To prevent or stop sound from entering or leaving a room, soundproofing it is necessary in many circumstances. For example, you might live in an apartment complex and find you’re constantly dealing with noisy neighbors (or you might in fact be the noisy neighbor).
Or perhaps you’re currently renovating your property, and soundproofing is something that’s always been on your mind, just for convenience if nothing else.
Ultimately, soundproofing a room relies on four elements: mass, decoupling, absorption, and damping. This article doesn’t go into a lengthy explanation of these elements, but all of the techniques listed here use some combination of them.
If you want to do the best job possible, then use as many elements as you can, but remember that soundproofing isn’t a cheap project, so make sure you keep to any budget you’ve set.
How To Prevent Sound From Entering & Leaving A Room
Here are some of the most helpful ways to prevent sound from entering or leaving a room.
- Identify the room’s weak spots
- Soundproof the windows
- Soundproof the doors
- Soundproof the walls, floors and ceiling
- Soundproof air vents
- Seal gaps to prevent airborne sound leaks
- Use sound baffles, soundproof curtains, etc
Identify The Room’s Weak Spots
Every room has weak spots when it comes to sound entering or leaving, and these are usually areas that have gaps.
The most obvious weak spots in a room are windows and doors, but floors can also be a weak spot if not properly fitted.
One of the less obvious weak spots are the joins between drywall, and this should be one of the first to address if you’re renovating a room.
Windows
If you’re looking for the ultimate way to prevent sound from entering or leaving through windows, then the best step is to remove them entirely and fill the gap with drywall. However, this isn’t always an option, particularly if you want natural light in the room, so try these following tips:
- If you don’t have them already, consider upgrading your windows to UPVC. UPVC has much better sound absorption properties than glass, and although they were designed to provide better heat insulation, much of the same logic is applied to sound insulation too.
- If you can’t afford UPVC, then make sure you have double-glazed windows. These consist of two panes of glass with an air space in the middle, which gives another layer for the sound to pass through.
- One of the most important steps is to seal any cracks around the window frame with acoustic sealant. Gaps and cracks are one of the primary sources of noise pollution, and are often overlooked when soundproofing a room. Acoustic sealant differs from normal caulk because it remains flexible, and so is less likely to warp or crack over time.
Read my article on soundproofing windows which covers various techniques for the same.
Doors
Unlike windows, which can ultimately be removed from a room if you’re serious about soundproofing, you’ll always need at least one door. This makes them a serious weak spot when it comes to preventing sound from entering or leaving a room, and it means you have to get more creative with how you do this.
It’s almost impossible to use soundproofing techniques such as decoupling when soundproofing a door because you’re limited by its function. After all, a door still needs to open and close. Instead, you’ll have to rely on the principle of mass, and just install a very heavy door. The heavier the door, the more sound it’ll absorb.
It’s also worth thinking about the material the door is made from. The same logic applies here, as denser materials will absorb more sound. Metal will absorb more than wood, but is obviously heavier and more expensive.
Doors designed for the purpose do exist, but they’re expensive and don’t add more than what you can do on your own.
Regardless of what kind of door you have fitted, you’ll have much greater success addressing the gaps around it.
Noise pollution can enter and escape through the gaps around a door, and also through gaps around the door frame. Take care of any gaps or cracks using acoustic sealant, but doorjambs require more work.
There are different options available for this job. You can buy acoustic sealant tape, which simply fills the gap, or you can use a more permanent method.
Mounted door seals are more expensive, but also do a much better job of blocking noise pollution. They’re really easy to buy online, but it will mean installing it yourself.
Read my article on soundproofing doors which covers various techniques for the same.
Soundproofing Walls, Floors, And Ceilings
Once you’ve identified and treated the major weak spots in a room then it’s time to address the bigger spaces. Walls and ceilings can be soundproofed in much the same way, whereas floors require slightly different methods.
For walls and ceilings, you simply need to add more mass. The easiest way to do this is to add another layer of drywall, and make sure there’s plenty of insulation between the two layers.
The more drywall you add, the more mass there is, and therefore more sound will be prevented from entering or leaving the room.
If you’re going to the trouble of adding more layers of drywall, make sure you use decoupling mounts. This basically means fitting the two layers of drywall on their own mounts, as this prevents sound waves from vibrating through the wall.
It’s also worth using a product such as Green Glue, which is a product specifically designed for soundproofing projects.
You layer Green Glue (see image below) onto the inside of the wall and it turns sound waves into heat. This helps with damping sound, and drastically improves the effectiveness of any soundproofing project. Read my detailed article on Green Glue.
After installing drywall, make sure you seal the gaps between panels with acoustic sealant, much the same as with the windows and doors.
When it comes to soundproofing floors, adding more mass isn’t always that easy.
Unlike with drywall, you might not want to cover up the existing flooring. However, if you’re willing to rip up flooring then adding a layer of insulation will make a big difference to noise pollution.
If you don’t want to make such permanent adjustments, putting down heavy carpets or rugs will make a difference, just not a very big one.
Soundproofing Air Vents
One of the more overlooked areas of a room when it comes to soundproofing is air vents.
HVAC systems can be a major source of noise pollution as sound waves have quite an easy time travelling through the open spaces. This, combined with the fact that HVAC systems lead outside, and the main materials used, make them a big problem when it comes to sound leakage.
So how do you prevent sound from entering or escaping through a HVAC system?
Use Flexible Pipes
Standard HVC systems often use rigid metal ducts, and these allow sound waves to bounce and echo easily. However, if you replace them with flexible ducts, sound will have a much harder time travelling along them. Also, the more flexible materials often do a better job of damping sound.
Read my guide on soundproofing air vents.
Seal Up Any Gaps
Just like with any other part of the room, sealing gaps around HVAC vents is a good place to start.
Due to the way the systems work, it’s not uncommon for vibrations to travel along the HVAC system, and the effect of this can be lessened through acoustic sealant. Applying it around the vents will stop any vibrations passing into the wall.
Install Soundproofing Composite
Soundproofing composites are effectively just very dense materials, and so absorb any noise pollution that passes through them.
It can be helpful to line the vents with these materials if you can, as this will mean less noise pollution will make it through the ducts.
Sound Baffles
A sound baffle is designed to prevent any sound that enters it from escaping. It does this using its maze-like structure, which traps sound waves.
Installing one of these on the HVAC duct will stop noise from entering or exiting the vent, but it might not look particularly attractive.
Other Options
While the suggestions here are extensive and cover most aspects of a room that need soundproofing, there are some other methods that haven’t been covered yet. These methods are lower down on the scale of effectiveness, but certainly worth a try, especially if you’re on a budget.
Soundproof Curtains
Although you can buy special soundproof curtains, these can be quite expensive. A more cost-effective option is to simply use some heavy drapes.
Again, this is based on adding more mass to disrupt sound waves, so the heavier the better. Velvet drapes do a particularly good job of this.
Read my buying guide on soundproof curtains.
Weather Stripping
These are designed to improve heat insulation, but they work just as well for sound pollution.
Weather stripping is meant for external doors and windows, but there’s no harm in installing them on internal doors too. They work much like the door seals mentioned earlier in that they fill the gap around the door or window.
Conclusion
The easiest way to prevent sound from entering or leaving a room is to seal any gaps. Doing this can take time, but is well worth it. However, the more money you’re willing to spend on a project, the better a job you’ll do.
Just remember though, egg cartons and acoustic foam aren’t effective methods of soundproofing a room.
Check out my recommended products for soundproofing. Also, if you liked this article, don’t forget to share it.
Also read: how to reduce traffic noise from a balcony