How to Build a Soundproof Box for your Generator

soundproof box for generator

Generators are an extremely useful resource during a power outage. The only problem is that they tend to be very loud. For generators or air compressors that produce a lot of noise, you might need a generator soundproof box. Fortunately, you can build one of these yourself with a few simple steps.

Let’s discuss how to build a generator soundproof box.

List of Supplies

  • Measuring tape
  • Medium density fiberboard
  • Go Board backer board or any lightweight foam backer board
  • Pink fiberglass insulation
  • Mass loaded vinyl
  • Osculating multitool or jigsaw
  • High heat paint
  • Handle
  • Copper extended exhaust pipe

Out of this list, mass-loaded vinyl could be the most expensive item. However, you won’t need much of it and it is incredibly effective in soundproofing.

Create Your Soundproof Box

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A generator soundproof box is simply a wooden frame that is packed with insulation and placed over a generator. It has many of the same materials that you would use to soundproof any surface. By using medium density fiberboard, backer board, fiberglass insulation, and mass-loaded vinyl, you can significantly reduce the noise that your generator produces.

Before building your generator soundproof box, there are a few things to keep in mind. When soundproofing a surface, it’s important to seal all air leaks for the best results. However, generators need air ventilation to work properly.

You don’t want your generator to overheat. If you completely seal your soundproof box, you’ll likely cause this problem. When building a generator soundproof box, make sure to add some air vents.

Because generators need ventilation, you can’t fully soundproof a generator, but you can deaden some noise. After you build a soundproof box, you could cut space to insert a fan. This will make sure that your generator never overheats.

To start building your DIY soundproof box, here are some steps to follow.

Step one: Measure your generator. Make sure to add a few extra inches on each side of the box to leave room for soundproof insulation.

Step two: Cut two sets of wood legs that are a couple of inches taller than the generator. Use 2 x 2 medium density fiberboard for this.

Step three: Cut smaller blocks, two for each of the four legs. Place these in the center of each leg, both facing in.

Step four: Screw the two small blocks onto the inside of each leg. These will be used to create space for the internal panels and insulation.

Step five: Cut two more pieces of wood to match the length of the generator. Screw each of these pieces to the top of the legs, making two wooden frames. The backer board will be used as side panels, which will hold the box together.

Step six: Cut pieces of Go Bard backer board to the length and width needed. Make panels for the inside and outside of the box.

Step seven: Lay the panels all around the outside of the box. Screw them into the wood frame. Leave the bottom of the box open.

Step eight: Place pieces of the backer board along the inside of the box as well. Screw these into the frame.

Step nine: For added insulation, add a layer of mass-loaded vinyl to the interior of the box.

Step ten: Cut sheets of pink fiberglass insulation. Place these in the space left between the two layers of panels.

Step eleven: Cut four pieces of fiberboard to fully close the internal gaps of your box. Screw them in to seal off the insulation space.

Step twelve: Cut out a channel for the exhaust pipe using an osculating multitool or jigsaw.

Step thirteen: Spray all areas of the box with high heat paint.

Step fourteen: Install a handle to the top of your box to easily lift the box onto the generator. This also makes it easy to transport.

Step fifteen: Install a copper extended exhaust pipe to reach through the box.

Step sixteen: Cut a channel in the box for this exhaust pipe.

Step seventeen: Place the soundproof box over the generator, making sure to align the exhaust pipe with the channel.

After you’ve finished building your soundproof box, you can use it to muffle your generator noise whenever you’d like. You should be able to notice a significant decrease in sound output.

Since generators need air ventilation, you may need to drill extra holes in this soundproof box. Another option is to install a fan. This process is fairly simple and only requires a few extra steps.

Step one: Find the center of the box and trace the shape of your fan.

Step two: Cut an opening using the traced outline.

Step three: Mount the fan in this open space, between the two panels.

Step four: Apply a construction adhesive to attach the fan.

After you have glued the fan into the side of the soundproof box, place the box on the generator. Check to ensure that the box still fits over the generator.

Final Thoughts

Everyone has a generator to power their homes during emergencies and power outages. Although generators can have many great uses, they produce a lot of noise. Having a loud generator next to your house could be bothersome, so it might be time to build a generator soundproof box.

You can easily build your own soundproof box by building a wooden frame with soundproof insulation. By following the steps listed above, you can create a custom-sized box to fit your generator.

For soundproofing to be effective, you need to seal all air leaks. Unfortunately, generators will need some airflow so that they don’t overheat. You should insulate the box as much as possible, but also add some ventilation holes. You might even need to add space for a fan.

Keep in mind that you’ll likely only be able to reduce 50% of the generator noise. Having a fully soundproofed generator would be ideal, but this would cause the generator to overheat.

With a generator soundproof box, you can effectively reduce most of the sounds a generator makes. After a few simple steps, your home can be much more quiet and comfortable.

  • Gregory A Seely
  • Gregory A Seely

    Greg is a self taught home renovator and writer for RenoViso. His shares his experiences with Southern Living, Traditional Home and other publications.

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