- What is noise
- Noise abatement techniques and principles
- Sound insulation of load-bearing walls
- Soundproofing partitions
- Sound insulation of floors
- Soundproofing windows
- Soundproofing doors
- Sound insulation of engineering systems and communications
- Soundproofing on site
- Summing up
Today we will talk about what measures need to be taken to ensure acoustic comfort in a private house, define the basic principles of sound protection, debunk common myths about the sound insulation system.
Ask any owner of a private house if he knows what soundproofing is, and you will hear a confident positive answer. But most of them will note that their home is not comfortable enough in terms of acoustics. The thing is that a culture of professional private construction is just emerging in our country. We can start work without a detailed design, with us very often the customer manages the work himself, thus, he is left alone with the construction team. The developer is plunged headlong into a sea of technical problems and tasks, while the issues of sound insulation are usually relegated to the background or are solved on the basis of “experience” and “practice” rather than exact calculations. Unfortunately, traditional ideas about effective sound insulation of a home are full of myths and misconceptions. As a result, the problem is already indicated during the operation of the building, but it is extremely difficult and expensive to fix something at this stage..
Optimal building acoustics is one of the most important components of a sense of comfort and coziness from being inside a living space. In turn, constant sound pressure in a house can cause psychological and physiological discomfort, stress, impairment of hearing and general well-being in its inhabitants. However, excessive silence (the noise level is below 10 dB) is the cause of anxiety and anxiety – sounds and noises are necessary for a person, the main thing is to reach a compromise value of their level. Noise indicators in residential premises in the range of 10-25 dB are considered comfortable. Building and sanitary standards for housing do not allow exceeding the mark of 45 dB.
What is noise
What should we isolate ourselves from? Noise is our main enemy. To effectively deal with it, it is necessary to study its main types, causes of occurrence, the nature of the movement. Noises are chaotic combinations of sounds that do not carry any information for a person and negatively affect his nervous system. Sound, in turn, is a physical phenomenon that is caused by wave oscillations of the medium. Sounds are characterized by amplitude and frequency.
Noise sources can be located both indoors and outdoors. Unwanted sounds arise from the operation of household appliances, movement and activities of people, the functioning of in-house engineering systems and communications. Serious discomfort is caused by external constant noise coming from the railway, highway, airport, since they have the highest level.
There are several types of noise in construction acoustics: air, impact, structural.
Airnoise is caused by wave vibrations of the air (music, crying of a child, a running car engine …) The efficiency with which structures reduce noise levels is assessed by the sound insulation index Rw and is measured in decibels.
Shocknoise occurs due to mechanical influences on building structures, most often on floors (steps, moving furniture …) The level of sound insulation against impact noise Lw reflects the corresponding characteristics of walls and floors, it is also measured in decibels.
Structuralnoise is a special sound vibration that moves through the structure of the building. That is, this definition is based on the classification by the type of propagation, and not by the principle of excitement. Both impact and airborne noise can become structural. So, for example, the sounds of a piano through the air reach uninsulated partitions and ceilings, are transformed into structural noises and are carried throughout the building structures throughout the house..
Depending on what type of noise appears inside the premises, a specific set of measures is applied to isolate them. We must use artificial barriers to reduce the noise level to a comfortable level.
Noise abatement techniques and principles
So, our first task is to isolate the premises from outside airborne noise. Everything here is quite simple, the characteristics of the enclosing structures – windows, doors, external walls – come to the fore. The better their sound-reflecting properties, the less unwanted sounds will get inside the house. By choosing certain insulating materials and technologies, we can manipulate such properties.
Another task is somewhat more difficult – to localize and scatter sound waves in the room, preventing their transformation into structured noise. In this case, the sound-absorbing characteristics of internal structures are very important, which largely depend on the competent choice and correct use of certain building materials..
For protection from airborne noise, structures made of massive, but at the same time porous materials are excellent. Then dense front surfaces reflect some of the sound energy towards its source, and the pores absorb and scatter some of the sounds. Indoors it is rather difficult and it would not be rational to use too massive elements, therefore multilayer structures come to the rescue, which operate on a similar principle: cladding (brick, drywall, gypsum board, lining …) reflects noise, and the layer is in the form of a fibrous material (mineral wool ) or soundproof membrane – dissipates and absorbs.
Shock noises in a private house can be neutralized by using elastic porous materials in floor structures as substrates and gaskets that dampen possible vibrations. It can be expanded rubber, cork, dense polystyrene foam, polyurethane, porous PVC. Fibrous materials laid in the voids of non-monolithic ceilings have proven themselves to be excellent in the fight against impact noise.
In order to exclude the propagation of structure-borne noise, structures that are especially susceptible to increased sound pressure are not rigidly mounted to other building elements, but through various gaskets. An example is various designs of floating floors, frame partitions made of plasterboard, adjacent to load-bearing ceilings and load-bearing walls through damping tapes made of expanded polyethylene (dichtung), suspended ceilings on hangers with gaskets that damp vibrations.
Challenge number three is to reduce the generation of noise inside the home. To do this, it is necessary to isolate sources of unwanted sounds – household appliances, communications. Firstly, noisy equipment (forced ventilation units, pumping stations, washing machines …) should be installed or mounted through elastic pads. Secondly, it is recommended to place it at the maximum distance from the protected rooms – a bedroom, a study, a nursery. If possible, special, well-insulated utility rooms, such as a laundry room, a boiler room, and so on, are equipped for noisy engineering equipment. Sometimes some of its elements are even taken out of the building – for example, onto the balcony.
An effective method of increasing the acoustic comfort in the home is the competent design of the interior space. The premises should be divided into those that especially need isolation from extraneous noise (bedroom, study, children’s room …) and those that are a source of unwanted sounds (playroom, living room with home theater, workshop, billiard room, utility rooms …). They are grouped and located at a distance from each other. Moreover, sometimes it makes sense to place protected living rooms with windows to the inner courtyard, and other rooms to the side of the facade..
It is more efficient and cheaper to solve sound insulation issues at the design and construction stage. In any case, the soundproofing of a private house must be considered as a complex system, where all the elements are interconnected and have particular importance. All acoustic factors acting on the building must be taken into account. One way or another, all structures, elements and units of the house should be isolated: external walls, partitions, ceilings, floors, ceilings, communication channels, windows, doors – more on that later.
Sound insulation of load-bearing walls
Outside walls made of massive materials themselves have good sound insulation characteristics, and the more “powerful” the structure, the better. Some materials do the job better than others. Monolithic concrete walls, which do not have seams and possible cracks, reflect well external noise. Shell rock and foam concrete, due to their porous structure, not only reflect, but also extinguish and absorb sound waves. Silicate and porous bricks “work” well (not to be confused with hollow bricks).
To improve the resistance to external noise, the outer walls are made multi-layer. Various combinations of several brick layers, separated by soundproofing mineral wool, or with an air gap possible.
Sound insulation is improved with the competent construction of hinged ventilated facades with a heat insulator, when extraneous noise under the cladding is excluded.
Exterior walls lined with plasterboard have good acoustic properties. It should be a frame technology using a layer of mineral wool. It should be noted that brackets and guide profiles must be fixed through elastic spacers, the sheets must be screwed with a gap from the floor and ceiling, which will subsequently be sealed with a non-hardening sealant, for example, acrylic. In especially serious cases, a completely independent frame from a partition profile can be used, the so-called screen, at some distance from the main wall, of course, it is also filled with cotton wool.
Facing the outer wall with drywall sheets using mounting glue practically does not improve sound insulation, and sometimes causes the opposite effect – the appearance of an oscillatory system, sound resonance. This also applies to double-layer walls insulated with foam using wet technology. By the way, contrary to popular belief, foam and extruded polystyrene foam, being good insulation materials, do not help to protect against airborne noise from the outside..
As you can see, the use of massive structures in combination with acoustic mineral wool is the most effective method to improve the sound insulation coefficient of enclosing structures. Note, however, that fibrous slabs or mats must be securely fixed with soundproofed fittings and placed in cavities with minimal gaps. By increasing the wool layer, we improve the acoustic performance of the entire structure..
Interior partitions mainly prevent the propagation of airborne noise. But you should also take measures to prevent the transformation of unwanted sounds into structural noise..
Walls made of mineral materials (brick, concrete, gypsum block …), as a rule, have fairly tolerable acoustic characteristics and do not require additional sound insulation. In special cases, they are sheathed with plasterboard from the side of the protected area, thus obtaining a multi-layer structure with a layer of mineral wool. Massive partitions better than light frame ones cope with low-frequency noise (home theater subwoofer, engineering equipment), therefore, in some cases they look preferable, even if their overall sound insulation index Rw is lower.
Frame partitions assembled on metal profiles or wooden beams must be insulated with sound-absorbing fibrous materials. If there is a need to provide a more serious barrier to the propagation of sounds, then the thickness of the acoustic wool should be increased. For this, wider profiles are used, for example, the most popular sizes of galvanized CW and UW racks are 50, 75, 100 mm. Note that the cotton wool should fit over the entire internal width of the frame, therefore, the profile parameters largely determine the acoustic characteristics of the finished wall..
We must not forget that cotton wool intended to absorb sounds must work with an effective reflective layer. The more massive the cladding is, the more reliable the sound insulation. Heavy sheet materials, gypsum board, OSB, gypsum board, chipboard for these purposes will be preferable to piece, such as lining. Even better, the sound is localized by using multiple layers of cladding with overlapping joints..
Sometimes they resort to the construction of walls with several independent frames, but they are not very effective due to the fact that the sound insulation index in complex multi-layer structures increases non-linearly. So a partition with one frame 75 mm wide has only 25% less sound insulation index than with a twin frame according to the 75 + 75 scheme.
To combat structure-borne noise, the partition guide profiles are attached to walls and ceilings using elastic bands. Gaps are left between the sheathing and the enclosing structures, which are carefully sealed with non-hardening sealants.
Sound insulation of floors
The overlap of a multi-storey building must withstand airborne and impact noise. This problem is solved by soundproofing the upper level floor and the lower ceiling. Airborne sound waves are successfully trapped by concrete slabs or a pie of beam floors, consisting of sound-absorbing materials and rough sheathing. A little more complicated is the case with the neutralization of impact noise..
In most cases, you have to resort to various floating floor designs that do an excellent job. They are not rigidly connected to the main elements of the building. The concrete screed is placed on a layer of foam or extruded polystyrene foam. Lags of wooden floors are mounted through elastic pads. The leveling pad for dry screed prefabricated floors also dampens shock vibrations. Floating floors are arranged after the installation of partitions, so they are isolated from floors in other rooms and do not transmit structure-borne noise. Damping tapes made of elastic foam materials must be installed between floating floors and walls..
A certain role is played by clean floor coverings, which can significantly affect the acoustic comfort of rooms. For example, linoleum, carpet, cork perfectly dampen and absorb noise. Laminate and parquet flooring will also improve the acoustics when quality substrates are used..
False ceilings play an important role in the sound insulation of floors. Mineral wool can be embedded in the metal frame, and a simple air gap in the ceiling space is involved in the localization of noise. To avoid structure-borne noise and resonating vibrations, ceiling profiles should be mounted to the walls through elastic bands; it is recommended to install vibration damping gaskets under the suspensions. Stretch ceilings that are not attached to the ceiling at all and are made of non-resonating PVC films and fabrics have proven themselves well.
The resistance of a building to street airborne noise depends not only on the characteristics of the outer walls, but also on the sound insulation quality of the windows..
The first thing you should pay attention to is the glazing area, with an increase in which the acoustic comfort in the premises will necessarily deteriorate..
An important factor is the choice of the correct glass unit. Not always a multi-chamber glass unit better insulates against noise, the reason for this is the relatively small air gaps between the glasses. The widest multi-chamber double-glazed windows, in which spacer slats of different widths are used, have special sound-proof characteristics, thus avoiding resonances caused by strong traffic noise. Enhance the soundproofing effect by using massive glass of various thicknesses. In any case, the thicker the glass and the larger the air gaps between them, the less noise windows pass through. If glass with special films or triplex is used in the production of a glass unit, this will also have a positive effect on sound insulation..
The shape and configuration of the window affects acoustics. Rectangular windows are “quieter” compared to square ones. The division of the light opening by bulkheads from the profile into smaller light fields using several glass units significantly increases the acoustic efficiency.
For sound insulation, the degree of tightness of the porch is very important, which can only be ensured by well-adjusted fittings and a high-quality seal. The third, additional contour of the seal will also not be superfluous..
Naturally, it is necessary that the window be correctly installed in compliance with all the rules for organizing assembly seams. The use of soundproofing materials in hollow slopes is highly encouraged.
The use of ventilation valves spoils the acoustic picture a little, but no more than a sash open for ventilation. And the new valves have a kind of labyrinth for damping sounds.
Doorways are one of the transmission channels for noise. This applies to both the entrance group and interior doors. The solution to the problem again lies in the use of the largest possible massive boxes and canvases. It is possible to improve the acoustic performance of doors by using structures with a dense rebate.
Designs with a reliable D-section seal located around the entire perimeter have more effective sound insulation. Ventilation grilles and gaps under the curtain have a negative effect on the acoustic picture inside the room. Therefore, in certain cases, preference should be given to door blocks with a threshold and a blank canvas with an influx, of course, without glazing and grilles.
To soundproof the entrance to the house, double doors are often used, the formed slopes between which are insulated with mineral wool. Moreover, the outer sheet can be filled with fibrous sound-absorbing material..
Sound insulation of engineering systems and communications
Communication channels are often not only a kind of bridges for the transmission of sounds, connecting different rooms, but sometimes they become powerful generators of airborne noise, often turning into structural ones. There are several ways to solve this problem:
- All communications should be fixed to the supporting structures through elastic spacers and fasteners.
- Heating, water supply and sewerage pipes (especially risers) are wrapped with acoustic mineral wool and sheathed with boxes.
- The ventilation ducts are insulated with noise-absorbing materials.
- Ventilation openings are covered with grilles with curtains, curtains, blinds.
- Installation and assembly electrical devices (socket outlets, distribution boxes, built-in cabinets) are maximally sealed.
Soundproofing on site
Oddly enough, but most of the outdoor airborne noise can be stopped even outside the private building. So in Europe, acoustic screens are very often installed along busy highways that pass near residential areas. They are also actively used along railway tracks, near existing construction sites, production workshops, children’s playgrounds, noisy sports and shopping facilities. The noise shield reflects or absorbs sound waves, forming an “acoustic shadow” behind it. Sometimes it acts in combination, combining in its design both sound-absorbing panels with perforation and fiber filling, and reflective elements made of rigid materials..
Such barriers are located at the border of the site, as close as possible to sources of noise. They should have a significant length and height from 3 meters, which, however, does not always have a negative impact on design, since there are transparent screens made of special glass and polycarbonate.
Several rows of green spaces at the border of the property will also help reduce the sound pressure on your home. Climbing, bushy plants on a fence or facade can also dissipate and dampen most of the noise..
We examined the main elements of sound protection of a private house and can already draw some conclusions:
- Sound insulation is more dependent on the type of structure than on the properties of materials.
- Particular attention should be paid to the abutment of various building elements to each other, using elastic damping gaskets and carefully sealing the seams.
- The more massive the structure, the better the sound insulation.
- Wider insulator layer or wider air chamber provide better noise protection.
- Instead of massive single-layer structures, you can use light multi-layer.
- Sound absorbing layers should alternate with reflective materials.
- Holes, openings, cracks in structures reduce the level of their sound insulation.
- Sources of noise must be grouped and removed as much as possible from the protected premises.
- All soundproofing materials must be tightly pressed against each other and against structures.
- Not all heaters have sound insulation properties..
- Acoustic comfort can be improved by using elastic finishing materials, pile floor coverings, upholstered volumetric furniture, and thick massive curtains in the interior..
- You can start protecting yourself from external noise already on the site.
In any case, the sound insulation of a private house must be considered as an integrated system, the implementation of which is more efficient and cheaper to carry out at the design and construction stage..