How to Tell if an Apartment Is Soundproof? An Expert Analysis

Getting an apartment or condo instead of purchasing a house seems to be the most befitting for most city folk. While apartments are a great choice, they come with one major downside: noise coming from everywhere!

Apartments are usually not soundproof and being sandwiched between other residencies further escalates the issue. To live peacefully in such a place, you need to make sure that the space is soundproof before renting or buying.

And if you’re wondering how to tell if an apartment is soundproof, look for some apparent signs of soundproofing such as:

  • Windows and doors with plugs, double panes, and seals installed
  • Thicker walls
  • Use of any soundproofing product such as curtains, acoustic panels, or foam

With furnished ones, it gets a lot easier to tell if an apartment is soundproof or not. Typical signs are thick carpets and curtains or heavier or more cushiony furniture.

This detailed guide explains all that you need to know about the right execution of these mechanisms.

Construction Material Used in the Apartment  

Sound energy can easily pass through most of the construction materials used these days. Different materials allow different levels of sound/noise from outside to enter.  

For instance, thick concrete in the ceilings, walls, and floors will reduce impact noise from above, below, and sides of the apartment. Whereas bricks restrict the passage of airborne noise through the walls.

Typically, older apartment buildings are a bit more solid in their construction as compared to the newer ones. New constructions do well from the construction standpoint but allow a lot of noise to pass through from the outside.  

Most of the new constructions have no insulation put between the side to side walls of the apartment. They’re supposed to be separated with blocks of concrete masonry, bricklayers, or concrete that have an STC rating of around 53. If such construction materials are used, they will diffuse noise over a wide range of frequencies and will effectively keep noise out or in. 

Thus, it’s wise to take a look at the way apartment buildings are typically constructed in an area. If you see a lot of concrete, insulation, and cavity-free structuring, go for it! 

Check the Floors of the Apartment

Almost all apartment buildings are multistory, you’d have people living on all your sides. Make sure you check all the floors to see if they can block impact noise, which is pretty common in such buildings. Apartments primarily made of wood often transmit a great deal of noise through the floor. 

Look for two things in particular; underlayment and floor joists.


A thin layer of insulating material, called an underlayment, is laid before the final layer of floor material. Made of materials such as felt, fiber, foam, or rubber, the underlayment provides excellent sound absorption, insulation, and cushioning.  

Underlayment is particularly essential if the apartment has floating floors. It provides the much-needed support, stability, locking system support, and noise reduction to the floor. Not to mention, it also provides an even distribution of laminate across the subfloor and has a waterproof barrier for added durability.

The underlayment can also be incorporated into the floor years after it has been constructed, usually under the carpet, tile, or wood flooring.  The mass and density they add to the floor will credibly reduce footfall impact noise.

Floor Joists

Floor joist isolators are used to eliminate the transmission of vibrations caused by sound energy. They prevent impact noise from traveling through the building structure. The U-shaped design offers additional support to the floor frame. 

Floor joists are usually made of medium density thermoplastic that is a remarkable sound isolation material. You’ll find them either nailed, glued, or screwed into the wood for stiffness of the subfloor sheathing.

When these floor joists decouple the floors from the rest of the building foundation, they block noise from entering and exiting it. Floor joists are clearly visible and you can easily detect them.  

If it’s a carpeted apartment, make sure they are tightly woven and heavy so they can absorb sound and reflections. Carpets don’t only add to the aesthetic beauty of the apartment but are also a great way to soundproof it.

You can look for any rubber floor mats or foam under the carpets if you’re still concerned that they will transmit sound. Adding foam or rubber under carpets provides another insulating layer to block sound. 

How to Be Sure That an Apartment Is Soundproof? Knock Knock!

You can only know if an apartment is soundproof on your first, second, or third visit if there is noise outside. What if you can’t schedule the visit at the time of the day when it’s noisy outside? Here’s another way!  

You can tell if the walls are soundproof simply by knocking on them. If the walls have dense mass, you’d clearly know even if you’re not too familiar with sounds. You’ll easily be able to tell if they are hollow or filled with some material.  

Thick, concrete, brick, or stone walls are perfect for blocking sound. When you knock on a solid wall, it vibrates at a very low rate because it is thick and has more mass per square inch of surface area compared to a hollow wall.  

Other than that, if you see walls with mass-loaded vinyl, or sheeting with gluing (green glue), know that it is a well-soundproofed apartment. The more massive a surface is, the more energy it requires to create a vibration.

Windows and Glass Doors 

Pay special attention to windows and glass doors, if the apartment has them. If, after checking the floors and the walls, you still don’t know how to be sure that an apartment is soundproof, check the windows.

Glass windows and doors are the biggest entry points for noise (especially airborne noise), light, and air in an apartment. They must be strong and tightly sealed to keep all three out. 

There are three common ways of soundproofing windows. Keep an eye out for these as well! 

1. Double or Triple Glazing

Double and triple-pane windows have spaces between the panes to trap/block noise. The dual panels act as a sound barrier and are an essential part of soundproofing a space. If there is no double glazing, you should ask if there’s any specific permit or requirement to install them.  

Double and triple-paned windows will stop almost 95% of the noise from coming in as compared to single-paned windows or doors. A conventional single-pane window stands with a 28 STC rating, while a soundproof window will have around 45 to 50 STC.  

2. Weather Stripping

If you see weather stripping on doors and windows, know that the apartment is soundproof. Weatherstrips are used to seal these openings and prevent wind, rain, and water from leaking in.  

While doing so, they also help in keeping sound out of the room. You may see felt around the window sash, which is a great insulator as it acts as a seal against airborne noise in the compressed form.

Moreover, you can also point out V Strips in an apartment. They are originally designed to stop moisture from coming inside a room, but they are also great at keeping noise out. These plastic V strips close gaps in windows to keep water and air out.

Insulation Foam can also be found stuck on some doors and windows.  

3. Window Plugs

Window plugs are made from any soundproofing mat layer stuck to a wooden board. They are easy to detect because of their unpleasant appearance killing the room’s aesthetics.  

They will not only block light from entering the room but they are also excellent at soundproofing. 

Position of the Apartment

The position of the apartment you’re planning to get has a crucial role in the kind and amount of noise you’ll be dealing with. Before you buy or rent a space, see if it’s placed in the middle, top, or below other apartments. Its position will determine the level of soundproofing needed. 

For instance, if you get an apartment located in the middle of the building, there would be no escape from sound whatsoever. You’ll have neighbors right, left, above, and below you. The amount of soundproofing material required to block the noise out of such apartments would be way higher than for an apartment on the top floor.  

By keeping the position in mind, you can better comprehend if the apartment has sufficient soundproofing. For instance, if the apartment faces a main city road or a busy street, make sure the windows or doors that open to that side are properly sealed.

Some Important Questions to Ask

These are some of the most important questions you should ask the dealer or owners of the apartment. Their answers should help you decide better whether the apartment is soundproof enough for your needs and if not how much would it cost you to soundproof it.

What kind of people live around the aparment? 

This is an important factor to consider when deciding on an apartment located in a multistory building. You can ask the society head, property manager, or anybody who’d have the knowledge of age, occupations, and activities of people in the building.  

You can specifically ask if the building has more retired persons living, or are students and bachelors renting it? How many families live there? Do they have young kids?  

The majority of a single type of people will tell you how noisy or quiet it’s going to get. You cannot control activities and noises from other people around you, but you have the liberty to choose! So, ask around.

Is the apartment building designed to convert into a condo? 

Ask the management if they have engineered the place to be converted into a condo at some point in its life. If yes, there must have been some involvement of an acoustic professional in the design and architecture of the place.  

Asking this would tell you if you need to invest in soundproofing further or if the apartment is already appropriately soundproofed.  

What about plumbing in the apartment? 

Oftentimes, newer buildings are built with plumbing that runs along corridor walls. Ask where the main plumbing lines are running from and to.  

You will also probably be able to hear water running from the corridor. Also, you can expect to hear the same amount of noise from the neighbor’s plumbing, as well. 


These were some of the basic tips on how to find out if an apartment is soundproof or not. Noise pollution can cause serious issues to your peace and tranquility. This is why when you’re apartment hunting, you need to make sure you get the one that’s soundproof.

To summarize it all, the main signs of a soundproof apartment include acoustic foams, thick walls, double glazed windows, insulated structure, and door seals.