The problem of noise behind the wall can occur to anyone, regardless of the type of the house. Laughing and screaming, TV, barking dogs and other noises from neighbors disrupt our quiet life. Unfortunately, the problem of increased noise may arise suddenly: the ordinary change of neighbors can turn into a headache and a need in soundproofing the walls.
The quality of house construction often leaves much to be desired. To provide good noise insulation and meet the requirements of the Building Codes and Regulations (SNiP), the walls should be thick and massive, but this makes an extra cost for the developer. In construction of modern monolithic houses, the affordable porous types of concrete (like foam concrete blocks or aerated concrete blocks) with poor sound insulation are used in order to save money. The wall thickness in panel houses is reduced for the same purpose. The weaknesses of each type of houses are described separately below.
BEARING-WALL HOUSES AND FRAME-AND-PANEL HOUSES
In bearing-wall houses and frame-and-panel houses, the problem of noise behind the wall is extremely topical. The sound insulation is greatly reduced by cracks and gaps which always exist in the bearing-wall houses.
The cracks appear over time as the house shrinks but sometimes they exist originally if the house is built poorly.
HOW THE GAPS MAY BE CORRECTLY CAULKED
All the gaps must be caulked before starting the works on sound insulation. It should be said immediately that the construction foam can never be used! It seems to be a simple and easy way to solve the problem; however, the construction foam cannot provide the adequate sound insulation: it cannot practically delay the sound wave.
Small gaps can be caulked with a conventional silicon sealant. A non-hardening type is preferable since it remains elastic and does not shrink over time.
Large gaps should be caulked tightly with pieces of mineral wool dipped in cement mortar. Finally, the gap should be puttied with non-shrinking putty.
If the edges of the gap are loose and crumbling, they must be widened and prepared before caulking.
Another problem that significantly reduces the sound insulation is the through holes for electrical outlets and junction boxes in the wall adjacent to the neighbors.
Be sure to move the outlets to the new places, and then caulk the former places by analogy with the gaps.
MONOLITHIC HOUSES
In the monolithic houses, the problem with sound insulation of walls is even more acute than in bearing-wall houses. It is the tenants of these houses who say: “It can be heard as if the wall does not exist!”.
Indeed, the monolithic houses belong to modern constructions which feature the inter-room walls made of porous low-density concrete blocks or hollow bricks. For comparison: the density of a solid brick is 1800 kg/m3, and the density of a foam concrete is 400-500 kg/m3. The walls made of foam concrete blocks have a mass of 4-5 times less compared with the walls of same thickness made of bricks or concrete. This is the reason that the tenants can perfectly hear the neighbors. Even the calculated soundproofing of walls in monolithic houses is not exceeding 45 dB. If the defects of brickwork are taken into consideration (the gaps, the inter-block joints not filled with mortar), it turns out that the actual sound insulation is even less.
Before starting the works on sound insulation, the walls in the monolithic houses should be plastered up to a layer of 1-2 cm. It should not be necessary to level to the leads since this will be a final step after the mounting of sound insulation. By the way, if sound insulation is assembled on a metal frame, then the walls can be easily levelled with the profiles; but this will be reviewed below.
Why do we need to plaster the walls? First of all, the plaster will eliminate all the defects of brickwork, and secondly, it will increase the mass of the walls – this will raise the noise insulation by 3-5 dB.
BRICK HOUSES
The problem of low sound insulation of walls adjacent to the neighbors may arise even in a brick house! Unfortunately, the internal walls are not always of the necessary thickness, and sometimes they are made even not of brick. There may be several reasons for such poor walls – for example, it may be the former communal apartments rebuilt into the separate apartments. It is clear that the walls erected in a hurry will not meet the norms of noise insulation.
HOW TO CHOOSE THE OPTIMAL SOUND INSULATION
After all the preparatory works are fulfilled, you can start soundproofing the walls. First of all, you need to choose the required design.
There are framed and frameless soundproofing systems.
In the first case, the profile should be built and the MaxForte sound-absorbing materials should be placed in the space between the profiles of the metal frame. Finally, the structure should be covered with gypsum plasterboard sheets and drywall.
Frameless systems are essentially the same but only in the finished version: the sound-absorbing slabs are already glued to the gypsum plasterboard sheets. The panels should be mounted to the walls and also covered with drywall.
The framed and the frameless systems of same thickness are identical to each other in the level of sound insulation. Nevertheless, all sound insulation structures by our company are based on the framed options. In our opinion, they have a number of advantages that favorably distinguish them from the frameless systems:
- Framed systems automatically level the surface of the wall. Even if the wall is curved, there is no need to spend money on plaster and leveling works. When mounting the profiles, the workers will set a plane that the drywall should be attached to. Frameless systems entirely repeat the relief of the wall so the walls need to be levelled before mounting the panels!
- Fewer attachment points. The profile can often be tightly installed between the walls absolutely without attachment to the ceiling. But even if such attachment is necessary (room is more than 3 meters in height or significant loads are planned), the framed systems require the 3-4 times less number of the attachment points in comparison with the frameless systems. Although the attachment points are vibration-insulated, it must be understood that no elastomer can completely remove the vibration load. So the less the attachments, the better!
- The frame-attached cladding can withstand large cantilever loads. You can easily hang on such walls the air conditioning, TV, the kitchen cabinets and the other heavy objects.
- Sound insulation can be mounted on the frame by any worker engaged in repairing apartments since the standard KNAUF construction technology is used.
Sound insulation of the wall is not just the MaxForte sound-absorbing materials but it is the structure as a whole!
Therefore, if you have chosen the wall noise insulation system as per framed technology, you need to find out the factors that the increase in sound insulation depends on, and do your best to assemble the structure as correctly as possible.
FACTORS AFFECTING SOUND INSULATION
- The thickness of the structure. The increase in thickness leads to an increase in sound insulation, so the more centimeters the cladding "consumes", the quieter becomes your apartment.
- Tightness. Gaps and holes in gypsum plasterboard and drywall cladding can significantly reduce the efficiency of structure. The joints between the sheets and the abutments of cladding to the adjacent surfaces must be sealed with silicone!
- Cladding weight. Each additional sheet of gypsum plasterboard or drywall will increase the sound insulation. Usually, the time-honored two-layer lining comprising 10 mm gypsum plasterboard + 12.5 mm drywall is used in the apartments. But you can use a three-layer and even a four-layer option!
- Vibration isolation. To achieve the maximum results, you should eliminate the rigid constraints between the mounted cladding and the wall to be isolated which is adjacent to the neighbors. Each rigid constraint is an acoustic bridge reducing the sound insulation. If the attachment to the wall is necessary, the special VibroStop anti-vibration fasteners should be used.
Compliance with the above recommendations will significantly increase the sound insulation of the walls and enhance the acoustic comfort in your home! The optimal composition and thickness of the structure will be advised by our specialists on the basis of the wall thickness, the material it is made from and, of course, your wishes!