Need soundproof: Changing interior hollow core door to solid core, or exterior door?

aminus21

Hello all,

A follow up from this post:
Adding door in hallway between two rooms

We ended up adding a prehung 30" hollow-core interior door between the two bedrooms. However, the door provides NO soundproof at all, it's very easy for the kids to stay awake when a conversation is being held in the adjacent room.

We want it to be sound proof, so the thought of getting a fiberglass exterior door came to mind. Is that overkill? Are they any more soundproof than a solid core interior door? Also, there won't be much traffic going between the two rooms, so the extra weight of the exterior door would be ok.. we just want it to be very sound proof. I'm also thinking of adding some insulation behind the drywall above the door..

Lastly, if we're going from hollow core so solid-core or even from hollow core to exterior door, would we need to change the door frame or hinges?

Just Bill

Not sure how much soundproofing you need, but hollow core definitely won't do much. An interior solid core door may be somewhat better. A foam filled hollow core door might be better. As to the door framing, it should be the same as all door frames, in that is will support whatever is hung there.

aminus21

I need as much sound proofing as possible. The doorway won't get much cross traffic, so I'm not worried about it being too heavy or sealing too well. I'm willing to shed the extra $$$ for something that's sound proof. Also looking into the idea of adding some insulation between the drywall above the door, if that would help..

aminus21

How does MDF compare to solid wood?

http://www.homedepot.com/Doors-Windo...atalogId=10053

http://www.homedepot.com/Doors-Windo...atalogId=10053

pyper

First, "soundproof" doesn't exist. What you want to do is reduce the sound. In particular, you want to reduce specific sounds (conversation).

There are two kinds of sounds in buildings.

1) air born.
2) structure born.

The second, you can't stop with a door. Examples might be hitting the wall with your fist -- it vibrates the studs, the studs vibrate the other side of the wall, and the sound comes out.

So what's happening, in part, is your voices are going down the hallway, and then under and around the door.

It doesn't matter what kind of door you put up, if you leave air gaps under and around it.

Some of the sound that's going down the hall also strikes the door, and is transmitted through it (becoming structure born for a moment). A more solid door will help stop this portion of the sound.

I got a door for my practice room made by Masonite. It's designed for sound mitigation. I think it was over $100; maybe over $200. It works, but I installed it so that it closes really tight. You can also buy solid doors at Habitat for Humanity resale stores for a lot less. Exterior doors can work well too. But again, only if they close tightly on all 4 sides.

Note that if your room has a heating duct into it, that:

a) Sounds travel through duct work just as easily as under doors, if the runs aren't too long, and
b) If you seal the door, and if your room doesn't have a separate return in it, then you will have sealed off the return path, and the room will neither heat nor cool when the door is closed.

So a good first step is to put felt weatherstripping on three sides, and a rolled up heavy towel on the bottom, and see if you still have a problem. If so, go from there.