If you’ve ever had to deal with excess noise in your home, you’ll already know that doors are one of the weakest areas for sound transmission.
Well, if you’re wondering how to soundproof a door, here are some actionable solutions:
- Seal gaps in the frame
- Install weather stripping
- Fit a door sweep
- Make a DIY door cover
- Use vehicle sound deadening mats
- Hang soundproof blankets
- Use acoustic curtains
- Use a soundproof door kit
- Fit a new door
I’ll discuss these in more detail below, but first it’s worth going over the types of door you might be trying to soundproof. It’ll help you to understand what makes a door weak soundproof-wise.
Hopefully, by the end of this article you’ll have the perfect solution to your noise problem.
Types of Door
To understand how to soundproof a door, we need to first consider the type of door you’ll be dealing with. This isn’t an exhaustive list but simply a summary of the most common styles.
Interior door
As the name implies, this is a door between 2 interior rooms. Interior doors don’t need the same kind of weather protection as exterior doors and are often more detailed.
You might have any of the following as an interior door:
- Panel door
- Flush door
- Bi-fold doors
- Accordion doors
- Glass doors
Interior doors might be solid, particleboard, or hollow depending on the price and purpose.
The main weakness of an interior door is that it’s mainly just designed to fill a hole in the wall. As a result, they’re nowhere near as sturdy as an exterior door.
Similarly, glass doors will be much harder to soundproof because glass is a weaker material when it comes to sound transmission.
Direct solutions include:
- Weather stripping around the frame
- Adding more mass
- Replacing the door entirely
Hollow door
While hollow doors will almost always be interior doors, they deserve their own discussion. As the name implies, these doors aren’t solid. They have a cardboard honeycomb structure inside MDF sheets pressed onto a frame.
You can check out this video for information on how hollow-core doors are made.
The weaknesses should be obvious: with no core, the door has very little mass. They might be an inexpensive solution, but they’re awful for sound transmission.
In essence, hollow doors amplify sounds, which can make both impact and airborne sounds appear louder.
Annoyingly, the honeycomb structure inside prevents you from filling it with sound absorbing materials. This would solve the amplification/resonance issues.
Direct solutions include:
- Adding mass
- Replacing the door
- Soundproofing the door frame
Metal door
Metal doors aren’t that common in homes, but you might have one in your garage, workshop, or other outdoor space. Alternatively, something like a security door or fire exit will usually be made of metal.
Most metal doors are made from panels fixed to a frame. Security doors might be solid but it’s standard for metal doors to be hollow or filled with insulation materials. Check out the video below to learn about the manufacturing process.
Other than the issue with hollow doors mentioned above, metal is a very good transmitter of sound (which isn’t what we want).
Direct solutions include:
- Dampening materials to reduce vibration
- Adding mass
- Replacing the door
Doors and Soundproofing
If you’re trying to reduce sound transmission into a room, you need to pay attention to the door. We often pay attention to areas like walls, ceilings, and floors but forget about the piece of wood filling the large hole in the wall.
Say, for example, you have a wall adjoining a noisy room that’s roughly 80 square feet. Based on the area of a standard American door (which is 16 square feet), the door takes up nearly 20% of the surface area.
Let’s compare this in terms of a useful soundproofing rating: sound transmission class (STC). As I discuss in my post on soundproofing ceilings, the STC of a half-inch sheet of drywall is 33.
On the other hand, a door should have a STC rating between 20 or 30 depending on whether it’s hollow or solid.
It’s reasonable to assess that the STC of the whole assembly (wall and door) would be somewhere closer to the STC of the weakest element (around 20). Of course, it’s impossible to say accurately without considering all the variables such as gaps or the junction between the door and wall.
An STC rating under 30 is very weak soundproof wise. Knowing how to soundproof a hollow door will help you to increase the STC and address this weakness.
All solutions proposed below for soundproofing a door rely on one of 3 general steps:
- Sealing air gaps
- Adding mass
- Adding absorption
How to Soundproof a Door – Solutions
Now that we have a better idea of doors and the importance of soundproofing, it’s time to look at some actionable solutions.
These are applicable regardless of the type of door you’re soundproofing, although you might not need to use them all on something like a solid or exterior door.
Here are my top solutions for how to soundproof a door.
1. Seal gaps in the frame
Before even starting on the door, it’s worth considering the frame. While there’s not as much you can do to the frame, there is one product worth using: caulk.
Acoustic caulk works in exactly the same way as normal caulk: you use it to fill small cracks and gaps. The benefit of acoustic caulk is that it’s a viscoelastic compound.
In short, this means that, even after it cures, it stays slightly elastic. This allows it to stop sound leaks through small cracks and gaps in the doorframe.
Over time, your house might settle. This can cause doorframes (which are rigid) to shift, causing cracks. This makes them an ideal sight for sound leakage, which I discuss in more detail in my post on soundproof door blankets.
2. Install weather stripping
Weather stripping is a product typically used on windows and exterior doors. It’s designed to fill in small gaps to provide better thermal insulation.
But, luckily, sound and heat follow many of the same transmission principles, making this a good product for soundproofing a door.
Get good quality, high-density weather stripping (such as this) and run it along the inside of the doorframe.
Your aim is to create a tight seal when the door is shut, ideally by compressing the weather stripping. The tighter the seal, the better it’ll be at blocking sound.
3. Fit a door sweep
A door sweep follows the same principle as using weather stripping, except it’s for the bottom of the door.
It’s quite common for there to be a gap underneath the door. This can let a surprising amount of sound through, as I discuss in my post on soundproof blankets for doors.
You have a couple of options for the type of door sweep you fit. The first would be a foam draft excluder (such as this one). The second would be to use a silicon or plastic door sweep (like this one).
The benefit of using foam is that it’d function much like foam soundproofing products. It would absorb a level of noise pollution rather than blocking it.
A plastic door sweep, however, would help to reduce the size of the air gap through which sound can travel.
Regardless of what other solutions you use to soundproof your door, it’s worth doing something to block the potentially large gap at the bottom.
4. Make a DIY door cover
Making a DIY soundproof door cover really isn’t as difficult as it sounds. While it does involve a bit of cutting, most of the work is simply sticking products together.
The purpose is to add mass and sound blocking materials. Importantly, it can be a temporary or permanent solution depending on how you fix it to the door.
For this DIY soundproof door cover, you’ll need:
- MDF or plywood
- Mass loaded vinyl (MLV)
- Glue
- Acoustic sealant
- Acoustic foam
The steps are as follows:
- Measure and cut your MDF to the same size as the door. You’ll want it to sit flush over the door when it’s in place.
- Glue your mass loaded vinyl to the MDF and seal around the edges with acoustic sealant if necessary.
- Fix a layer of acoustic foam over the top of the MLV if you want it to have some acoustic management properties too.
- Screw to the door. The compression under the screws’ heads should leave no gaps in between the layers. If you need to uninstall the door cover, unscrew it and fill the gaps in your door with wood filler or acoustic caulk.
Be wary, as you might need to change the door’s hinges depending on how much weight you add. Roughly, residential hinges can support 200 lbs, and you’ll add around 25lbs if you pick a MLV of 1lb/square foot. Check here to estimate your door’s weight and if you need to replace them with heavy duty hinges.
5. Use vehicle sound deadening mats
An easier solution to the DIY soundproof door cover mentioned above is to use vehicle sound deadening mats.
The main benefit of using sound deadening mats (such as these from Dynamat) is that they have a self-adhesive backing. As you can probably guess, this makes applying them much easier.
The Dynamat Dynapad (linked above) has an STC rating of 28 and will help to both block noise and absorb sound.
Dynapad is a good choice because it contains sound-absorbing foam and a Dynil sound barrier. This, like MLV, has a density of 1lb per square foot.
Sound deadening mats are also good against low frequency wavelengths, such as bass from a speaker system.
But I wouldn’t recommend this option in a rental property. Sound deadening mats aren’t designed to be removed and so could leave some residue on the door, or could lead to it needing replacement.
If you want to try this solution in a rental property, I recommend fixing the sound deadening mat to a thin sheet of rigid board (such as plywood or gypsum board) and then fixing this to the door. While the board won’t contribute to the soundproofing, it’ll be much easier to remove.
Again, it’s important to determine how much your door will weigh with these additions.
6. Hang soundproof blankets
Soundproof blankets are a good option for doors because they’re easy to remove when you need to use the door. I recommend this option if you want to soundproof a bedroom door or other high traffic area.
I have a whole post on which is the best soundproof blanket to use on doors. If you have the money, a professional soundproof sheet such as the Audimute is the best option.
But if you’re on a budget, a heavyweight moving blanket will also do the job. They often have cotton batting sewn in, which provides reasonable sound absorption.
I recommend choosing one with grommets, as this makes it much easier to hang. You’ll just need to install some heavy-duty hooks (such as these) above the door.
If you choose a blanket without grommets, the easiest solution is to sew a rail into the blanket and then hang this from 2 or 3 hooks above the door.
A soundproof blanket (particularly a professional one) is a good solution because it’ll reduce sound transmission and increase sound absorption. One of my other picks on the list, the AlphaSorb blanket, has an STC of 19, which is nearly as good as the door itself!
7. Use acoustic curtains
Fitting a soundproof door curtain is another useful solution for high-traffic areas. Much like the soundproof blanket, it’s easy to move whenever you need to go through the door.
With soundproof curtains, you really get what you pay for. Products at the higher end of the price scale (such as these) are lined with felt, which offers good sound absorption. It won’t block much sound but will do a good job at muffling incoming noise.
If you’d like a wider range of products, check out my article on the best soundproof room divider curtains.
You could either install a curtain rail above the door or fix the curtain directly to the door using Velcro. This option would make it much easier to open and close the door without moving the curtain.
Using soundproof curtains will also help to trap heat and block out light. This makes them helpful on doors made of glass.
8. Use a soundproof door kit
A soundproof door kit (like this one) essentially includes a door sweep and door seal in the same package.
While you can buy the standard products separately, the benefit of this pack is that a soundproofing company makes it. This means the materials are specifically for blocking sound rather than insulating heat.
Importantly, too, both products are self-adhesive, which makes installation quick and easy.
9. Fit a new door
If you’ve got the budget, replacing a hollow door with a solid one will be the best starting point. Solid doors have an STC of 30, while hollow doors are 20.
Of course, this’ll also be the most expensive option. A solid door could cost as much as $500 depending on the style and materials.
Conclusion
Hopefully, this article has given you some practical solutions for how to soundproof a door.
My top suggestion is to add more mass, particularly if the door is hollow. But first it’s worth starting with inexpensive solutions such as sealing any gaps in the frame and around the door. Once you’ve taken care of these small jobs you can then see if it’s worth improving the door’s soundproofing properties.
Do you have any other useful tips for soundproofing a door? I’d love to hear from you in the comments below.
