When soundproofing the apartments, the customers are often not paying adequate attention to the sound insulation mounting technique. It is widely believed that the effectiveness of sound insulation is 100% dependent solely on the sound insulation materials themselves. Unfortunately, it is the sellers of soundproofing materials who commonly cultivate this myth and mislead the customers by telling them: “The most important thing is to put the sound insulation and this is enough to ensure the silence in your apartment”. Before starting the soundproofing works in your apartment, it is necessary to understand what makes the sound insulation efficient and how the maximum results can be achieved.

THE BEST SOUND INSULATION CONSISTS OF THREE COMPONENTS AS FOLLOWS:

1. Efficient sound-absorbing materials. It is simple: choose only the professional sound-absorbing materials with certified acoustic properties. Specially designed for sound insulation of apartments, all MaxForte materials provide maximum noise absorption!
   

2. Proper design. Soundproofing is a property of a structure but not of a specific material. Therefore it is not enough just to buy the material you like; it is important that the structure it is used in has been correctly designed from the point of view of soundproofing. The increase in sound insulation can be provided not only by the MaxForte sound-absorbing materials but also by the regular building materials like drywall, gypsum plasterboard sheets, plywood, etc. However, the noise from the neighbors can only be significantly reduced by alternation of the MaxForte soft sound-absorbing materials and the solid sound-reflecting building materials.
   
   For example: The noisy neighbors live behind your wall. So you have bought the sound-absorbing MaxForte-ECOslabs and placed them over this wall. At the first glance, the entire wall is soundproof and you think that the noise should disappear. In reality, a noise reduces only slightly! The reason is simple – because of wrong design. Even the most efficient sound-absorbing material should be covered with a massive tight layer that will reflect the sounds back to the neighbors. You can achieve the desired silence only by completing the structure with drywall. Let’s consider the reverse situation: a drywall is mounted without a sound-absorbing layer between the profiles (the empty frame). Such structure is able to enhance the noise behind the wall due to the resonance of sound waves in the air cavity between the profiles. If mounted without the acoustic slabs, the drywall will always resonate and reduce the sound insulation.
   
   

3. High-quality sound insulation mounting. Even the correctly designed sound insulation may be inefficient if the sound insulation has been mounted with errors. When mounting the sound insulation, it is important to follow strictly the manufacturer’s instructions. Otherwise the noise reduction may be lower than the calculated values.

   The recommendations for choosing the materials and structures are presented on our website. For detailed information you may refer to the relevant articles (floor soundproofing, walls soundproofing, ceiling soundproofing, apartment soundproofing, etc.). You are always welcome to contact us for getting the professional advice from our experts. However, the issue of mounting of sound insulation in apartments is often neglected. Therefore, now we are to discuss the nuances of mounting and clarify the typical errors reducing the effectiveness of sound insulation.

STRUCTURE «TUNING»

The first error which may impede the achievement of silence is the desire to “improve” the manufacturer’s soundproofing layouts. Moreover, the proposals for "tuning" may be expressed by both the customers and the builders. Although the desire to adjust and improve the design is commendable, we must state with full responsibility that the quality of sound insulation, at best, will not be changed due to such “improvements” but at worst it may drastically decrease, down to zero. The rules of acoustical engineering cannot be described by logic or the ordinary life experience. As a rule, the people’s comprehension of acoustics is erroneous and incomplete. The sound insulation is often tried to be made by analogy with the thermal insulation, but this is a wrong approach. Needless to say, the sound insulation cannot be improved by various modifications based on the initially wrong beliefs but, most likely, it will be reduced.

Never make alterations to the designs presented on the website. Strictly follow the mounting instructions!

QUALITY OF WORKS

The sound insulation mounting is not a complicated work. All our structures are designed to be mounted by the ordinary workers engaged in the repair of apartments. The ceiling and walls soundproofing structures are based on the KNAUF dry construction designs. Since the suspended drywall ceilings are usually mounted in the most of apartments, the workers are already accustomed to work with metal profiles and drywall and such work is of no problem for them. The sound insulation of the floor is commonly made as a "floating" screed over the soundproofing layer. The word “floating” should not be embarrassing: in fact, this is a common M300 sand-concrete screed applied over the sound-absorbing material. At the same time, the screed does not have rigid constraints with either the floor or the walls. That’s why it is called a “floating” screed. The floor soundproofing mounting is also easy: you have only to place the sound insulation over the floor slabs (or the rough screed) as per instructions and apply the “floating” screed according to the building codes.

However, although the sound insulation mounting seems easy, it is associated with certain difficulties and pitfalls. Everyone knows the saying "The devil is in the details". This is just a case of sound insulation! The first thing to understand: the sound insulation must be mounted in good faith and slowly. The split in the drywall or the rigid contact between the profile and the wall may seem the trifles, but such mounting errors may significantly reduce the efficiency of sound insulation of the apartment!

ПWhen mounting the sound insulation, it is necessary to observe the proper vibration insulation and the tightness of the structure. Let's discuss these important issues in more detail:

Why can we hear our neighbors? This is due to the vibration of the enclosures which separate us from the neighbors. Let’s consider the case of noisy neighbors behind the wall once again. The noise they make reaches and presses the wall thus swinging it. Vibrations pass through the wall and make it vibrating at the surface from the inside of our apartment. The amplitude of vibrations is only a few microns in size and invisible. However, the size of the wall is large and, accordingly, the emission area is also significant. That’s why we can hear the noise!

I think it is clear now why the vibration insulation of structures is so important during the mounting. Our purpose is to get the structure which is maximally vibroinsulated from the building (and it is of no importance whether we soundproof the ceiling, the walls or the floor). Each rigid constraint functions as a bridge for the sound, i.e. a vibrations conductor reducing the final result.

It is clearly shown below how the errors in making the “floating” screed can reduce the sound insulation of the floor. The red line is the level of impact noise from the apartment below in the absence of a screed. The blue line is the noise level when the screed is made correctly and no acoustic bridges are available. The chart demonstrates that high-quality mounting of noise insulation significantly decreases the noise in the apartment from downstairs! The green and the yellow curves show the same construction made with defects: one (green) and ten (yellow) acoustic bridges accordingly. In this example, the acoustic bridge is only a 3 cm long cement grout connecting the screed with the wall. We can see that the green curve is located much higher than the blue one. Therefore, even a single acoustic bridge decreases the result significantly!

Pay special attention to the tightness of the structure when mounting the sound insulation! A sound, like a water, is able to seep into any gaps. So, even a small hole in drywall or a gap in its abutment to a wall can noticeably reduce the sound insulation.

For example: If a wall which is 15 m2 in area has a through hole with dimensions of 20 x 20 mm (i.e. the area of the hole is 40,000 times smaller than that of the wall), then the sound insulation of the wall will decrease by 20 dB !!!

Let’s consider the mounting nuances and the typical errors in sound insulation of ceiling, walls and floor. We are going to give you the valuable recommendations to simplify the mounting of noise insulation and improve the noise reduction:

When installing sound insulation on the walls, avoid (if possible) attaching the profile to the walls. KNAUF PS 50/50 mm wall profiles are enough rigid to be tightly fit between the floor and the ceiling without attachment to the insulated wall (if room height is h < 3 m). The absence of constraints between the profile and the wall will significantly improve the result. If the attachment of profiles to the wall is necessary (because of a thin construction or a large room height), be sure to use the special MaxForte vibration insulating hangers: VibroStop Standart or VibroStop PRO

Guide profiles and cladding sheets should be vibroinsulated along the perimeter. Rigid abutment to the ceiling, the walls or the floor is not allowed. MaxForte damping tape should be used for damping.

The width of the tape should be selected depending on thickness of the metal frame and the drywall cladding (drywall sheets will add 2-2.5 cm, depending on thickness). We recommend to choose a 10 cm wide tape. This width is enough for any structure, and the protruding excesses can be easily cut after the mounting of sound insulation.

When mounting the sound insulation on the ceiling (in contrast with the walls), the frame should always be attached to the ceiling since the ceiling can not hang in the air. By analogy with the walls, the special anti-vibration fasteners should be used on the ceiling in order to reduce the vibrations transmitted from the floor slabs to the profile.

This is especially important for sound insulation of the ceiling because the noise from the upstairs is usually the impact noise (footsteps, moving furniture, falling objects) which is exactly the vibrations. Do not allow the workers to use the conventional KNAUF direct hangers. The use of conventional hangers leads to the formation of acoustic bridges and reduces the sound insulation of the wall or the ceiling!

All recommendations given above for sound insulation of profiles and drywall sheets along the perimeter in the course of the walls soundproofing are also valid for sound insulation of the ceiling. But a nuance should be taken into consideration: after the metal profile is assembled and hanging on the vibration insulating hangers of the guide profiles along the perimeter, the fired pins attaching the guide profiles to the walls should be necessarily unscrewed. What purpose it should be done for? When using vibration insulating hangers, the ceiling will settle for approximately 1.5-2 mm under the weight of the drywall (due to the shrinkage of the elastomer in the vibration insulating joints). But there will be no shrinkage along the walls where the profile is rigidly attached to the walls. As a result, the ceiling will be made uneven and lens-shaped because of sagging by the center. By removing the fired pins, we eliminate the rigid constraint between the profiles and the walls. Therefore, the shrinkage will be even under the weight of a drywall and we will get a flat ceiling!

The most important thing when soundproofing the floor is to exclude the rigid constraints between the “floating” screed, the ceiling and the walls. The negative effect of acoustic bridges on sound insulation is able to negate all the efforts (see the charts above)!

When mounting the sound insulation, make sure that the layer of material is applied continuously and without breaks. The very important thing to be remembered is that the soundproofing layer must also have a bent on the walls, and the strip of insulating material along the walls must rise above the screed level! If the screed is applied in accordance with the instructions, both you and your neighbors will be satisfied with soundproofing.

IMPORTANT! Sometimes the workers forget to bend the sound insulation on the walls. As a result, the screed is rigidly connected to the walls along the perimeter and the acoustic bridges are formed. This is the most common error found on sites.