How to Build a Soundproof Generator Box (8 Steps DIY Guide)

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Is your generator making a shit ton of noise and are you looking to soundproof the generator then building a soundproof box is the only solution. We have been getting a lot of requests from the readers to write an article on How to Build a Soundproof Generator Box, Completely DIY (Do It Yourself). So I experimented and tried multiple generator boxes and came up with this one. This is an easy and simple one. Just follow our steps properly and you can build your own Soundproof Generator Box.

How to Build Soundproof Generator Box

Steps to Build a Soundproof Generator Box are

Step 1: Measure the Generator Size

Step 2: Cut the Box Out According to the Measurement Taken

Step 3: Set Up Ventilation Holes on the box

Step 4: Add the Mass Loaded Vinyl Insulation

Step 5: Caulk the first layer using Green Glue Compound

Step 6: Glue the Foam Mat on the box

Step 7: Put the Box Together

Step 8: Installing the Venting Duct

Products Required Before Building the Soundproof Box for Generator

Product NamePurpose 
Foam MatsWe can use this foam mats to add an additional layer to box for more soundproofing or sound deadening
MDF - Medium Density FiberboardThis will be used to make the box
Mass Loaded VinylMass Loaded Vinyl will be used as the first layer of soundproof for the box.
Green Glue CompoundGreen Glue Compound is a Soundproofing material which can be used for gluing the edges and also to glue the second layer.
Ventilation DuctVentilation Duct is used to provide proper airflow for the generator box.

Tools Required For Building the Soundproof Box for Generator

  • A Measuring Tape
  • Right Angle Ruler
  • Paper and Pen/Pencil (To Note down the Measurement)
  • Glue
  • Screws and Nails
  • Hammer and Screwdriver
  • Cutting Saw (Circular or Table)

How to Build a Soundproof Generator Box (8 Steps DIY Guide)

Step 1: Measure the Generator Size

Generators come in different sizes so we need to build one according to the size of our generator. So the first size is to measure your generator properly before moving on to the next step.

Make sure the measurements are very accurate and precise because the measurement is very important to build a soundproof generator box. If you mess up with the measurement then after building the box the generator might not fit properly and it will totally ruin all the hard work put in to build the box.

After taking down the measurement make sure you write the measurements in the paper or book. You might wanna add in a couple or some extra inches to make enough size soundproofing box. You might also require some space for insulation and vents for ventilation. After writing down the measurements then follow step 2. 

Step 2: Cut the Box Out According to the Measurement Taken

After writing down the measurements of the generator, you need to cut the box down according to the measure. As I suggested before you can use a Medium Density Fiberboard (Its available on Amazon). You can also use regular plywood but for best result use this Medium Density Fiberboard.

Use the pen or pencil and that right angle ruler to label the measurement on the fiberboard, after making sure that everything is right then you can go ahead and start the cutting process. 

You can use any type of cutting saw such as a table saw or a circular saw whichever you have available with you. Now cut according to the measure of each section of the box.

 Step 3: Set Up Ventilation Holes on the box

After cutting the box down according to the exact measurement, you need to set up some holes for ventilation for the box. Make sure you have brought the ventilation duct before setting up the ventilation holes on the box. Now that you have the ventilation duct follow these steps.

  1. Take the ventilation duct and measure its diameter.
  2. Now mark two circles on the fiberboard using the measurement of the diameter of the ventilation duct. 
  3. Mark the circles as per this tutorial,
  4. The First Circle should be placed on the top piece of the fiberboard. Make sure that it would be very much better if you place the hole a bit more to one side, rather than in the center of the fiberboard.
  5. The Second Circle should be placed on the board which will be facing as the wall. This is the piece that will be placed on the opposite side of the top hole. 
  6. Now that you have marked everything on the board as per the instruction, lay the fiberboard walls on the table and place the ceiling of the board in the center and the rest of the board surrounding it. 

Step 4: Add the Mass Loaded Vinyl Insulation

Now that you have marked the ventilation holes on the fiberboard its time to create layers on the box. The first rule of soundproofing is to create as many layers possible. Now we are using the Mass Loaded Vinyl insulation to create the first layer so that the box is well soundproofed. 

These layers on the box will make the sound signal scatter making its soundproofing.

One of the best sound deadening materials that are available in the market is Mass Loaded Vinyl, which is what we are gonna be using in creating the first layer of the box.

Steps to Add the Mass Loaded Vinyl Insulation on the Generator Quiet Box

  1. Buy sufficient Mass Loaded Vinyl, which can also be used later for soundproofing other stuff at home. 
  2. Measure the Quiet Box and write down the measurement. 
  3. Mark the measurement on the Mass Loaded Vinyl. 
  4. Cut down on the markings of the mass loaded vinyl. 
  5. Glue it down directly on the fiberboard accurately using the Green Glue Compound

Step 5: Caulk the first layer using Green Glue Compound

Now that you have added the first layer to box which is the Mass Loaded Vinyl, now you need to caulk the edges of the first layer using the Green Glue Compound. Because adding the mass loaded vinyl on the edges can be very tricky, so you definitely need to add caulk the edges using a soundproofing material called Green Glue Compound.

Green Glue Compound is the best soundproofing material. It is a type of glue that is also sound deadening. When the sound signals hit on the green glue compound, the sound signal changes into heat energy making it sound deadening. 

Use the glue on the edges of the first layer and let it dry well before moving onto the next step. 

Step 6: Glue the Foam Mat on the box

Now that you have glued the edges of the box using the green glue compound, it’s not time to create a second layer to the box. Remember that layers are important in soundproofing anything. 

Now for the second layer, we are going to use an Acoustic Foam Mat which will absorb the sound signals. If you are wondering what is the best acoustic foam then check our article on Best Acoustic Foam Panel which we have already written on our blog. These acoustic foam mat or panels are very soft in nature so it will make the sound bounce off and not let it escape outside making the generator box very quiet and acoustic. 

To Install the Foam Mat on the box follow these steps,

  1. You need to get Foam Mat to start this process, so order some online.
  2. Measure the quiet generator box and write down the measurement.
  3. Cut the foam mat according to the measurement.
  4. Now glue the foam mat on the box above the Mass Loaded Vinyl as the second layer.
  5. Glue it using the Green Glue Compound which you had used to glue the first layer and also the edges of the first layer.

Step 7: Put the Box Together

After installing the second layer to the box, now its time to put the box together. So collect all the pieces and put together the enclosure for the quiet box. 

Assemble the wall and the ceilings that we made out of the fiberboard and attach them to one another using nails and screws. You can also make a small door to access the generator easily. Get creative in this part as per your needs. Also, take care of the ventilation holes that we made earlier which will be taken care of in the next step.

After putting up the box together follow the next step.

Step 8: Installing the Ventilation Duct

After you have put the quiet generator box together with its now time to install the ventilation duct. As I have mentioned earlier ventilation is an utmost priority for the proper functioning of a generator. So you really need to focus on this part. 

For a generator to run properly and smoothly, it is very important to create a nice airflow and supply. If the airflow is not proper then the generator can start overheating and can be caught catastrophe and the risk is very high. It could blast or you might even face fire in some instances. Focusing on this ventilation part will help you in the long run. 

Now install the ventilation duct on the generator soundproofed box or the generator quiet box or enclosure. Make sure to tighten the ventilation duct so that it doesn’t get removed when left unattended. You need to install the ventilation duct on the holes that we created. You can use this method to build a sound proof dog crates too. 

If this text tutorial is tough then you can follow this Youtube video tutorial below, who also explains almost an exact tutorial but with their own additions. 

If you are wondering how to make a generator quiet? then you are in a perfect place. 


Finally, this great tutorial article is done. Didn’t I tell you that this would be an easy and cost-effective DIY soundproofing quiet box to build? If you liked this information and if felt helpful then please do share it with your friends and family who are looking to build a soundproof quiet box for their generator. If you have problems or doubts then you can use the comment box below to leave your feedback. Thank You and visit again.

About Jennifer Porterfield

I am Jennifer Porterfield from New York City, New York. I am the sole writer of this blog. I am a vocalist so i had to built a small studio in my room that’s where my interest on Soundproof started. I learned alot and implemented them. A lot of my friend asked me to teach them that’s where this blog started.

2 thoughts on “How to Build a Soundproof Generator Box (8 Steps DIY Guide)”

  1. No air flow
    Will overheat and ruin the generator and may cause a fire. Also no way to run a cord into it.

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