11 Ways to Soundproof a Hollow Core Door

Many modern homes feature hollow-core doors because they are less expensive, lighter, and easier to install than the less common, solid-core doors.

The problem with them is they’re not effective at blocking or absorbing sound. Meaning, if you live in a busy environment, it will be challenging to keep sound in and out of your space.

Today, we’re going to walk you through 11 effective methods you can use to soundproof a hollow-core door and finally get some peace and quiet. Before we get into it, though, there are a few things to consider during any soundproofing project.

Consider the Area Around the Door

It’s not just your hollow door that lets sound escape; you should also consider the walls surrounding your door.

Whenever possible, you should aim to soundproof the walls opposite the door of the room you’re trying to soundproof. Doing this will help block noise from traveling through your walls and echoing throughout your space.

Control the Air Movement

All doors inevitably have gaps and cracks around them unless they’ve already gone through acoustic treatment. Any of these spaces that allow airflow will also be a culprit for letting sound in and out.

Even the smallest gap will allow sound in; keep this in mind when you’re soundproofing problem areas like around a door, you’ll have more success and a quieter home.

How to Soundproof a Hollow Door

To effectively soundproof a hollow door or any space for that matter, you need to use materials that vary in density to target the different frequencies.

Because these doors are hollow, they aren’t dense and don’t have much mass; therefore, they aren’t efficient at keeping sound in or out. Luckily, there are quite a few ways you can improve on the soundproofing qualities of your door.

Let’s jump into it.

1. Seal Internal Gaps With Insulation Spray

You want to fill the space left between the drywall and door framing; this may or may not be possible depending on how your door was constructed.

Begin by carefully removing the door casing to easily access the gaps. You may need to cut caulking that’s been applied between the casing and the wall; otherwise, you risk damaging the drywall or paint job.

After removing the casing, use your insulation spray to fill the space on each side and over top of the door. It works best to fill from the bottom up if you have a large gap wider than 1/2 inch. Don’t forget to do the same on the opposite side of the door for the best results.

2. Seal All External Gaps With Acoustical Caulk

Now that you’ve taken care of the internal gaps and your casing is back on, it’s time to fill the rest of the gaps that sound can make its way through. Using special acoustic caulk will better prevent noise from traveling in and out through your frame.

Check your door jam and casing for cracks that need to be recaulked or sealed, including where you previously cut to take off the casing. Be prepared to remove some of the old caulking before reapplying it to seal the entire frame.

3. Install a Door Sweep

Generally, the bottom of your door has a reasonably large gap to allow it to open and close freely without scraping the floor. A lot of sound travels in this airway; to effectively solve this problem, you should install a door sweep.

Installing the sweep along the bottom of your door seals the gap without damaging your floor. Door sweeps are easy to install and usually adjustable or easy to cut to the correct size for your door.

4. Install Weather Stripping

Now to tackle the remaining small gaps between your door and the frame. Like the bottom of your door, you must seal these cracks regardless of their size if you want effective soundproofing.

The best option for this is to install weather stripping around the sides and top of your door. Many weather stripping options are inexpensive and made from self-adhesive foam, which is easy to install and creates a tight seal around your door.

5. Install a Sound Absorption Sheet

While this option may not be suitable for doors you frequently use, it effectively dampens unwanted noise. The sound absorption sheet works by hanging over your door and absorbing the frequencies that come through your hollow-core door.

To install it, start by drilling anchors into the wall above the door the same width apart as the grommets on the sheet. Next, hang the absorption sheet on the fasteners and screw them into the anchors on the wall.

6. Install a Layer of Mass Loaded Vinyl

Like we mentioned earlier, you want varying material densities to ensure you’re targeting the entire frequency range. This step is where Mass Loaded Vinyl (MLV) becomes very effective. It’s incredibly dense and will absorb the lower bass frequencies that many other products aren’t effective at blocking.

There are a couple of ways you can attach MLV to your door:

1. Attach it to the front or back of your door by applying velcro on both the door and MLV. Altnertiavely, attaching industrial magnets to the MLV will also work if you have a metal door.
2. If you don’t use the door, install a metal frame around it. Next, attach industrial magnets to the MLV and hang it on the metal frame, covering the entire door and any gaps.

7. Install Blackout Curtains

While they’re designed to block out light, blackout curtains are also effective at muffling sound. If you also installed MLV on or around your door, add these curtains to make your space more visually appealing while adding another layer of soundproofing.

They’re easy to install and generally come with all the hardware you need. Attach the rod holders above your door, slide the rod through the grommets on the curtains and hang!

8. Install a Soundproof Panel

Soundproof door panels are a more costly investment. Still, if you’re trying to soundproof a room that requires very little distraction (theatre room, recording studio, home office), it’s worth it. These door panels are effective because of the sound barrier and sound absorption components in their design.

Installing the panel is an easy process. You order it custom-fitted to your door and attach it using high-quality velcro.

9. Install Acoustic Foam Outside the Door / Wall Opposite

Acoustic foam will help absorb echoes and the middle to high-end frequencies. If possible, hang the foam up on the outside of your door and also the outside wall. As we mentioned initially, your door isn’t the only way sound travels throughout your home. By absorbing the frequencies along the wall as well, you will have a much quieter space.

Installing acoustic foam is easy, and there are two methods that we found work the best:

1. Use double-sided adhesive squares.
2. Attach the foam to a piece of cardboard using spray adhesive, then attach the cardboard to your door/panel with adhesive squares or Command strips.

10. DIY Floor to Ceiling Plug (For Sleeping)

For a hands-on approach that’s more of a permanent feature, you can essentially create a “plug” for your door. Here’s what you’ll need:

• Wood planks (length will depend on your door)
• Foamboard
• Foam tape
• Fabric
• Pink insulation
• Staple gun

You can create a floor-to-ceiling plug or one that sits within the frame and covers just your door for this method. Your choice should depend on how frequently you need to use the door and if you also want to block the frame.

Let’s get started:

1. Create a wood frame that sits up tight against your door. Or a floor-to-ceiling frame that is as wide as the door and frame.
2. Cut and add the foam board inside the frame.
3. Add the pink insulation to the frame for better soundproofing and seal it with foam tape.
4. Cover the frame with your chosen fabric and staple the edges.

11. Install a Solid Core Door

If you’ve followed through on all of these steps and are still unhappy with the results, then installing a solid core door is your next best option.

They’re heavy and very dense, making them difficult to handle, making them much more effective at blocking sound.

Final Thoughts

Just because you have a hollow-core door doesn’t mean you have to live in a distracting and noisy environment. Use these 11 methods, and you’ll notice a difference in the level of noise in your home.