How to Make a DIY Soundproof Window Plug

Windows are a code requirement in most areas.

They allow for proper ventilation and natural lighting to fill a room.

However, windows are one of the main ports where sounds come into our homes. 

For this reason, they should be one of the first things you should insulate if you want to create a quiet space in your home. 

Using soundproof window plugs will allow you to either temporarily or permanently seal the windows which can muffle or even block outdoor sounds. 

If you’re interested in learning about window plugs and how to make one or more for your home then keep reading. 

What is a window plug?

Soundproof window plugs can either be a permanent or removable insert that completely covers your windows. 

They help to prevent air, noise and light from entering or exiting a room.

These inserts also act as thermal insulators since they seal gaps that allow for heat transfer to occur. 

Window plugs usually consist of two main components and the first is a wooden board while the other is either insulation butts or acoustic foam. 

Due to the use of these simple materials, constructing a window plug isn’t difficult. 

They are even easier to install and can be removed when needed. 

When constructing window inserts you need to make sure that they fit precisely to the measurements of your windows. 

They should fit snugly inside the wall cavity and the wall itself is going to keep the insert in. 

On the other hand, you can use various types of fastenings to make the insert stay put. 

However, this project depends on whether you have windows that are set into a wall rather than the ones that are flush with it. 

You should start by weather stripping and sealing your windows with weather stripping tape and acoustic caulk before adding a window insert. 

Read more on how to soundproof a window by clicking on the link.

What are DIY soundproof window inserts made of?

Soundproof window plugs are usually constructed from highly dense materials.  

These materials have mass and it is the mass that helps to block out noise. 

Viscoelastic materials are quite popular like mass-loaded vinyl, its many alternatives as well as Green Glue soundproofing compound. 

Keep in mind that materials like MLV do not have sound-absorbing properties but are used for sound dampening instead.

Dampening sounds is the reduction of the resonance through reflection and diffusion. 

Simply put, it means that the sound is dissipated before it has the potential to build up. 

Viscoelasticity describes two concepts: 

• Viscosity- resistance to flow 
• Elastic- can be deformed but returns to its original shape. 

Materials like MLV and Green Glue can do both because they flow when a force is applied and returns to their original shape when the force is removed. 

These materials can be attached to structural supports such as medium-density fiberboard(MDF), plywood or oriented strand board(OSB). 

If you can, try to use MDF since it is a heavier material that can block and reflect sound waves while plywood and OSB cannot. 

Common materials used to make window plugs

This is not an exhaustive list but here are a few common materials used to construct window plugs.

• Thin layers of MDF, Plywood or OSB.
• Soundproof acoustic foam panels 
• Neoprene formats 
• Mass loaded vinyl 
• Stone wool fiberglass panels 
• Green Glue 
• Handles for removable window plugs 

If you are going to build a permanent window plug, consider adding a layer of reflective film for the side of the plug that will be pressed up against the window. 

This allows sunlight to bounce off the plug and will minimize the amount of heat buildup in the space between the plug and the windowpane. 

How to make a soundproof window plug?

Now that you know what window plugs are and the common materials used in construction, it’s time you learn how to make a soundproof window plug. 

1. Measure the window 

You should start by measuring the window that you’re making the insert for. 

Use a basic retractable tape to measure the height and width of the window cavity. 

Instead of measuring the window frame itself, jot down the dimensions of the hole in the wall that holds the window. 

You should double-check your results near the top and bottom of the window when measuring the width of the cavity. 

Similarly, check the numbers on both sides when you’re measuring the height as well. 

Do this because you don’t want to find out that the hole the window is in is irregular after you make the insert. 

If the window is level but the wall around it isn’t you need to fix the edge before making your insert. 

On the other hand, you can opt to make the insert as crooked as the window hole itself since the wall is what is going to be keeping the insert in place. 

You do not want to be leaving gaps around the window plug as noise and light will enter the room which defeats the entire purpose of using a window plug. 

Lastly, measure the depth of the window because the finished plug shouldn’t be too thick to completely fill that space. 

When you press the wooden board flush against the wall there should be a pocket of air between it and the windowpane. 

This space will work as a trap to capture low-frequency sounds and prevent them from coming in.

Gather your supplies 

The next step is gathering your supplies.  

Here’s a list of things to get: 

• ½ “ thick MDF board 
• Green Glue 
• Mass loaded vinyl/ neoprene mat
• Insulation batts or acoustic foam panels 
• Handles 
• A utility knife, staple gun, drill and screws 

As mentioned before, when choosing the wood for your insert you should choose the MDF.  

It may be easier for OSB to stay on the window without fasteners but it won’t be as insulating as MDF. 

However, if you must use OSB combine it with MLV before attaching the insulation or foam. 

You can also purchase some materials you need to make the finished insert look presentable when installed. 

You can paint it to match the color on your wall or use it as an artistic canvas before you attach the other materials. 

All you need to do is to remember to prime the wood before painting it. 

Alternatively, you cover the board using fabric, a thin sponge or a foam mat. 

Once the mat is glued to the board, you can stretch the fabric over it and staple it to the other side of the board. 

This would increase the sound-absorbing properties of the side of the insert that ends up facing the room 

Precut the boards and acoustic materials 

The most difficult part of making window plugs is cutting the materials. 

However, this can be made easy if you get your board from a hardware store that can cut the material for you. 

This will significantly reduce the amount of time you spend building your window insert. 

If not, you will have to figure out a way to cut your boards according to the measurements you took earlier. 

Once the boards are cut, trimming the other materials should be a walk in the park. 

You can use a simple utility knife to cut through acoustic foam, rubber and mass-loaded vinyl. 

Do keep in mind that you may have to score the surface of the material several times before the knife cuts through. 

 If you’re having a hard time then you can probably use regular scissors to get the job done.

Assemble the plug

Once you have your materials cut and ready to assemble, things are going to be a breeze because all you need to do now is to glue and screw it all together. 

So the correct order to stack everything is to begin by putting down the wooden board with the presentable side facing the floor. 

Slip on a pair of work gloves and pour some glue onto the board.

Spread it across the whole area stopping an inch from the edge. 

If you choose to use Green Glue, spread it across the board in a thin layer to provide another soundproof barrier. 

When the glue gets tacky, lay a sheet of rubber or mass-loaded vinyl on top by pressing down in the middle on running your hands towards the sides to remove any air bubbles. 

Ideally, you want a smooth surface. 

You can staple the edges of the MLV to further secure it before moving on to adding the foam. 

It may be better to construct foam window plugs rather than using batt insulation.

This is because foam is thinner and easier to glue onto MLV but it may not be better at trapping sounds so if you have a particularly deep window, use batt insulation. 

If you are going to use foam then put down another thin layer of Green Glue and lay the acoustic foam.

Again, you want to start from the middle and push out to remove creases and air bubbles. 

If you are going to be using batt insulation, you should use staples, nails and screws to secure it.

Once you’re done putting everything together, leave the insert for the recommended time the manufacturer of the glue says it takes to set.

Attach the handles

After the recommended time has elapsed and the glue is completely dry, flip over your soundproof window plug and attach the handles. 

The type of handles you use will depend on your personal preferences and can include classic kitchen cabinet handles, round planetary cabinet knobs or nylon strap handles. 

It is best to keep the handles at the same height and at least two inches away from either side of the board. 

If your insert is extra wide, make sure you can grab both handles without completely stretching your arm. 

Work on the presentation

Like we said before you can either paint or upholster the wooden part of your window plug to make it a little more presentable. 

However, these are things you’d have to do before you assemble the insert. 

Let us now discuss how you could make it less noticeable with some other methods. 

if you’re not going to be taking off the insert anytime soon you could cover the window with tapestry or a large poster. 

You can attach these using nails, tacks or hook and loop tape. 

Placing a large piece of furniture that covers up the window area also works.

If these don’t appeal to you then you can simply hang some soundproof curtains which will hide them away.

For the best soundproof curtains, check out this soundproofing curtains review.

Advantages of using window plugs

Window plugs offer a wide range of benefits including the ability to: 

Effectively reduce the transmission of sound waves.  

This means that it will reduce noise disturbances in your home. 

No longer will the neighbors playing loud music during the day, the sound of traffic, children, animals and other outdoor sounds disturb you while taking a nap, getting some work done or simply enjoying some quiet time. 

They also make sure that the neighbors aren’t disturbed by any loud noise you make in your home. 

Significantly lower thermal energy loss 

Window plugs seal gaps around the windows so there will be no more wastage of central heating/ air conditioning as well as reduced hot/ cold air coming in from outside. 

This can lead to significantly reduced utility bills and a far more comfortable living space. 

Improve acoustics in a room 

Openings in walls can ruin the symmetry and balance of sounds.  

Add glass and you get unwanted rattles and echoes. 

Music enthusiasts will benefit greatly from using an acoustic window plug because the room will then have a smooth frequency response.

Provide blackout properties 

If you’re someone that likes to take naps during the day or have kids, then window inserts can help.  

They offer blackout properties that can help you to sleep better as well as prevent sun damage to furniture, flooring and décor that cause them to fade or discolor.

Be cost-effective 

When compared to specialized soundproof windows or other proofing methods, window plugs are a cheap and simple solution that prevents outside noises from coming into your home. 

It is way cheaper to make a soundproof window plug than installing a new window so homeowners and renters can use this simple solution. 

Disadvantages of using window plugs

There are downsides to using window plugs. 

They are bulky 

Window plugs can be bulky so this makes it difficult to move them around and store them when not in use.  

While you may not be able to prevent the size, you can add handles to make it easier to remove an insert. 

They prevent you from using the window 

If you want some fresh air, natural light or to look through the glass on your window then window plugs will prevent you from doing so.  

It is important to install removable window plugs if you think you’ll want to use the window for any of these things.

They may not block all low-frequency sounds 

This depends on the thickness and density of the materials used to construct the window plug.  

Choose materials that are designed to be soundproof such as mass loaded vinyl and acoustic foam that will block the majority of sounds 

Not all windows can support window plugs 

Windows that are built flush to the wall will not support window plugs. 

Other types of windows may support window plugs but if it’s not made to the right size and angles, you will have to secure the plug with straps or by adding a stool extension.