Soundproofing a door is actually a quite easy to do and probably not as expensive as you think. Nine times out of ten, simply sealing the air gaps around the door does the job very well.
The door is always one of the first places we address about when one is concerned with the amount of sound entering or leaving a room. Like water, sound will travel via the path of least resistance which is almost always around the perimeter of a door.
As an experiment, have someone stand outside your door and tell them to speak in a normal conversation voice level. Place your ear along the sides of the door as well as along the floor. If you can hear them clearly, which I assume you will, ask them to lower their voice. Continue asking them to lower their voice until you can not hear them anymore. You will be surprised as to the amount of sound that leaks out from around the seemingly invisible cracks in the door. The first step in soundproofing a door is to eliminate as many air gaps as possible.
A handy technique we like to use is to first turn the lights off in the room, and leave a light on in the hallway – or use a flashlight. The areas that leak the largest amount of light are also going to leak the largest amount of sound. Concentrate on those areas first.
There are many popular door seals that can be ordered in a kit to seal up the gaps around the entire door. Usually door seals are made out of neoprene rubber, so the thicker the door seal, the more soundproof the seal is. Which thickness you choose is up to you and should be decided on the importance of confidentiality as well as the severity of the problem before the kit is installed.
If sealing the edges of the doors is not sufficient, your next option would be to explore custom acoustic panels for the door or replacing the door completely with a more soundproof option. These are a bit more expensive and we’ll dig deeper into them in future blog posts.