How To Soundproof A Townhouse (Including Basement)


How To Soundproof A Townhouse

Townhouses are generally wonderful buildings to live in, particularly the older ones. However, what’s not so lovely about living in a townhouse is the amount of noise pollution coming through the shared walls.

Luckily, there are plenty of things you can do to soundproof a townhouse. This article looks at the easiest and most effective ways to soundproof a townhouse, including soundproofing methods specifically for the basement.

What to do Before Soundproofing a Townhouse

The most obvious place to start with any soundproofing project is to identify the source and location of any noise pollution you’re looking to cut out. The most likely location is any shared walls in the house, but if you live in a basement apartment then much of the sound is probably coming from above you.

  1. If there are any shared doors between the houses (much more common in older builds), this will be the best place to start. While these doors might have served a purpose in the past, it’s unlikely you and your neighbor are needing to pop into each other’s houses too often.
  2. Another prime source for noise pollution is shared HVAC vents. It’s likely that several, if not all, the townhouses in your development are linked to the same HVAC system, and these can be a big culprit for noise travelling between properties.
  3. Finally, there are the walls. This will be the biggest amount of work, but also one of the most straightforward to solve. If you live in an old townhouse, the walls are probably quite solid, but newer, potentially divided properties might only have some stud wall put up to separate rooms. Whichever you have in your townhouse, make sure you know what you’re working with.

When it comes to basements, much of this same logic applies. The only other area you’ll want to look at is the ceiling, particularly if you have neighbors living above you. However, many of the principles you’d apply to soundproofing a townhouse wall will also work on a basement ceiling.

So these are the most common sources of unwanted noise in a townhouse. Of course windows are a big problem too, but short of taking them out and bricking them up, there’s little you can do about this. Windows are a constant thorn in the side of any avid soundproofer.

How to Soundproof a Townhouse

1. Soundproof the HVAC System

Let’s start with soundproofing the HVAC system, as this is one of the easiest to solve and will easily make a big difference to the amount of sound pollution making it into your home.

The most effective solution is to either completely remove the vent, or rip it out and reposition it somewhere else, ideally in a different room. However, this is a pretty extreme and expensive solution, and most people probably aren’t willing to gut their home just to remove an air vent. So failing that, try one of these methods.

Install a Sound Maze

Building a sound maze inside the air vent really isn’t that difficult, and short of blocking the vent entirely, this is probably the most effective method. This is what it looks like:

The best product to use in this situation is acoustic foam, which is designed for sound treatment rather than sound blocking. However, the main focus here is to reduce echo, so this is ideal.

Look out for acoustic foam that’s as thin as possible. Don’t use the same stuff you’d use on a normal wall, as this will be far too thick, and you still want there to be enough air flowing through the vent. Along with this acoustic foam, you’ll need some MDF or plywood, glue, and tools.

To build a sound maze, follow these steps:

  1. Measure your boards. These need to be as tall as your air vent but narrower so that air can still pass through. Cut one out of wood, check it fits, and then use this as your guide for the others. How many you need will depend on the size of your vent.
  2. Once you’ve got your boards, stick acoustic foam to one side of them. You can do this with normal glue, but Green Glue, which is an acoustic sealant, will help make them more effective.
  3. Next, stick the boards in the vent. Start as far down as you can, sticking the board to one side. Stick the next to the opposite side so you’re creating a zig-zag pattern.
  4. Position each of your boards a few inches away from each other, and you’re done.

Fit a Soundproof Curtain

This is a much easier and less invasive method, but won’t be as effective, and will also affect air flow into the room. All you need to do for this is buy a soundproof curtain, cut it to size, and hang it in front of the vent. You can also do this with a soundproof blanket or sheet, which might be easier so you can cut it to size.

Check out my guide to choosing soundproof curtains if you are considering this option.

The Doors

Once you’ve taken a look at the air vents in your townhouse, the next step will be to tackle any doors, as these are another prime area of noise pollution.

The most effective option will be to remove the door and fill the hole with drywall. If it’s a door with no purpose, this is ideal, but if the door needs to stay then try one of these methods.

Install a Solid Core Door

Most normal doors are hollow, making them ideal for sound transference. Getting a solid core door will do a much better job, but be aware one will set you back at least $500, but it can be even more for a top-of-the-line one. This is an expensive option, but will definitely be very effective.

Modify the Existing Door

The least invasive and cheapest option is to modify the existing door. First, consider hanging soundproof curtains in front of the door, or at least heavy drapes. This will help in absorbing some of the noise pollution.

Next, address the gaps around the door. This is best done with an acoustic sealant, like Green Glue, but this will obviously make the door unusable. The next option is to use weatherstrip tape, which is meant for heat insulation, but does the same job with sound.

This product is really easy to buy online and in hardware stores and simply fills in the gap around the door, making it more snug. Be sure to address the larger gap at the bottom with some kind of door sweep, such as this one. Again, these are designed for heat insulation, but do a good job at keeping out sound.

Check out my soundproofing guide for doors.

The Walls

Soundproofing townhouse walls will probably be the biggest job, so be sure to tackle the smaller ones first because you might find that they reduce noise pollution enough. When it comes to the walls, the same principles apply as with other walls: add more mass.

It’s likely that the townhouse walls are solid brick rather than stud and plasterboard, so decoupling won’t be helpful here. Either add more drywall (but you’ll need quite a bit) or stick up some mass loaded vinyl. This is great at absorbing sound, and will be even more effective if you can convince your neighbor to do the same in their house.

Whichever way you decide to add mass, make sure you use plenty acoustic sealant. This will help fill in gaps and make your solution much more effective.

If you can’t get away with something as invasive as adding more drywall, then try hanging some really heavy drapes on the wall. This won’t do much, but will at least offer some reduction to noise pollution. Whatever you do, don’t fall for the egg box trick. Sticking egg boxes to your wall really does nothing.

Soundproofing a Townhouse Basement

All of the solutions mentioned above can be applied to a basement, and will be just as effective. However, in a basement, it’s also necessary to address the ceiling, as this will be the biggest source of unwanted noise (particularly if your neighbors have hardwood floors).

The most effective solution is to tear down the original ceiling, fill the void with dense acoustic insulation, and then re-fit the ceiling. Adding another layer of drywall onto the existing ceiling will also help to add more mass.

If re-fitting a ceiling in a basement, try to hang it using decoupling methods so that sound can’t vibrate through the joists into the ceiling. The most important thing is to reduce the vibrations travelling into the basement, as impact noise will be the biggest problem.

Along with that, just add as much mass to the walls as you can. Laying carpet will help with echo and reverberation, which impacts overall noise levels in the basement. However, the ceiling is likely going to be the main source of noise pollution, so this is the most important one to address.

Conclusion

There are many ways to soundproof a townhouse, and they’re no different from soundproofing any other property. However, the biggest difference is that you only need to tackle shared walls, floors, and ceilings, as it’s likely you only want to cut out your neighbor’s noise.

A final piece of advice is to see if your neighbors want to get involved in the project, as any soundproofing will be much more effective if you both do it.

Thanks for reading! Before you go, check out my recommended products for soundproofing.

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