cellar studio wondow soundproofing

[karambos2]

Hi there,

I have a small studio in a celler apartment. There's one double-glazed window in the control room, outside of which is a kind of drainage and lighting "box" measuring approx 4"x4"x4" where the light gets in and the leaves gather in autumn. The top of this box is a grid at ground level where the rain can and does get through.

I made a jpeg (graphic) of the window from inside the studio and a cross section of the "box" and to save on your server space I put it up on mine. Here's the link:


My question is - how do I soundproof it?

I thought about doing the following and was wondering if you thought it a good idea. I want to do two things
1) treat each window individually by screwing in two 0.5 inch (1 cm) thick pieces of plywood, seperated by a 2 inch (5 cm) gap filled with Rockwool, over each window
2) put sandbags in the external "box" area covered with a polythene sheet to keep them dry.

I'm grateful for any advice

[TexRoadkill]

A few inches of rigid fiberglass and a plywood cover attached to the wall should keep in/out most sound. If one side isn't enough then do it on both sides. Generally speaking you should get the best isolation by having two rigid surfaces with insulation on each side and a single air cavity in between. By putting plywood on both sides you may actually have worse RTC because you will havce a 3ply barrier.

You might also put some plastic over the windows and caulk the edges well for an airtight seal.

[karambos2]

hi there,

thanks for the reply. Just a couple of quickies:

1) I'm a little averse to using fiberglass as I've got bad lungs and I've heard that *some* people (not all) can react to the fibers that are given off. Can you recommend another material? I assume any rigid material will do.

2) what's RTC?

Thanks

[TexRoadkill]

Rigid fiberglass doesn't flake off as easily as the regular fiberglass insulation. I'm not really sure what would be next best.

I meant to type STC - Sound Transmission Class (I think). The higher the STC rating the less sound gets out. If you search for threads in this forum by Knightfly he has some good posts on basic soundproofing construction with good visual aides.

Ethan Winer and John Sayers have websites with good info also. You can find a link on any of their posts and they post here often.