How to Soundproof French Doors

Are you irritated by the amount of noise coming through your glass doors? Wondering how to soundproof french doors?

It’s hard to deny it – French doors are amazing. They’re styling and classy. Even the most basic model looks a million times better than ordinary-style doors and adds warmth and style to your home. 

But unfortunately, there is a downside to french doors too. The mostly glass doors are notorious for letting a ridiculous level of sound in. With some models, particularly those that don’t have double-glazing windows in them, you can hear almost everything that’s happening outside. 

Luckily, it doesn’t have to be. You can soundproof french doors to at least greatly minimize the amount of noise that they let in, if not block it almost entirely. 

In this guide, you’ll discover how to soundproof french doors. The advice I’m going to show you will work for interior and exterior french doors. 

What you need to know before soundproofing french doors

Before I show you how to soundproof your french doors, I must first explain why you hear the sound through them in the first place.

And it’s all because of the way french doors are made. 

(This also means that you improve their soundproofing qualities by targeting some of those issues.)

How noise travels through french doors

Most of the sound you hear through french doors is called airborne sound.

Airborne sound waves are created when sound travels through the air. Take speaking, for example. The sound of your voice makes the air vibrate. Then, that sound travels through the air until it reaches the other person you’re speaking to.

Music, TV, radio, dog barking, and the sounds of a car passing by your house are other airborne sounds.

Because airborne sounds travel through the air, they also enter houses in the same way. That’s one reason why you hear sounds from the outside louder with doors open. Closing them immediately reduces the intensity of the noise because, with closed doors, there are fewer places through which the sound can enter.

This brings us to the next thing –

How sound enters through closed french doors

Unfortunately, it does so because of a how french doors are made…

First of all, most such doors are larger than ordinary doors. They feature light construction, with the majority of the doors being taken by glass. 

(BTW, this relates to both traditional french doors and sliding doors. There is no difference between them in that regard.)

The additional window panels on each side of these doors shown below might be an extreme example, yet they illustrate the problem well. Most of the wall in this room is glass.

An example of large glass french doors.

Here’s why it’s a problem.

First of all, the doors are larger, meaning more entry points for the sound to get in. With ordinary doors, most of the area around them is a wall. And although walls can let noise in, it’s never as much as what’s coming through the doors. 

You have more gaps and cracks in larger doors through which both air and airborne sound can get in.

(This is important to remember. As you’ll shortly see, you’ll be focusing on those gaps when soundproofing those doors.)

The other problem is that French doors are made mostly of glass. Unfortunately, this makes them poorly soundproofed by default.

Glass lets more sound in than most other building materials. Even a double-glazed window isn’t completely soundproof because the glass will let sound in. That’s because, by its nature, glass has low acoustic properties when it comes to different frequencies. 

This also means that you’ll need to use external materials and several soundproofing techniques to soundproof french doors. 

Here’s how to do it.

How to Soundproof French Doors: 6 Methods for Interior and Exterior Doors

#1. Seal all gaps and cracks

As I said above, gaps are the first thing you target when trying to reduce the noise coming through french doors.

And let’s face it – Regardless of whether your french doors are brand new or they’ve been in the house for years, they will have small cracks and gaps. Even a tiny gap of a few millimeters will allow an incredible amount of noise into the house. 

To put this in perspective, according to research, covering just 1% of gaps in the surface can result in up to a 10% drop in noise coming in!

Imagine the results after filling in the gap between the door frame and the floor. 

How do you soundproof those gaps?

Use an acoustic sealant, ideally the Green Glue.

Green Glue is one of the best acoustic sealants on the market. It works just like any other caulk. You apply it with a caulking gun directly on the crack. Your goal is to fill it, just like you would with any other gap. However, given its soundproofing qualities, Green Glue does more than filling the crack. It also prevents various sound frequencies from entering.

Image of green glue, the best acoustic sealant for soundproofing cracks in french doors.

#2. Add soundproof weather stripping to the frame

Once you’ve filled in all cracks between the frame and the wall, the next step is to do the same for the frame.

In this case, however, you don’t fill in cracks by applying a sealant but by adding weatherstripping. But let’s take it from the top.

Your doors might also have gaps between the actual door and the door frame. These might result from poor manufacturing or because the hinges have slightly tilted with long-term use. As a result, the door doesn’t create a full seal with the frame when you close it, leaving microscopic space through which both air and noise can get in. 

Luckily, the solution to this is quite simple – Attach self-adhesive weather stripping to the doorstop, the sides, and the top of the frame. 

EXAMPLE: Soundproof Weather Stripping Door Kit

#3. Add a door sweep at the bottom of the door

This is another simple method to increase the soundproofing of your door frame. The chances are that the biggest gap is at the bottom of the frame. One way to solve it is by installing weather stripping. 

However, you can also experiment with adding a door sweep. 

A door sweep is an element you add to the bottom of the door that continuously closes the gap between the door and the floor, even when the doors are in motion. Door sweeps are perfect for retaining heat, not letting cold air in but also, blocking the sound from coming in. 

#4. Hang soundproof curtains to block the noise

Let me be clear about this – Despite their name, soundproofing curtains aren’t fully soundproof. This doesn’t mean that they do not help with noise reduction. Quite the contrary. Soundproofing curtains can reduce the intensity of many noises coming into your house from the outside. When you hang them, noises like traffic, barking, and other loud sounds that might be bothering you will be much quieter. 

This is due to certain characteristics of soundproofing curtains:

  • Thickness – Such curtains are much thicker than the usual ones. Because of that, they absorb or block many frequencies from getting in. 
  • Length – Soundproofing curtains are also very long, typically reaching the floor. This way, they leave no additional space for the sound to travel.
  • Density – These curtains are also incredibly dense, making them absorb more sound. 
  • Rough surface – Finally, soundproofing curtains have a rough and porous surface. This prevents sound from bouncing off them and increasing in volume. Rough surfaces absorb part of the sound energy and reflect only what they cannot absorb. This means that the sound that reaches your ears is usually much quieter than without those curtains.

#5. Hang moving blankets

Hanging moving blankets over french doors works in pretty much the same way as using curtains.

Thanks to its inherent sound-absorbing quality, the blanket will naturally absorb some of the sound waves trying to enter your room through french doors.

Just like with curtains, thickness plays the most crucial role here. The most ideal moving blanket to soundproof french doors should be as thick as possible. Ideally, it should also feature grommets by which you could hang them on the curtain rod. And ideally, it should be large enough to cover as much of your french doors as possible. Otherwise, you run into a risk of a significant amount of the noise rolling off it by its edges and still entering the house.

Here’s an example of a large and thick moving blanket that you could use to soundproof french doors.

#6. Soundproof air vents above the door

Many french doors come with built-in air vents at the top. There might also be separate air vents in the walls around the door. 

Those vents help improve air circulation in the room but will also let the sound from the outside in. What’s more, air vents might reduce the effectiveness of any other methods you use to soundproof the french door. 

They will continue letting sound in, after all. So, regardless of how well you’ll fill in gaps and cracks, the noise will bother you because of the air vent. 

One way to soundproof the air vent is to remove it and drywall the gap. But I admit that it’s not always ideal to do it and might affect the air circulation. 

The other option is to create a maze inside the air vent.

The whole concept looks like this:

Diagram showing how to block sound coming through an air vent in french doors.

Notice how, with the maze in place, air (and sound) can no longer pass through the vent. The maze makes it more difficult and requires the sound to bounce from one surface to the other. Each such bounce reduces its intensity and volume. 

The simplest method to create the maze is to install wood or drywall panels inside the air vent, to create a structure like in the image above.

Here’s a great video showing how to create a simple DIY air vent.

#7. Lubricate hinges and handles

This may not be a method helping to block the outside noise, but it’s also something we often forget. Hinges and handles can create quite a noise, only adding to the frustration of poor soundproofing of glass french doors. 

Without oiling, hinges and handles will not move quietly and will keep squeaking every time you open the door. 

The solution to this problem is quite simple – Oil the hinges. You can use any oil – vegetable oil, machine oil; you name it. 

Or you can get a proper hinge lubricant like Liquidfix. It comes with a dropper and a needle pack so that you have everything you need to do a good and clean job out of the box.

#8. Replace your current french door with a double-glazed french door

This is, by far, one of the most effective ways to eliminate your noise problem. Unfortunately, it is also the most costly one. Hence I’ve left it till the end.

When you’ve replaced the current door with double-glazed one, you immediately increase the thickness of the glass. Thicker doors will automatically place a much sturdier barrier for the sound to enter the room.

One way to think about it is that double-glazed french doors will place more resistance on the sound’s path than your current ones, along with any curtains or moving blankets that you might cover them up with.

Granted, you’ll most likely, still have to seal any gaps and cracks around them, as these factors are independent of the door’s quality. However, you probably won’t need to use weather stripping as the new doors will naturally be well insulated.

And that’s it…

Use these six ways to soundproof your glass french doors and block the outside noise. 

Good luck!