use sound proof insulation to block outdoor noise, such as busy roads in the city centre. But you could also use it to reduce noise passage within a building, such as loud conversations in a block of flats.

The reason acoustic insulation is often used as a term rather than sound proof insulation is that in most cases this insulation will not fully soundproof a room or property, merely reducing sound passage. Sound proof insulation can therefore offer tremendous benefits, and be downright essential in certain buildings, but it will not create a perfect vacuum. The levels of soundproofing needed for something like a recording studio are not needed to return your home or building to a livable noise level.

What Is The Best Sound Proof Insulation Material?

When it comes to finding the best sound proof insulation materials, it can really depend on which part of your building needs soundproofing, and whether you are looking to absorb internal sound or block external sound. Here are the most common types of sound proof insulation, and their relative effectiveness at stopping unwanted noise:

Mineral Wool Insulation

Offering both thermal and acoustic insulation, mineral wool rolls, batts, and rigid boards can be installed between joists or studs, offering quality sound absorption. Examples of mineral wool sound proof insulation would be the Rockwool Flexi Acoustic Slab, the Earthwool Acoustic Floor Slab, and Knauf Earthwool FrameTherm rolls. If you are looking to stop sound from escaping a room, mineral wool insulation will effectively absorb both airborne and impact noise. 

Glass Mineral Wool Insulation

Also possessing both thermal and acoustic insulation properties, glass mineral wool, or fibreglass, can be used as an insulation material. Glass mineral wool sound proof insulation will not be as effective as other mineral wools, but will offer a reduction in sound between floors and walls. An example would be the Knauf APR Acoustic Partition Roll Insulation. A disadvantage of glass mineral wool insulation batts is that over time they can slump in a wall, allowing flanking sound to pass through the gaps.

Blown Cellulose Insulation

Blown cellulose is a combination of recycled paper fibres and fire-retardant material, which is blown into ceiling and wall cavities. It is used for both thermal and acoustic insulation, filling gaps to provide stronger sound proof insulation than something like glass mineral wool. Disadvantages can be the cost of insulation, as you’ll need to hire someone with specialist equipment to fit it, and the dangers of dampness. If water comes into contact with blown cellulose insulation it can completely ruin it, requiring replacement.

Polyurethane Insulation Foam

Polyurethane insulation foam must also be installed by a professional, coming in open-cell or closed-cell design. It will be sprayed into cavities or onto wall surfaces, expanding and solidifying. Closed-cell polyurethane spray foam expands up to 50 times its original size, making it impermeable to moisture and vapour. Open-cell polyurethane insulation foam expands to 150 times its original size, making it a solid block against airflow. While polyurethane does offer sound proofing, it is not as effective as mineral wool or glass mineral wool, with sound waves passing through the solid surface formed, and the strong connection between the insulation and the wooden joists allowing vibrations to travel.

Sound Proof Insulation Mats

Produced from rubber or vinyl, sound proof insulation mats are thin rolls designed specifically to offer acoustic insulation. These are most often used as underfloor matting, usable over concrete or wooden floors. They can be used between floors in apartment buildings or multi-floor offices. Some good examples of insulation mats would be the IsoRubber base which offers high performance acoustic insulation, or the iKoustic MuteMat range.

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Acoustic Panels

An easy-to-install option, acoustic wall panels are simply hung over a wall, offering sound absorption within rooms. While their design makes them more suited to large communal spaces than homes, these panels will help to reduce noise within a room, absorbing sound waves. The main disadvantages are aesthetic, acoustic panels will be visible within your room and may not blend with the decor. We have a wide range of acoustic panels from Soundsorba available through our website, offering great acoustic results in a business setting.

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Where to Use Sound Proof Insulation Within a Building

Different areas of a building will have different needs in terms of reducing noise problems, and different possibilities in terms of sound proof insulation that can be installed within or on them.

The Best Sound Proof Insulation to Use in an Inner Wall

An internal stud wall would be best insulated using mineral wool products, to inhibit the passage of noise between rooms, which can be vital in shared housing. Mineral wool is affordable, easy to install, and offers a strong level of sound proof insulation. If your internal walls are solid, it is possible to construct a stud wall against them, which you can then insulate and face with plasterboard. We have a guide on building stud walls available on our website. If looking for additional sound insulation, particularly within a busy commercial or work environment, then hanging acoustic panels around your room can further lower the noise levels by absorbing sounds.

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The Best Sound Proof Insulation to Use on an Outer Wall

For an outer wall, you have a few key options. You can build a stud wall on the internal facing, using mineral wool sound proof insulation within it, and covering it with plasterboard. While this will lose you some floor space it will give you solid acoustic insulation. You can also use cavity wall insulation if you have a cavity wall, while you will need to hire a professional this will reduce the noise coming into your building. You should always get your outer walls checked by a surveyor before installing cavity wall insulation, as it can cause issues in some properties. You can also install external insulation boards on the outside of your building, which can help prevent noises from entering your home or building. To install external insulation boards may require planning permission.

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The Best Sound Proof Insulation to Use on a Floor

Depending on the type of floor you may be able to install mineral wool batts or rolls between the joists. This can help prevent the passage of both airborne and impact noise. However, if looking to add sound proof insulation this may be unfeasible, requiring completely pulling up existing flooring. It is also unsuitable for ground floors built on concrete bases, which will include most contemporary buildings. In those cases, and in others, a sound proof insulation mat can be a great choice, as it can be simply added underneath flooring layers. This can be used in conjunction with mineral wool rolls to give a great level of sound insulation between floors in places like shared living or busy commercial environments. There are also solid insulation boards that can be used as an underlay within the flooring, offering further benefits.

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The Best Sound Proof Insulation to Use in a Loft

For a traditional loft with wooden joists, a mineral wool roll could be used within the joists, offering thermal and acoustic insulation. This would leave you with a cold loft, meaning that cold air penetrates your roof, but does not enter the rest of the building. If looking to insulate so that the loft can also be used you can install solid mineral wool boards within the joists of the room. You could also look to use Polyurethane insulation foam underneath the roof, though this would look quite unsightly.

Other Ways to Help Soundproof Your Building

As we discussed earlier, flanking sound can get through gaps, cracks, and cavities. There are other things you can do to help reduce the passage of sound within your building. Using sealing products within any gaps in walls, particularly for windows or doors, can help reduce noise within your building. Check the window frames and door frames carefully, looking for cracks or gaps. A gap between the door and the wall can undo much of the good from your insulation. Soundproofing doors using traditional insulation materials is not possible, but using solid interior doors in your building will help to lower the passage of sound. Installing double glazing can help to reduce the noise coming through your windows, with a second layer of glass in your double-glazed window blocking sound passage. Another great tip is to install bookshelves over walls where noise is coming through, as a full bookshelf can help absorb noise.