How to Soundproof Bi-fold Doors: 6 Methods

Bi-fold doors are a great way of opening up a room in summer, however they are not great at keeping sound out.

The best ways to help soundproof your bi-fold doors are to:

  • Seal the Cracks
  • Seal the Gaps Between the Door and Floor
  • Use Soundproof Blankets
  • Use Soundproof Curtains
  • Apply Soundproofing Paint
  • Replace the Glass

Keep reading for instructions on how best to do each of these to keep noise transfer through your bi-fold doors to a minimum.

Things to Do Before You Start Soundproofing Your Door

Before you start here are some important things that you need to do:

Carry out a Thorough Visual Inspection

The first thing you need to do is to assess the amount of sound that the bi-fold door is leaking. A lot of people think that their bi-fold doors are leaking sound because their glass panels are thin.

soundproof bi-fold doors

In many situations, this isn’t the case. Instead, the leakage can be due to cracks or gaps in the door. 

By carrying out a careful visual inspection of the door frames and connecting walls, you might be able to find the real culprits behind the sound.

Check the Thickness of the Glass Panel

Although we said that it’s most likely not the reason, there’s still a chance that the glass panel is a bit too thin to insulate against sound.

If you’re sure that there are no air leaks due to cracks or gaps, make sure that the glass thickness is acceptable. Usually, a single glass panel as thin as ¼ inch is good enough to keep the sound out however double glazing is far more effective.

Check for Air Leaks

In some cases, the source of air leaks might be so tiny that you can’t find them by visual inspection. The easiest way to find those air leaks is to check the door in the dark. 

You’ll need someone to run a flashlight across the door from the other side. The gaps and cracks will let the light through.

You can also use incense sticks in various parts around the door. The smoke coming out can give you an insight into the point where the air leaks.

You could even try more advanced tools, such as a non-contact thermometer (amazon link). It will show the spots where air leaks by giving colder readings.


Also Read: How To Soundproof A Door


Methods to Soundproof Your Bi-fold Doors

Now that you have a better idea why sounds is getting through your doors it’s time to get to work. There are a lot of methods that you can use to soundproof your bi-fold doors. 

Let’s have a look at them:

1. Seal the Cracks

Sealing cracks is a quick and affordable method which doesn't require professional help.

The best way of sealing your cracks will vary depending on which materials you use. Below is a brief overview for each material type:

Apply Insulating Foam

Insulation foam is great for sealing crack in doors. After you spray it, it creates an airtight seal preventing the air from flowing through the crack. 

Another good thing about insulation foam is that you can paint it so it matches the rest of your door.

Foam is extremely easy to work with:

  1. Clean the surface first with some paper towels wetted with a cleaner like acetone.
  2. Spray the insulating foam right onto the crack and wait for it to dry.

The Great Stuff 157906 Insulating Foam Sealant (below) is among the best products in the market to do this job. However, you should know that it works better for larger cracks. 

Great Stuff 157906 Insulating Foam Sealant, 12 oz, Cream
399 Reviews
Great Stuff 157906 Insulating Foam Sealant, 12 oz, Cream
  • The product is 12OZBigGap Foam Sealant
  • Elegant design and Smooth finish
  • The product is manufactured in United States

On the other hand, Red Devil 0913 Foam Sealant (below) works better on smaller cracks less than 1 inch in diameter.

Red Devil 0913 Foam & Fill Small Gaps & Cracks Expanding Polyurethane Foam Sealant, 12-Ounce, Off...
107 Reviews
Red Devil 0913 Foam & Fill Small Gaps & Cracks Expanding Polyurethane Foam Sealant, 12-Ounce, Off...
  • Foam & fill minimal expanding polyurethane sealant, 12 FL. Oz. - 292258
  • This is highly durable
  • This is manufactured in United states

Applying Weatherstripping Tape

Weatherstripping is designed to protect your house from extreme weather. However, they are also effective at dampening incoming sound.

Weatherstripping fits inside your door frame where the door meets the frame, it can also be used in between the folding sections of your bi-fold door.

To apply the tape first clean the area with a wet towel. This ensures that no debris will prevent the tape from sticking.

Then measure the length of your door and cut a strip long enough to cover the whole area.

Peel the sticky back off the tape and press it by hand into the door/door frame as you work your way to the other end. 

There’s a wide variety of weatherstripping tapes that gets the job done efficiently. The Duck Brand Self Adhesive Foam Weatherstrip Seal (below) is among the best options.

Duck Brand Self Adhesive Foam Weatherstrip Seal for Small Gaps, 3/8-Inch x 3/16-Inch x 30-Feet, 2...
751 Reviews
Duck Brand Self Adhesive Foam Weatherstrip Seal for Small Gaps, 3/8-Inch x 3/16-Inch x 30-Feet, 2...
  • Easy to install for windows or doors
  • Seals out drafts and humidity
  • Keeps out dust, insects and pollen

They come in different sizes from small gapes to extra-large gaps, so you can choose the one that fits you the most.

If you’re looking for a high-end neoprene tape insulation, you can try Yotache’s Foam Rubber Seal Strip Tape (below).

Foam Rubber Seal Strip Tape 2 Rolls 2 Inch Wide X 1/4 Inch Thick, Foam Adhesive Strips Closed Cell...
912 Reviews
Foam Rubber Seal Strip Tape 2 Rolls 2 Inch Wide X 1/4 Inch Thick, Foam Adhesive Strips Closed Cell...
  • ENVIRONMENTALLY FRIENDLY - The foam seal tape is made from environmental protection material, CR foam, Neoprene, which has excellent sealing and resistance to deformation feature, toxic free, can be...
  • MULTIPURPOSE - The closed cell foam strip is weather proof, oil resistance, resistant to corrosion, dust proof, shock-absorbing, buffering, sealing, flame retardant, sound proof, heat insulation,...
  • WIDELY USED - The adhesive foam strips are widely used in various door seal and window insulation, furniture, electrical cabinets, cars, speakers, toys, handicrafts, sports equipments, etc

It has industrial-grade sound insulation, allowing for extra soundproofing. 

Applying Acoustic Sealant

Acoustic sealants are mainly used for sealing partitions, drywalls, and joints. However, there’s no reason that you shouldn’t use them to seal a stubborn crack in your bi-fold door.

Tremco Acoustical Curtainwall Sealant (below) adheres to almost anything. The advanced sealant is basically liquid rubber.

Tremco Acoustical Curtainwall Sealant - 28.7 Fluid Ounce Cartridge
2 Reviews
Tremco Acoustical Curtainwall Sealant - 28.7 Fluid Ounce Cartridge
  • Quantity: 1 - cartridges
  • Color: dark gray
  • Capacity: 28.7 fluid ounces

After you apply it to the crack, it turns into a piece of flexible rubber that prevents any sound from passing through. 

The difference is, it doesn’t harden completely, which is why you can use it on doors. Unlike the previous two methods, this one requires a bit of expertise to work with. 

2. Seal the Gaps Between the Door and Floor

While the previous sealants blocked the incoming sound from gaps throughout the bi-fold doors, they won’t be able to seal the biggest gap in it.

The other main cause of sound leaks is the presence of a gap between the door and the floor. To fix this, you only need to create an airtight condition. 

You can achieve this with the following methods.

By Installing a Door Sweep

Door sweeps come with a strong rubber that acts as a stopper to create the airtight condition you’re looking for. The rubber is a great sound absorber, creating a soundproof seal whenever you close the door.

You can use it alone to decrease the amount of external noise significantly. However, you can combine some of the previous methods for the best results. 

Unlike the previous sealing methods, installing a door sweep isn’t as simple as weatherstripping tapes or other sealants. The project might take an hour or two to complete. 

Additionally, you should bear in mind that it's a fairly invasive method, as you’re going to drill some holes in the door to secure the sweep.

Yet, it offers additional perks, such as blocking the dust and keeping the room cleaner for longer. Moreover, it increases the efficiency of internal heating or air conditioning.

The M-D Building Commercial Grade Door Sweep (below) comes at a reasonable price and pulls off the trick quite well. Also, it comes with its own screws, so you won’t have to worry about that.

Sale
M-D Building Products 68247 1-1/4-Inch EPDM 36-Inch DB006 Commercial Grade Door Sweep, Mill, Silver
268 Reviews
M-D Building Products 68247 1-1/4-Inch EPDM 36-Inch DB006 Commercial Grade Door Sweep, Mill, Silver
  • Fits doors up to 36-Inch wide
  • Seals Gap Up to 3/4-Inch High Between Bottom of Door and Threshold
  • UL Rated

It’s also available in different colors to match your bi-fold door.

By Applying a Door Stopper

If you’re looking for a less invasive way to tightly seal the gap between the door and the floor, you can try door stoppers.

Similar to door sweeps, they’re made of various materials, such as silicone, that absorb sound efficiently.

To install a door stopper under your bi-fold doors, you should do the following:

  1. Clean the area of installation with acetone or alcohol to remove debris and dirt
  2. Measure the length of the stopper needed to barely touch the floor and mark it on the door
  3. Use the hairdryer to warm up the area of application to above 75 °F (23 °C)
  4. Slowly peel the back paper as you tape it to the closed door to the marked area
  5. Apply pressure every now and then for the next 48 hours

There are also these removable stoppers from deeToolMan:

deeTOOL MAN Door Draft Stopper 36” : One Sided Door Insulator with Hook and Loop Self Adhesive...
1,188 Reviews
deeTOOL MAN Door Draft Stopper 36” : One Sided Door Insulator with Hook and Loop Self Adhesive...
  • ✔ONE-SIDED UNDER DOOR DRAFT STOPPER! Fits door up to 36” and will close gaps of up to 1.3”. Materials made from sturdy and durable Styrofoam with luxury fabric attached.
  • ✔ENERGY EFFICIENT & NOISE REDUCTION! Cold air stays out and heat stays in. It’s also great for blocking out dust, sand, light and insects. For harsh winters and noise reduction, add draft blockers...
  • ✔EASILY GLIDES ON ALL FLOOR TYPES! Works well on tiles, laminates, wood and stone. It can be used even on uneven or carpeted floors!!

They’re installed the same way. The only difference is that you can detach them whenever you want.

By Applying Foam Stopper

Instead of adhesive silicone stoppers, you can try USUKUE Twin Door Foam Draft Stopper:

USUKUE Twin Door Draft Stopper, Under Door Bottom Seal Strip Noise Blocker for Door Insulation and...
25 Reviews
USUKUE Twin Door Draft Stopper, Under Door Bottom Seal Strip Noise Blocker for Door Insulation and...
  • Simple Twin Door Draft Stopper : Our Twin door draft guard helps you get rid of the door drafty. The door draft blocker is easy and fasts to cover your doors gap help keeps the room temperature and...
  • 42 Inches Length Adjustable : Our twin door draft guard made of quality cotton fabric cover filling with EPE foam. 42 inch length easy to cut to fit most size of doors, such as 30, 32, 36 and 42 inch...
  • Twin Stoppers Design More Efficient and Durable:Two side of seals stop the noise, dirt, dust and drafty side by side, which can provide better block effective. High quality washable fa material...

What’s brilliant about this stopper is that it’s simpler to apply than the silicone ones.

You only need to cut them to the size of your bi-fold door and slide them under, be aware that these offer the least amount of sound resistance out of all these door stoppers.

3. Use Soundproof Blankets

Dense soundproofing blankets are among the easiest ways to soundproof your bi-fold doors, as you only need to hang them on the back of the door with hooks. They also give you the option of removing them whenever you want.


Vocal Booth To Go is the best place to buy soundproof blankets from, they have a huge range to fit all shapes and sizes of walls and they have impressive NRC ratings of up to 0.95 meaning they can absorb up to 95% of sound.


Despite their merits, they have their problems. For example, they’re noticeably heavy, which makes them a bit annoying. Also, they block the lights which is a common side effect with the next method as well.

4. Use Soundproof Curtains

Soundproof curtains are heavier than regular curtains.

They work by closing the gap between the door and the ceiling with dense material, which helps dampen incoming noise.

Unlike the previous methods, this one also dampens the echoes in the room, which makes the room’s ambience more pleasant. Moreover, they serve as a decorative touch in the room as well.

You can view some of the best options below. As a rough guide the heavier the curtain the more effective it will usually be.

5. Apply Soundproofing Paint

Also known as “Acoustic Paint”, soundproofing Paints reduces background noises somewhat compared to regular paint.

Their main ingredient is a noise-absorbing polymer that dissipates external noises.

Acousti Coat - Sound Deadening Paint - 1 Gallon
19 Reviews
Acousti Coat - Sound Deadening Paint - 1 Gallon
  • Dampens ringing and tinning noise in metal structures
  • Environmentally friendly and non-toxic
  • Can be applied by brush, roller or spray (use a hopper spray gun)

6. Replace the Glass

If you’re not satisfied with all the previous methods, or your glass panels are ultra-thin, replacing the glass sheets are your best bet. 

This is by far the most expensive method to go for, so you should expect to splurge some cash to achieve the sought for tranquillity.

Aim to get at least double glazing in your bi-fold doors as this creates an airtight seal between the two panes which makes a significant difference to sound transfer.


What Are the Benefits of Bi-Fold Doors?

Bi-fold doors are also known as “folding doors”, “room dividers”, and “sliding doors”. The reason behind their primary name is that they can fold either in or out to allow air circulation inside the house.

One of their benefits is that they’re great options to light up a room, as they’re usually glazed with a large glass panel. In addition to sliding or folding the door open, you can also stack them against the wall to boost the space in the room.

These doors are particularly great in dividing multiple sections in houses. Similar to accordion doors, you can use them as entrance doors that split the space between a living room and a kitchen.

In such case, they’re called “internal bi-fold doors”. You can use them to cover particular sections inside your house. 

The external bi-fold doors are those that usually lead to your backyard. Since they’re out in the open, they’re usually made to endure the harsh weather conditions. 

Bifold doors are made of a wide variety of materials, including wood, aluminum, and uPVC. Each one of these materials has its own properties. However, they’re notorious for leaking noises.

Why Do Bi-fold Doors Leak Sound?

The main problem with these doors is that they’re usually hollow on the inside. As a result, it’s very easy for sound to leak through them and into your house.

Also due to their multiple folding panels, they often have more gaps in them than a set of standard double doors would meaning more space for sounds to leak through.

This may not be a huge issue if you’re living in a quiet neighborhood. However, if you live in a noisy area it may keep you awake at night.


Wrap Up

There you have it. A thorough guide that runs you through the best methods to soundproof bi-fold doors efficiently.

As you can see, the methods vary significantly, so you can use the ideal one according to your likings. Moreover, you can mix some of these methods together for the best results!

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Welcome to Soundproof Panda!

My name is Dan and I live very close to an internationally famous stadium which generates an awful lot of noise that I'd rather block out!

This site is my place to share what I've been learning on my soundproofing journey.