Reducing sound in a concrete room

Background: My friend is quite sensitive out noise as he is falling asleep. His bedroom shares a common wall made out of concrete with the attached house next door. His wife sleeps in another room in their house, and walks around, making some noise. He already uses a white noise machine to somewhat muffle sounds.

They have some foam from a music studio, and are looking to put that up on walls to help deaden the sound. They had a cheap internal door into the room,and will replace it with a solid wood door.

I’ve done some googling on sound reduction, but would like to know if anyone has had any experience with this.

The key is not to put the foam in direct contact with the wall. Set it up 1/8 inch or so in front of the wall. If there is direct contact between the materials then sound will tend to travel through. Any material that increases dead air spaces between him and the noise will be helpful.

Also think in terms of texture. Baffling traps the sound so that it bounces within the foam or fabric instead of out toward the ear.

A good solution for sleeping is a four poster bed with a heavy curtain hung around it. If sound is coming from the unit above, or traveling from the walls to the ceiling, then a canopy can also help. Velvet (with the plush side toward the noise) and thermal materials are great for this.

A site with some helpful stuff:

There is also a psychological aspect to this though. Yes, there are sounds so intrusive that they must be blocked out in order to achieve good rest. But if he’s just not sleeping well, no matter how quiet you make it he’s going to hear the next quietest sound. In the world’s quietest room, the human mind begins to focus upon the sound of blood rushing through the head and the sound of mouth moisture begins to bother them.

I used to live in a dorm that was mostly pre-stressed concrete slabs. Don’t underestimate the transmission of sound from the concrete to the floor, ceilings, and other surfaces. To reduce sound transmission, you want to “uncouple” surfaces from the common concrete wall. Just putting foam or some other insulating material on the wall won’t do this very well. The floor, ceiling, and other walls are doubtless connected very firmly to the concrete.

How “hard” is the room? The more he can soften it with upholstered furniture, draperies, wall hangings, carpet, and other materials that will absorb sound, the better off he will be.

This is a very interesting idea. I’ll suggest making a sleeping cave for him. He’s got enough sleeping problems that he may go for it. The only problem is that this is Taiwan and it’s hot and humid. Keeping it as the same temperature as the room, without losing the sound reduction would be important.

He’s really sensitive to sharp sounds and not just all sounds. He already uses a white noise machine, as mentioned in the OP.

I believe you are correct, simply putting foam on the walls will help but not completely eliminate the problem. I’ll talk to him about adding more material into the room and see how it goes.

Foam on the walls will reduce reverberation of sound generated inside the room. It will not do much to reduce sound transmission through the walls. For that you’d need some sort of limp barrier material, such as mass loaded vinyl sheet.

Your friend will want to verify whether this material is fire-resistant.
Here’s a small demo of the difference that flame-resistant materials make. For a more graphic demo, here’s the 2003 Station Nightclub fire which killed 100 people, in part because the acoustic foam was not fire-resistant.

The gym at my first school district was, for all intents and purposes, a “cinder block box” that had tremendous noise retention and amplification. We got an expert and they installed a layer of special ceiling tiles under the cinder block ceiling. It helped immensely. There would be a cost factor to consider in doing something like that, of course.

If the floor is tile or wood, just putting a rug down will go a long way to help deaden sound. The shaggier the better. Even if the floor is carpet, adding a rug should help.