How to Build a Soundproof Box for a Generator in 8 Simple Steps

How to Build a Soundproof Box for a Generator

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We live in a place where natural disasters are not unknown, and they often lead to power outages.

Gas generators are set to hit an incredible mark of $9 billion by 2025.

Well, now, no one likes to be left in dark, is it right? And for that reason, power generators might come in very handy to us.

They are often used during and after power outages, while we are waiting for everything to get back on its feet again.


Subsequently, another inconvenience might show up. Generators can be very loud.

Just imagine the situation:

A natural catastrophe occurs; there is an almost inevitable power outage; you are already frustrated and irritated enough, but you have remembered that you have a power generator in your house; so you find it, turn it on, and it starts buzzing like crazy.

Not very convenient now, is it?

Well, there are a few things that you can do – and one of them is a homemade generator quiet box.

First resolution to a buzzing power generator is buying a soundproof box for your generator. Alas, these generator quiet boxes are very expensive.

Yet, there is another resolution that I will be telling you about today. And that resolution is building your own soundproof box for a generator.

So, let’s begin from the scratch, and as the time you reach the end of this article, you’ll know exactly how to build a sound proof box for your generator that will provide all sorts of benefits.

How to Build a Soundproof Box for a Generator

How to Build a Soundproof Box for a Generator

What You'll Be Needing:

MDF - Medium Density Fiberboard
This will serve as your main material for the box
MLV - Mass Loaded Vinyl
The first layer that you will want to add to your soundproof generator box
Foam mats
An additional layer that always comes in handy when soundproofing anything
Green glue
A soundproofing material that can also be used for gluing the edges
Ventilation duct
Provides nice airflow and supply for your generator box
BlocknZorbe Sound Panels
Can substitute instead of MLV + foam (great outdoors!)

Please keep in mind that it is impossible to completely mute the generator. It needs a lot of air, and it needs some vents.

If you do not want it to overheat (and, believe me, you do not), then you need to put some vents on your soundproof box.

And holes make a space for sound and buzz of a working generator to get out.

1. Taking some measurements

You will be making a silent generator box, and one thing that you need to know is that generators come in different sizes, and not all generator boxes are of the same size, obviously.

Accordingly, the first step that you will have to make when it comes to constructing a soundproof generator quiet box on your own is measuring the very generator.

Pay attention to the measures. This is very important. If you mess up the measures, you will probably not have enough space to build the rest of the box.


There is a nice proverb that says: Think twice, cut once. So measure twice (even thrice!), before you start cutting.

Once you have taken the correct measures, write them down, and remember to add a few more inches on all sides, because you will need some space for insulation thickness and vents.

When you have measured everything and added that few inches on all sides equally for the thickness of soundproofing, write the final measures down, and we can start the work on your generator noise reduction enclosure.

2. Cutting the Box Out

You have your measures written down, you have your fiberboard of medium density prepared, and you are ready to start cutting now.

Of course, it is not strictly necessary to use medium density fiberboards, but it sure helps.

And since you’ll be making noise cancelling generator box, you better learn which materials provide the best noise cancelling results.

You can use the regular plywood if you can’t find anything else, or if you have some spare plywood left lying around in your garage, but it can be a little bit less effective than the fiberboard that I have mentioned previously.

I had a look at some fiberboards for your convenience, and I would warmly recommend these.

Use your pencil and that right angle ruler to label the measurements on the fiberboard, and when you are sure that everything is done right, you can start the cutting.

Use your table saw or circular saw, whichever you have on your hand, and pay attention to the measurements and labels on the fiberboard that you have made previously.

Now, when this part of the work is done, we can proceed to the next step.

How to Build a Soundproof Box for a Generator

3. Setting some ventilation holes

Let’s assume that you have already prepared everything and that you have your ventilation duct on your hand.

Take that ventilation duct and measure its diameter.

Now mark some circles on the fiberboard.

Two marks for the ventilation duct should be placed like this:

  • 1
    1st one should be placed on the top piece of fiberboard; keep in mind that it would be much better if you placed it a bit more to one side, rather than in the center of the board;
  • 2
    2nd one should be laced on a board that will be used as a wall, and that will be placed on the opposite side from the top hole

When you have marked everything to the instructions, lay your fiberboard “walls” on the table, placing the “ceiling” one in the center, and with the rest surrounding it.

Another great thing about ventilation holes is that they will help you as places to hold the box, creating a portable generator soundproofing you can take from one to another generator.

4. Adding the Mass Loaded Vinyl Insulation

The first rule to soundproofing is layers. Layers of materials, layers of free space and sound gaps, layers of all types.

These layers of free space will make some room for the sound to scatter.

Therefore, sound insulation for generator is important, since we all know how loud generators can get.

Best materials to use are materials that are made with the same “philosophy”, layers of spaces and materials.

Mass Loaded Vinyl

One of these types of materials is mass loaded vinyl that I have mentioned at the beginning.

Remember it well; you will be needing it a lot.

Whether it is soundproofing a wall that you share with loud neighbors, or the ceiling of your own apartment, it is sure something that we always come back to when it comes to soundproofing.

This will be the first layer that you will want to add to your soundproof generator box.

Label the measures of your generator quiet box, and cut the mass loaded vinyl to the size of it, and glue it down directly to the inside side of your soundboards.

We like to use the smaller, workable MLV sheets from Second Skin Audio for our generator boxes.

It’s a little bit more per square foot, but you’ll save money by not having a bunch of leftovers.

5. Caulking that first layer you made

Edges can be a little bit difficult to glue down properly, and for them not to come off.

Green glue is very good for this purpose. And not to mention that it is acoustic! Killing two birds with one stone.

Of course, if you have some regular caulk, it is okay too, but same as plywood and fiberboards, it wouldn’t be as efficient.

6. Gluing the foam mat on

As I already mentioned, layers!

Foam mat will help you with your generator enclosure DIY that will drastically reduce the noise.

Another layer that you will be adding on the “walls” and “ceiling” of your soundproof box is made of foam mats.

Foam mats are very soft, so they would make it hard for the sound to jump around and bounce off of the “walls” of your DIY generator enclosure, and in that way, they will reduce the noise.

Also, they present an additional layer that always comes in handy when we are soundproofing anything.

You know how when it is cold outside, you put on some more layers of clothes?

Well, it is all the same when it comes to soundproofing generator noise.

Once more, take the mats you have and label the measurements of your “walls” and “ceiling” and cut them according to the sizes taken before.

Glue the mats down directly to the vinyl layer, and repeat the same with the edges and acoustic Green Glue caulk

This will be a fine touch to the inside of your soundproof generator box.

7. Putting the box together

And now the time has come to collect all of the pieces, and put together your enclosure!

Assemble the “walls” around the “ceiling” and attach them to one another by nails and screws.

Another thing that you can do to make sure that you will have an easy access to your generator, is installing some hinges.

Keep in mind that you will need to readjust the vent hose in that case, but it is just a small adjustment to make, and much better accessibility to the thing that you need so much.

You might also like: Review of the Quietest Impact Drivers

8. Installing the venting duct

As I mentioned at the very beginning, undisrupted “breathing” of your generator is of high importance when it comes to the well-being and proper functioning of your generator.

In that light, you will have to provide it with a nice airflow and supply.

If it doesn’t have enough air, it can start overheating, and heat to the instances where it can make a potential catastrophe.

Therefore, even when you soundproof portable generator, the same rules apply – and you should always think of ventilation and heat dispersion.

The process of combustion is not attainable, and risk is very high. And we don’t want that for your generator.

best quiet inverter generators

Once you have installed vents on your DIY generator enclosure, use a lot of venting duct that I have mentioned earlier. Be sure to use a lot of it. The more, the merrier.

Here is a quick lesson: sound waves have a straight linear path when they are traveling.

If you use a lot of bends when placing your venting duct, a lot of noise will get caught and lost in its wrinkles.

Place the hoses into those holes that you have prepared in the 3rd step, and make sure to tighten them in place. You do not want them jumping around.

The final touch would be adding a little vent right above those openings, and your soundproof generator box is ready to go!

On Building a Soundproof Box for the Generator

As I promised, it wasn’t hard at all.

Commercial generator noise reduction enclosure is one of the most commonly purchased products along with the generator – however, it’s not really hard to make one yourself.

And it was sure fun to do a little project on your own, and save a few bucks on the way, wasn’t it.

And when there is a power outage next time, you will not be nervous for the additional unpleasant buzz of your generator.

You will be able to just turn it on, and forget that you ever have.

You might also like: How to Make a Generator Quieter

I want to soundproof my generator box

How to Build a Soundproof Box for a Generator

How to Build a Soundproof Box for a Generator

Generators are a lifesaver but sometimes they can be too noisy and disrupt the peace. Here's how to build a soundproof box for a generator for a quiet time.

Active Time 1 hour
Total Time 1 hour


  • MDF - Medium Density Fiberboard
  • MLV - Mass Loaded Vinyl
  • Foam mats
  • Green glue
  • Ventilation duct


  1. Taking Some Measurements
  2. Cutting the Box Out
  3. Setting Some Ventilation Holes
  4. Adding the Mass Loaded Vinyl Insulation
  5. Caulking That First Layer You Made
  6. Gluing The Foam Mat On
  7. Putting The Box Together
  8. Installing The Venting Duct
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