A lot of noise gets into the room through gaps, cracks, holes, and other openings in the walls, doors, and windows or between them; the tiniest will let in a substantial amount of noise pollution from outside. Impact noise can also transfer through the vibration of the window or door and the surrounding wall, floor, or ceiling. The objectives of soundproofing or noise reduction should therefore include sealing all openings through which sound waves can be transmitted into the room, increasing the density and mass of the insulation so that sound has a tougher time penetrating the fortress and/or dampening the intensity of the noise.
We compiled a few methods we have successfully used to soundproof a room from exterior noise as a guide for people facing similar noise challenges. These sound insulation ideas are straightforward, and you can easily implement them in the home. Read on, so you don’t have to learn through your own uncomfortable experiences.
Soundproof The Windows
Windows are not the best sound barriers; glass especially has a low sound transmission class (STC) rating, meaning it’s poor in attenuating airborne noise. They are, however, important because they allow natural light and fresh air into the room, which is why a lot of thought and resources are directed towards soundproofing them. There are many ways to approach this:
Reinforcing Window Panes
Do this by deploying window inserts that act as a second skin. They come in the form of a glass pane with an airtight seal so you can create a secondary barrier. Separate the second pane from your original window pane by insulating airspace to block unwanted noise.
They are highly effective because the gap between the two skins significantly eliminates transference of impact noise as the combined mass of the two window panes further impedes airborne noises from getting into the room. They can be custom-fit to any window size, and the more airtight the seal between the 2 panes is, the more effective they are in blocking outside noise.
You can add extra window panes to block even more noise transmission, making your window double or triple-paned or more, depending on the level of insulation you are targeting. This method of reinforcing window panes can, however, be expensive. So are the supporting window panes, especially if the windows are huge.
Window Plugs
These are inserts fitted on the inside of window frames that prevent air, noise, and light from entering and exiting the room. They are great acoustic and thermal insulators because they seal any gaps that may allow heat and sound transfer. The mass and density of the sound-absorbing materials decrease the movement of sound, and the airtight seal creates a dead space that traps and dissipates low frequencies.
- Acoustic panels
They soundproof the room by absorbing soundwaves and blocking noises permeating into the room. When soundwaves strike these panels, the fibers or soundproofing foam pores vibrate, creating friction between them. This friction converts the sound energy into kinetic energy (heat) of the fibers and pores in motion, which dissipates quickly, dampening the intensity of the soundwaves and killing the noise. The airtight-fitting dense mass also plays the role of blocking noise from entering or exiting a room.
There are numerous options to choose from in the acoustic panel department, from acoustic foam panels, neoprene foam panels or mats, stone wool panels to fiberglass panels. The higher the density and the thicker the panel is, the better it performs in soundproofing.
- Viscoelastic Materials
Viscoelastic materials don’t absorb sound but are great for damping soundwaves through reflection and diffusion, reducing the overall resonance. Their strengths are viscosity, which is resistance to flow and noise transfer, and elasticity which allows them to deform and revert to their original shapes. They flow with the force of the soundwaves, deflect them and return to their original shape without letting any of it through. They dissipate noises on contact, so they have no chance to build up. For the best results, you should deploy them with an allowance to flex so they can effectively diffuse the sounds.
The most common viscoelastic materials in soundproofing are mass-loaded vinyl (MLV) and green glue.
- MLV works as a reflective barrier, meaning it can confine sound within a space or prevent it from getting in from adjoining spaces. It reduces sound resonance through reflection and diffusion.
- Green glue is a malleable damping compound applied between two rigid materials that dissipate structural vibrations caused by sound waves traveling through ceilings, walls, and floors.
Window plugs for large windows require some structural support to hold them in place. Common supportive materials include plywood, medium-density fiberboard (MDF), and oriented strand board (OSB). Unlike OSB and plywood, MDF is heavy, and the mass supports the window plugs in blocking sound.
While all the above materials make decent soundproofing window plugs, their combination provides excellent sound absorption and reflective properties.
Window plugs are not always practical. They soundproof the window and inhibit thermal loss, but they also block the view and prevent natural light from coming in.
There are permanent and removable versions of window plugs. Removable window plugs address the limitations of natural light and blocked views and allow you to use the window for its intended purpose whenever you don’t need to be soundproof.
If you go with the permanent window plug, consider adding reflective film to the side of the plug that will be propped up against the windowpane to reflect sunlight away from the room. Otherwise, there may be undesirable heat buildup between the window pane plug. The removable plug should come with sturdy handles so that you can mount and dismount it; remember, an effective window plug fits snugly to create an airtight seal.
Another concern will be the aesthetic impact of the naturally dull plugs. Address this by using solid colored plugs or investing in print fabric to adhere to the back of the plug that blends with the theme of the room.
Soundproof Curtains
These drapes are thick and heavy material, which when applied correctly, is effective in blocking out sound. They hang over your windows as shields from cold drafts, light, and more importantly, outside noises. They are easy to install and are designed to complement your interior design, which makes them a convenient way to soundproof a room.
Look for curtains with extra insulating layers because mass blocks and absorbs more sound. The curtains should also run from the ceiling to the floor and cover a few inches past the sides of your windows to enable them to seal off the windows.
Consider ceiling-mount brackets so that the curtains can achieve the ceiling to floor coverage. Regardless of how you mount it, the curtain rod or tracks should be heavy-duty enough to bear the heavyweight of the curtain. Use one continuous curtain when you can and if the window is too wide for that, ensure there is no gap left between your curtains; they can overlap for good measure.
These acoustic curtains reduce the reverberations of sound, hastening its natural decay. They are great with airborne sounds but are not as effective against low-frequency sounds and will therefore not be adequate for completely soundproofing a room without backup from other quarters.
These acoustic curtains come as double layers of triple woven fabric with double the sound absorption effect of regular curtains. They have a generous valence which ensures there are no gaps above the curtain rod through which sound waves can penetrate the room.
Weatherstripping Windows
This process is sealing air leaks through the gaps between window sashes, sills, and frames via the check rails or any other opening. Sound travels through air, and the slightest gap can have a huge impact on soundproofing. The options for weatherstripping windows are limitless; some are permanent while others are temporary fixes. The seals are made of cork, rubber, plastic, or metal and are deployed in different ways.
Permanent Weatherstripping Methods
- Tubular Linings
These are flexible vinyl or rubber seals that come as coils that you can fit to size and attach to the underside of window sashes using staples, tacks, or adhesive. They are applied outside where they conform to the contours of the uneven surfaces. Don’t paint them, as doing so will make them stiff and lose their flexibility.
- Interlocking metal channels
This solution involves 2 separate pieces of metal, one fitted on the moving window sash and the other on the jamb or sill. The pieces fit into each other to form an impenetrable seal when the window is closed. Installation involves cutting of metal, and accurate alignment is paramount, we would advise that you leave it to a professional. You can, however, realign the pieces using a putty knife, a pair of pliers, or a screwdriver once they have been installed if they get out of shape.
- Spring Metal Strips
These are also referred to as V-channels or V-strips and are commonly used to weatherstrip double-hung windows. The stripping comes with stainless steel, aluminum, copper, or bronze finishing and is usually packaged in rolls along with the brad nails used to attach it.
The sash is removed, and the V-strips tacked into the channels on which it slides up and down. It is flared out so that the metal can create enough tension with the sash to seal the window when it’s closed.
Temporary Methods
- Plastic Sheeting
These are ideal when you don’t want to or are not allowed to make any permanent changes to the house. You can staple it to the window’s exterior, and if you stretch it well and trim the excess material off accurately, it will be almost invisible. Keeping the air out also blocks soundwaves from accessing the room.
- Rope Caulk
This caulk is in the form of a cord applied on the seams between the window sash and casing to keep out drafts. The window is closed while installing, and you need to apply some pressure to make the seal airtight. You can easily peel it away when it’s no longer required.
- Pressure Sensitive Foam
These foam strips are available as rubber or PVC sealants and come in rolls of different sizes and thicknesses. They seal out the air when compressed by a door or window and have the bonus of providing a cushioning effect which absorbs the impact of the door or window slams shut, and with it the noise. They often come as self-adhesive foam tapes that are easy to apply.
- Felt
The condensed, matted fibers make it feel thin and heavy so it can inhibit the propagation of low-frequency sound waves, which is why it’s a popular soundproofing choice. It works by dampening vibration and absorbing sound.
Felt can be made from natural fibers such as animal fur, wool, or synthetic fibers, like petroleum-based acrylic. Some acoustic felt makers even reinforce them using UV- and weather-resistant EPDM rubber for enhanced flexibility and waterproofing. Felt strips come in a variety of sizes, thicknesses, and colors and can easily be customized to suit your needs.
It is applied using adhesive to prevent sound from transmitting through surfaces like the window, door, wall, or floor. It is also used to fill in gaps for weatherstripping, making its utility in soundproofing versatile.
Soundproof The Door
A significant number of modern doors are hollow inside. This design requires fewer resources, making the doors more affordable than solid core doors. The low density of hollow core doors can’t do much to block out sounds, especially if it is significantly loud.
If you have the resources, you should switch to a dense, solid core door and address this problem wholesomely. This is an expensive venture, and there are often restrictions to the kind of modifications that you can do on the property, so you might not be able to use this fix. Soundproofing the existing door is the next viable approach, and there are many ways of doing it.
Acoustic Blankets
They are affordable and very effective in blocking out outside noises. They hang on the back of the wall, and you can use tacks or adhesive to hold them in place. They are, however, not aesthetically appealing by nature and are used when soundproofing is more important than ambiance.
Door sweeps and Draft Stoppers
These weatherproofing materials block the gap left between the door and the floor. Air gets in and out of the room through this gap accompanied by soundwaves.
The door sweep is attached to the bottom of the door, and it fits snugly between the door and the threshold or floor. It seals the gap when the door is closed. Draft stoppers are also called draft blockers or draft dodgers and function similarly to door sweeps. They are, however, made of fabric and designed to be malleable. They are easily attached and detached from the door.
Weatherstripping the door
Air can also get in through the gaps between the door and the floor or its frame. Weatherstripping a door is similar to weatherstripping the window. The only difference will be the length of the material. You can apply the caulk seals, felt, interlocking metal channels, or tubular lining for the same purposes mentioned earlier.
Soundproof the Ceiling
This is especially important when you need to soundproof a room from outside noise, and the pace above it is in use. Most of the noise coming through the ceiling will be in the form of impact noise from footfalls and objects dropping on the floor above the room. The most effective way to reduce these noises is by decoupling the room from the ceiling.
Drywalls and Drop Ceilings
These are deployed under the ceiling to act as an extra barrier against soundwaves. For best results, you can spray green glue on the drywall with a caulking gun or deploy MLV in between the drywall and the actual ceiling to absorb the vibrations. This solution is costly and might require some expertise to apply.
If you need to soundproof a room from outside noise, use these methods together. None of them is efficient on its own, but any combination will boost their efficiency.
