A soundproof door is the finishing touch of a soundproof room. A good quality soundproof door depends on the construction and quality of the material. It is important to know what to consider when buying soundproof doors. There are also ways to improve the soundproof quality of regular doors.
What is a Soundproof Door?
A soundproof door is one that is constructed with heavy materials which do not allow sound and vibration to pass through from one side to the other.
Masonite is a premier maker of soundproof doors. They construct their solid core doors with 70% more sound-dampening material than standard hollow core doors. In addition to the solid door construction, soundproof doors feature frames without gaps to keep sound from seeping through the holes.
If you are looking to soundproof a room, doors and windows should be a special consideration as they are often the weakest link. For a soundproof door, you can either buy a soundproof door or try to retrofit a standard door.
Sound Transmission Ratings
One of the most important considerations when looking for soundproof doors or materials to help you soundproof your door are Sound Transmission Class (STC). This number ranks materials or products according to how well they block sound. The higher the rating, the better the sound blocking qualities of that product or materials.
|STC||What can be heard at this level|
|25||Soft speech can be heard and understood|
|30||Normal speech can be heard and understood|
|35||Loud speech can be heard and understood|
|40||Loud speech can be heard, but not understood|
|45||The threshold at which privacy begins|
|50||Loud sounds can be heard, but are very faint|
|60+||At this level, good soundproofing begins. Neighbors generally are not disturbed by very loud speech from inside.|
Solid core doors will have a higher STC rating than hollow core doors. On a practical level, retrofitting hollow doors is never going to be the same as buying a solid door. Yet, there is some improvement that you can make to create a better barrier.
Options for Soundproof Doors
When choosing a soundproof door there are a variety of materials and constructions that you can consider. A good STC range for soundproof doors is between 42 and 52 which will include the door and the frame.
Soundproof Door Construction Type
- Hollow Core Door – A hollow core door features two outer panels glued together on a wood frame. These panels cover an interior that is made from light corrugated material that helps the door retain its shape. These doors are not substantial and allow sound to vibrate through the panels. Some hollow core doors like those of MDF have a STC rating from 20-25. Yet, there are other acoustical hollow door systems that have higher STC ratings between 32-66.
- Solid Core Door – Solid core doors have two exterior panels that fabricators place onto an outer frame. These doors feature a mix of materials in the core like wood particles and glue that are heavy and solid. Doors with wood particle cores have an STC of 30-35. Doors with wood block cores have an STC of 55-60.
- Solid Wood Door – Solid wood doors have wood panels, stiles, and rails. Certain doors use just solid wood and others are a mixture of solid wood and MDF. Depending on the type of wood, some solid wood doors block sound better than others. These doors have between a 35-45 STC rating.
Different materials transmit sound in a variety of ways. In general, the denser the material, the less that material will transmit sound. Fiberglass and aluminum doors have lower STC ratings as these materials are lighter. Steel, wood, and certain types of MDF are denser and have less sound transmission. More important than the type of material is how the materials are how the materials are put together and fit within the door frame.
Door Frame and Hardware
The most comprehensive soundproof door solution will include the frame in the design. This will help mitigate issues with air gaps between the frame and the door and create the best seal possible. The right hardware will also prevent air gaps in the door.
The Bottom Line Regarding Soundproof Doors
When you cut holes in the wall to create openings for doors, you are downgrading the STC of the wall. Therefore, it is vital to fill the hole with the best door for soundproofing.
For the most seamless option, look for a complete door system including the door and the frame with a high STC rating. Make sure that it fits into place with no air gaps. Include an acoustic threshold if one is not included in the system for the tightest seal around the entire door frame.
Be aware of installation errors that may result in lowering the STC of the door. Pay attention to any spaces between the door/door frame and the existing wall. Install a heavy header above the door in order to increase mass in the wall above the door.
How to Soundproof a Door
Trying to soundproof an existing door is difficult. But, you can improve the soundproof quality of any door by following certain steps.
Acoustic Door Sweep
People place door sweeps on the bottom of doors to help close the gap between the door and the floor. Manufacturers make acoustic door sweeps from specialty acoustic material that keep out sound. When you install the door sweep for acoustic purposes, place the door sweep as low to the ground as possible. Any gap will allow sound to filter through it.
Install a Threshold
Similar to an acoustic door sweep, you can install a threshold on the floor below the door to close the gap. This is like a standard threshold but it has a raised middle section of rubber. This rubber section is able to create a tight seal with the door to minimize sound leakage.
Companies like QuietRock make a product called acoustic caulk. They formulate this product so that it doesn’t shrink over time but stays pliable. This ensures that no gaps form over time. Use this to caulk around any gaps between the door frame and the surrounding wall.
Air gaps around the door make it less sound proof and less energy efficient. You can apply acoustic weatherstripping around the door frame and the door if there is a gap of any size around the door. Weatherstripping, like this option from CIKKIIO, is easy to apply and effective.
Cover the Door With MLV or an Acoustic Blanket
Hanging mass-loaded vinyl (MLV) or an acoustic blanket over the door can be an effective way of soundproofing doors. Of course, this is an impractical solution if you use the door on a regular basis as you must seal the edges to get the best result. Therefore, this method should just be used if you don’t need to open or close the door often or if you must reduce the sound transmission of the door at all costs.
Frequently Asked Questions (FAQ)FAQ
What is the best type of soundproof interior door?
In general, the best soundproof doors have dense mass. Look for solid core doors to get the most soundproof door possible. These can be solid core doors of wood or a composite material. For the most soundproof look for doors that fit within the frame in a way that is tight with no air gaps.
What is the least expensive way of soundproofing a door?
Adding acoustic caulk, a threshold or acoustic door sweep, and weatherstipping around a door will help you to create a more soundproof door at a low cost.
Where can I find soundproof doors for sale?
There are many places where you can find soundproof doors for home and commercial grade use. You can order them from specialized fabricators or from home improvement stores like Home Depot and Lowes. The most important factor is to look at style, construction, material, and STC rating.
What does a soundproof door kit include?
Soundproof door kits include different items depending on the kit. Almost all of them include weatherstripping that you can install around the door frame. Some also include door sweeps or thresholds to close the bottom gap. Be sure to check out the exact components of a kit before you buy it.
A soundproof door will enhance rather than detract from a soundproof room. If you are serious about creating a soundproof space, it is best to buy a door that has been fabricated with certain qualifications. Yet, there are ways that you can make any door more soundproof. There are multiple options you can choose whatever direction you take. Find one that works for your budget and to help your room function best.