Residents of apartment buildings know firsthand about the discomfort that noise from a sewer riser can cause. The problem is relevant, provided that the old cast-iron drain, due to further unsuitability, was replaced with a plastic version. Noise insulation of pipes will be expensive if you turn to professionals. You can do this work yourself. The main thing is to figure out how to do it right.

Photo: sewer riser

The meaning of the procedure

Completely get rid of annoying noise, unfortunately, will not work. The creation of sound insulation for sewer pipes is carried out in order to reduce them to the lowest possible level. Given the causes of noise in the apartment and the essence of the work performed, the goals can be divided into three main areas:

  • Reducing the degree of vibration of plastic pipes.
  • Prevention of transmission of vibrations from the sewer riser to the structural elements of the building.
  • Creating a barrier to the sound that occurs during the draining of water.

The reasons

Noise isolation of the riser may be required due to the presence of certain circumstances or their presence in the complex. Following are some of them:

  • Poor quality of materials that were used in the installation of the drain. As a consequence, the low resistance of the walls to mechanical deformation.
  • The work was carried out with violations of technology. The design of the pipes in the apartment was not done properly.
  • Inappropriate selection of seal material.

Constant noise can lead to a disorder of the psycho-emotional state of the tenants of the apartment. The direct source of noise is the riser, respectively, the longer it is, the more vibration and extraneous sound it creates.

It should be remembered! The higher the building of an apartment building, the stronger the noise level will be. Especially on the lower floors. Accordingly, it is there that the creation of sound insulation is most important.


In understanding the reasons for this, there is nothing difficult. The streams of water in the process of moving along the riser collide with each other, with air, hit the drain structure itself. The result is the occurrence of vibration and extraneous sounds in the apartment. Noise can be classified into the following categories:

  • Drums. Mechanical impact of water flows on the design of the drain system and their interaction with each other.
  • Air. When water falls down, it collides with the “air barrier”, as a result, though slightly pronounced, but still noise occurs. The presence of such, as a rule, is not the root cause of finishing pipes with soundproofing materials.
  • Structural. The presence of this type of noise brings the greatest discomfort to residents in an apartment building. The flow of water, rushing down the pipe, gives it vibration, which passes through the ceilings, walls, heating pipes, plumbing and other structural elements of the building.


Before proceeding to the issue of proper installation of sound insulation on sewer pipes, it is worth considering in more detail the circumstances that contribute to the emergence and amplification of extraneous sound.

The height of the fall of the wastewater flow, of course, plays an important role, but the pipe manufacturing material contributes no less to the spread of noise. Plastic, despite all its advantages, is significantly inferior to cast-iron counterparts in this regard. Sewer pipes made from the latter are much more resistant to mechanical impact from water.

Photo: cast iron sewer

An alloy of cast iron has a certain feature that allows it to absorb some of the noise that occurs inside the pipe. The structure of this material is somewhat porous. It consists of many small particles, in the process of interaction of which the sound is damped.

A significant role is also played by the fact that due to the «porosity» cast iron gains plaque on its surface, which to some extent also prevents the spread of sound.

To modern analogues of sewer pipes, such advantages are not applicable. Plastic, on the contrary, is often called a kind of musical instrument. It not only does not prevent the emergence and propagation of sound that occurs in the pipe, but, on the contrary, contributes to its amplification, strong vibration.

Photo: elements for arranging the sewer system

In particular, when using this material for the preparation of a general, plaque does not form on the inner surfaces of the pipes. There is a belief that the formation of such a natural «soundproof» layer is not completely inherent in plastic pipes. The opinion is wrong. The fact is that plastic really successfully repels particles from sticking, but only in a vertical position. For example, in the pipe coming from the toilet, plaque is quite the place to be.

The wall thickness of the riser is also important. The higher it is, the lower the proportion of noise penetrating into the room. The resulting and similar situation with the weight of the material of the sewer drain. A large mass allows the system to be less susceptible to vibration.

Unfortunately, this is especially true for apartment buildings, situations often occur that, due to the peculiar design of the building, the sewer pipe does not pass in the bathroom, but in the living room. These situations don’t happen often, but they do happen.

Another mistake that builders often make in the process of arranging a sewer pipe is the use of mounting foam as a sealing gasket. Do not forget that its main property is the dense filling of any space. As a result, it becomes an excellent conductor of vibration.

Noise Elimination Methods


If it turns out that the sewerage passes in the living room, then the most correct solution would be not to soundproof the pipes, but to transfer them. Such a solution to the problem can only be carried out at the construction stage. It will no longer be possible to perform the move after the completion of the work. It’s funny that this situation also occurs in new buildings due to miscalculations in the design. In practice, the drain pipe most often runs in the bathroom or toilet, if the bathroom. node is not aligned. Now directly about the methods.

Soundproofing a toilet in a private low-rise building or in an apartment as a whole can be performed through the following operations.

  • Installation of silent pipes.
  • Fixing soundproofing materials.
  • Installation of rigid clamps, in order to make the sewerage structure more static.
  • Box installation.
  • Pipe installation or repair.
Photo: sewer pipe fixed with a clamp

Silent pipes

Silent pipes can be called a novelty in the building materials market. They are not yet used so often, but they are successfully gaining recognition among buyers. Distinctive features of such a riser are a thickened wall and special components that are designed to prevent the penetration of sound and vibration into the room. It is noteworthy that silent pipes extinguish even infrasound.

In addition to such positive qualities of the new material, there are a couple of significant drawbacks. The prices for such pipes are much higher in comparison with the classic version of PVC. Also, they do not differ in a long service life, no more than 30 years. Of course, you can find more resistant options, but the price will increase in progression.

Fan pipes

At its core, this is ventilation for sewers. In a private house, the height of which does not exceed two floors, the installation of fan pipes is not carried out, and there really is no need for this. The legislation does not require this either. In relation to multi-storey buildings, the presence of a fan pipe is mandatory. It allows not only to equalize the pressure in the riser, but also accumulated gases are discharged into the atmosphere through it, which can cause airborne noise.

A function similar to fan pipes, but indoors, can be performed by air valves. Their purpose is to let air into the sewer and at the same time prevent reverse movement. You can make soundproofing for air ducts with soundproofing materials, but so as not to block the duct. If the capacity is disturbed, water from the riser can be directed through the inlet.


In practice, the most common situation is when the sewerage system is already installed and its replacement will lead to unnecessary financial and labor costs. Thus, residents of apartments who have a need to reduce the noise level from the riser resort to the use of various kinds of soundproofing materials. As such, many options can be used.

The implementation of sound insulation of the sewer riser does not require special skills, it is enough to have at least a little experience in installation work. The easiest way to do this is through the use of foamed polyethylene or polyurethane foam.

As for the places where the riser passes through the floors of the building, as mentioned earlier, you should not use mounting foam, since it only enhances structural noise. Instead, you should take porous rubber. This will minimize the possibility of transmission of vibration to the building structure and eliminate the acoustic effect.

On a note. The type of sewer riser in soundproofing is not presentable enough. Based on this, it makes sense to close the pipe with a decorative box. The design itself can be modified with various finishing materials.

Photo: Sewer pipes in a box

The box will not only create a more attractive appearance, but also give additional sound insulation. It is important to take into account the moment that it should not be made deaf. Access to the water supply is necessary, as it often passes in close proximity to the sewer. There is a chance that you won’t have to do anything else behind the box, but the likelihood of an emergency must be taken into account. It is then that ease of access and efficiency of work can significantly reduce the detrimental consequences of an unforeseen situation.



Among the materials that give the maximum effect can be used:

  • Foamed polyethylene.
Photo: polyethylene foam
  • Polyurethane foam.
  • Foam rubber.
Photo: foam rubber
  • Styrofoam shell.
  • Mineral wool.

Important. From the last option, namely from mineral wool, it would be more correct to refrain. She, of course, will fulfill her role, but is quite unsafe for the health of the household.

Photo: mineral wool

Soundproofing with your own hands


If there is a need to reduce the noise coming from the sewer, then you should try to do it yourself. The work is not difficult, but hired work will take decent money for it. Do-it-yourself soundproofing of a sewer riser with a high degree of probability will be no worse. The work algorithm is as follows:

  • The pipe is measured in order to determine the amount of soundproofing material that will have to be purchased. You need to measure the height of the pipe with a tape measure. Then, for example, a circle is determined by a thread. The resulting units must be multiplied. Add about 10-20% to the result.
  • Purchase of adhesive tape or clamps, and material.
Photo: polyurethane foam
  • Wrapping the pipe with soundproofing should be done so that the entire surface is covered. Then the material is fixed with adhesive tape (or clamps).
Photo: fastening soundproofing

Common Mistakes

Despite the simplicity of the operation, people often make certain mistakes. You should familiarize yourself with them in advance to avoid repetition:

  • Wrong choice of material. It is important not to confuse sound insulation with externally similar thermal insulation. If in doubt, it would be right to consult with the store employees.
  • The presence of air under the soundproofing. A loose fit of the material to the surface of the pipe will make all the work meaningless.

Summing up, it is worth noting that it is quite easy to get rid of the noise that occurs in the riser. It is important to correctly approach the performance of work and the selection of materials.


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