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Living next to a busy road or sharing a party wall with noisy neighbours is an unpleasant experience which can cause unwanted stress, restlessness and even lead to a number of health related problems.

If you’d like to restore some tranquility to your home, you may wish to consider learning how to soundproof a stud wall and other internal structures.

With proper stud wall sound insulation, you will be able to diminish sound transmission, and reduce impact as well as airborne sounds.

However, it is important to identify key factors relating to stud wall soundproofing to ensure that the results achieved are optimal.

1. Identify Weak Points

Tackling sound is a tricky business.

Sound travels at very high speeds, and is able to pass through walls more easily if it finds a weak point where there’s least resistance.

Hence, the most important first step is to identify weak points, as you are only as strong as the weakest points.

Any acoustic treatment will rely highly on whether you’ve fully found and remedied areas where sound transmission may occur.

Even if you line the entire wall with high grade soundproofing material, sound will manage to pass through even the smallest gaps, cracks or weak points if left untreated.

It’s very important to consider any obvious gaps or cavities, as well as columns, structural supports or anything else which could offer a pathway or flanking route for the sound to travel through.

2. Types of Noise

Did you know there are different types and colours of noise?

Hence, you need to be aware of the various types of noise you could be dealing with specifically when you come to soundproof a stud wall.

This will greatly improve your chances of achieving far better results.

Airborne Sound

Airborne noise refers to any sounds that are transmitted through the air.

This includes noise such as overhearing conversations or music being played next door.

The sound waves are picked up and carried by the air.

Whilst moving through the air, the sound waves collide with any object in their path.

When the sound hits a stud wall for example, the collision will cause vibrations to pass through that wall, as well as into the spaces beyond.

Hence the noise can travel through the wall and into your rooms.

Structural/Structure-Borne Sound

This type of sound transfer results from impacts or vibrations that occur within a building’s fabric.

Consequently, the sound is radiated from an adjacent surface, which will vibrate as a result.

To better understand this type of sound, a good example is the sound made by footsteps going up or down stairs.

These sounds are heard due to the fact that the initial impact of footsteps made on the stairs leads to vibrations, which manage to be overheard through the construction of the stairs and transferred through the building’s structure.

Impact Sound

Impact noise is similar to the previous type of noise, but in this case the sound is created when an object impacts another.

This leads to the generation of sound and its subsequent transmission from another surface.

3. Reducing Flanking Noise

Sound can travel through any gaps it finds and along or within structures, such as walls or structural steels for example.

These could be minor cracks in walls or larger cavities such as floor cavities.

When soundproofing a stud wall, it’s essential to consider the importance of reducing the chances of flanking sound transfer through the structure, the stud frame, the coupling to the floor below and ceiling above as well as associated floor cavities between floor joists.

This may be quite difficult, as in many circumstances floor joists are shared by your neighbouring property.

As a result, it soon becomes apparent how easily sound is transferred from one property to another when such weak points are present.

Thus, if you’re going to soundproof a stud wall, you need to look not only at the wall itself but also whether your floor joists run through to any party walls with your neighbour’s house.

An easy way to do this is to check which direction the floorboards run.

In cases where the floorboards run parallel (in the same direction as the wall), it’s most likely your floor joists are running perpendicular into the wall, thereby increasing flanking sounds transferred between your house and your neighbours through the joists.

The simplest and most effective way to reduce amplification of sound within floor cavities and flanking sounds from passing through the floor cavities, is to add sound insulation between the floor joists.

In order to do this you will need to remove some floorboards.

Then start to infill cavities against the wall using open cell acoustic insulation such as Acoustiblok QuietFibre.

It is very versatile and comes in different thicknesses to include 25mm, 50mm 75mm and varying densities from 45kg/m3, 60kg/m3, 80kg/m3, 100kg/m3.

It’s best to come back into the room at least around 600mm, or approximately the width of the slab but of course filling the full length of each cavity will be greatly beneficial both acoustically and thermally.

An additional measure to insulate the joists themselves to reduce vibration and flanking transmissions through their own rigidity, would be an installation of an isolation membrane such as Acoustiblok 6mm Isolation Membrane over the top of the joists.

This could be either in strips over the joists or for a better acoustic level fitted across the entire floor.

4. Soundproofing a Stud Wall

When it comes to soundproofing a stud wall, it would be advisable to employ a number of techniques.

Your main aim is to increase acoustic value and thereby reduce sound transmission.

Firstly decide the preferred approach and whether you wish to open up the existing stud wall to gain access to the stud frame and cavity by removing the existing finishing board.

Alternatively add additional materials to the existing wall which may prove to be less invasive that doesn’t involve removal of any existing plasterboard or drywall.

The fact that there is a sealed stud in between makes these walls susceptible to sound transmission through amplification of sound within open cavities.

This is because the sound waves will reverberate/echo and become considerably louder due to the cavity, as they will be bouncing and vibrating around inside the space.

A key deciding factor as to the required approach may be to establish if the existing cavity has cavity insulation in between the stud frame.

These cavities need to be filled with open cell insulation to provide an absorption of acoustic energy to reduce resonance.

Either of the approaches above will ultimately result in an open stud wall/cavity space which can be filled as described.

Following this would typically be an application of Acoustiblok 3mm Isolation Membrane to the stud frame.

This unique material in simple terms converts acoustic energy into heat energy by way of thermal conversion and achieves the highest levels of effect of any material or principle, mm for mm.

Where at all possible, apply on the noise source side of the assembly.

Where appropriate incorporate material to both sides of the walls to achieve even better results.

When applying the membrane, it is also important that all the heads of the fixings are properly countersunk.

It is highly recommended that you apply silicone sealant to the heads in order to soften and further reduce any impact and flanking sound transmissions.

Mass, density and absorption are all important to mitigating sound waves and consequently preventing them from making their way any further and traveling through the walls.

To add more mass to stud walls, you can either add more drywall to the existing walls, or opt for a double layer of sound insulation membrane.

The latter is more costly but more effective than drywall as it is not simply relying upon density, rather very cleverly converting from a problematic sound into a less problematic trace element heat energy.

5. Finishing

As noted earlier, there are various steps involved in ensuring your stud walls are properly soundproofed.

You want to make sure that the entire stud wall is sound tight.

Hence you need to make sure that all finishes applied and products used are the most suitable in terms of their soundproofing capabilities.

This includes the acoustic insulation as well as the sealants, caulks and jointing tapes used throughout the procedure.

You need to ensure that you seal any areas of potential weakness, to prevent any possibility for sound to pass through, no matter how tiny the gap may be.

Conclusion

By following the steps outlined above, you should be able to effectively increase the acoustic levels of your stud walls and reduce sound transmission from neighbouring rooms and properties.

The principles of mass, decoupling and sound dampening need to be observed with care, and the use of suitable sound insulation products is of the essence in achieving the desired results.