Most houses nowadays have hollow interior doors, which are fine for saving money, but awful when it comes to soundproofing. Doors are usually the weakest part of a room, and I’m always on the lookout for ways to soundproof a hollow door.
So, can you soundproof a hollow door? It’s entirely possible to reduce the amount of noise coming through a hollow door through a combination of different methods, including adding mass and dampening. However, it’s impossible to completely soundproof a door because of its very nature as a door.
Soundproofing a hollow door can take a lot of work, but it’s definitely possible to improve its noise-blocking ability. Also, there are other options you can try instead if you’ve got the budget and DIY skills. In this article I look at the best ways to soundproof a hollow door, along with alternative options.
If you’ve not read my article on best ways to soundproof a door, I suggest you check it out.
How to soundproof a hollow door
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Manufacturers of interior doors generally make them hollow to save time, money, and resources. While the door still does its main job, this means they’re absolutely awful at blocking out sound. I’m always trying to find ways to improve a door’s noise-blocking ability, and hollow doors are my worst nightmare.
There are many reasons why you might want to soundproof a hollow door. For example, if you live in an apartment with noisy housemates, you’ll want to do something to block them out. However, building regulations usually prevent you from completely changing the door, so you’ve got to look for other options.
As with any soundproofing job, the best way to soundproof a door (other than blocking it up) is to add mass, as much as possible. However, you’re limited by the fact that the door can’t be too thick, otherwise it won’t open properly. This means finding the product with the right thickness to noise-cancelling ratio.
The best product I’d recommend is sound deadening foam, such as car interior foam like Dynamat or Hushmat (Amazon links). This is really easy to install, and is usually less than an inch thick, meaning your door will still open and close properly.
If you choose one of these products, I’d recommend sticking it to a sheet of wood or drywall that you can then screw to your door. This is because the sound deadening mats have self-adhesive backing, which is easy to use, but not so easy to peel off. What’s more, it’ll definitely leave some adhesive behind on the door.
Another option is specific sound deadening fiberboard, but this is much more expensive. Using vehicle sound deadening mats fitted on a piece of wood is probably the best way to soundproof a hollow door because it’ll add thin mass that’s pretty effective at absorbing sound.
Alternatively, try mass loaded vinyl (see it on Amazon). This is what’s known as limp mass, meaning sound waves just dissipate against its surface. It’s not too expensive and isn’t very thick either. However, it might be a bit heavy to fit on a door, which will depend on how sturdy your hinges are!
While there are plenty of ways to add mass, some more effective than others, it’s going to be impossible to completely soundproof a hollow door. This is because you’re affected by the gap around the door, the frame, and the materials they’re made from. However, there are other things you can try to help with these problems.
Some tips for soundproofing a hollow door
Soundproofing a hollow door effectively goes beyond just adding mass to the door. For example, if you want to soundproof an internal door, then you should consider doing everything possible to address its other weak areas. Here are my top tips on improving the sound-blocking ability of a hollow door.
1. Focus on the gaps
Doors, by their very nature, have a small gap around them when they’re sitting in the frame. However, this necessary gap is also ideal for letting in noise, and finding ways to block it as much as possible will make a big difference to noise pollution.
Try a soundproof door strip, such as a door gasket designed for fire safety. Many insulation and fire control products work great for soundproofing because they follow many of the same principles. These door gaskets will help to create an airtight seal around the door when it’s shut.
Similarly, you could add weather stripping, which simply goes around the edge of the door to make the gap smaller. Weather stripping is less invasive than a door gasket, which is ideal for soundproofing an apartment door because it won’t leave any trace.
2. The frame needs attention
Aside from replacing the door frame with solid metal, there are only a few things you can really do to make it more soundproof. The first thing I’d try is to add as much mass as possible, for example cutting up some sound deadening mats and sticking them to the door frame.
However, this will be limited because it could stop the door opening. Another idea is to seal any cracks or gaps in the door frame with acoustic caulk, such as Green Glue (Amazon link). Unlike regular sealant, acoustic caulk is silicone-based, meaning it won’t crack if the house moves.
3. Don’t forget the other side
The best thing you can do to soundproof a hollow door is to add mass on both sides. As with all soundproofing projects, mass is the key for absorbing and blocking sound waves, although it can be helpful to add other acoustic management products to the door’s exterior.
If you build another soundproof door cover like the one suggested above and fix it on the outside of the door, you’ll increase your soundproofing massively. However, the main downside is that it might not be the most attractive thing, but you could always find ways of disguising it.
Another useful addition is acoustic foam. While this doesn’t directly help with soundproofing, it treats echo and reverberation by creating a textured and open-celled surface that sound waves can’t bounce off. Basically, this will mean it’s harder for the sound waves to reach the door in the first place.
Alternative ways to soundproof a hollow door
Although sound deadening mats or mass loaded vinyl aren’t the hardest materials to get hold of, there might be reasons why you can’t use them. Instead, there are some more readily available solutions you can try.
Just be aware that these won’t really be as effective, but will provide some noise reduction. Here are my best options for how to soundproof a door with household items.
1. Use soundproof curtains
Installing a curtain rail above your door is a pretty easy job, and it’ll allow you to hang soundproof curtains in front of the door. Pulling these shut when the door is closed will make a noticeable difference to the noise coming through.
Alternatively, you could use heavy drapes, such as velvet. Curtains do a good job of soundproofing because they’re often made of heavy material that dampens the sound waves. Soundproof curtains across a door will also help to keep heat in, which can be both a positive and a negative.
Check out my guide on soundproofing curtains.
2. Try a soundproof blanket
Using a soundproof blanket for door insulation isn’t necessarily the best option, but it’s very easy to install. All you need to do is fit hooks on the door and you can hang the soundproof blanket from them.
Choosing this option will be even more effective for soundproofing a hollow door if you hang blankets on both sides. You could try using normal blankets that are thick, but I’d recommend at least stretching to soundproof blankets if you’re going to go for this option.
3. Dampen the noises
An alternative to soundproofing a hollow door is to manage the noises closer to their sources, which will hopefully reduce the amount of noise pollution that even makes it to the door. However, I’d consider at least trying this option alongside some sort of soundproof cover for the door.
If you’re trying to soundproof a door to a hallway, consider laying rugs on the floor, as this will help reduce echo and vibration. Similarly, hang paintings or frames on the walls to reduce echo further.
Inside the room, consider placing heavy furniture, such as bookcases, near the door. While this won’t necessarily improve soundproofing, it’ll help with things like echo, and the dense books will also absorb sound waves.
Some final thoughts
The best way that I found to soundproof a hollow door is to use some thin yet dense mass, such as sound deadening car mats or mass loaded vinyl. However, these options can be more expensive, and need a bit of DIY knowledge to complete.
Luckily, there are some options for soundproofing a hollow door using household items. If you go with one of these, just remember it won’t be as effective as a dedicated soundproof product. Either way, it’s going to be impossible to completely soundproof a hollow door, but there are definitely things you can do to make a difference.
Thanks for reading! Also check out my recommended products for soundproofing.