Scott DS

Basement Ceiling Insulation

First time poster here- I've been combing through a lot of posts and have really enjoyed everyone's insights and knowledge!

Getting to it, I am very close to starting to finish my basement. Its a two story house (ten yrs old) and the basement only had the foundation walls studded, insulated adn vaporlocked. I am going to build a quasi home theatre room in the main area and have decided to dry wall the ceiling. Due to many annoying pipes and ducts, a good chunk of the drywall will be attached to wood strapping rather than the floor joists. My first inclination was to think that insulation between the drywall and floor above would be a good idea for soundproofing purposes. Talking to some people in the construction business, they seem to think that insulation would not be worth time or expense, and that the dead air space (which would be considerable) would be just as effective for deadening noise.

What are the experts opinions on this? I know in an ideal world, I would be building a room within a room, but my case its not a practical solution. I'd hate to go to all the effort of finishing the basement, filling it with top notch audio equipment, and then have a whole house rattling experience every time I wanted to crank it up a notch or two!

sorry for the rambling message, and I look forward to any responses.

Scott

Cameron Wright

I'm kinda waiting for an answer to this question as well

Buy the best, Cry once

David WS

I'd put the insulation in. I'm working on the doors and trim in my basement/theater right now. (Hung the doors last night.) I insulated the ceiling in my basement and can already hear the difference. The sounds from upstairs are MUCH quieter. I used r-13 unfaced which left a small space in the 2x10 floor joists. This way I had an air gap, which does help reduce sound transmission but not nearly as well as insulation, as well as insulation which will knock down the high frequency transmission between floors. The subfloor and drywall on the outside will help control lower frequency transmissions. This sandwich setup is about as good as a DIYer can do. The insulation can't hurt. Air gaps work only on certain frequencies. The size of the gap determines which frequencies will be attenuated. So the gap between the floor and ceiling will help knock down only certain frequencies not all. Insulation will control a much larger range of frequencies.

I worked on a research project in the past where we were trying to control sound tranmission with different materials. (I actually received two patents for my work on the project.) This is where my opinions were formed on sound this subject. I'm not an acoustic engineer but I've worked with them in the past. One of the things we discovered was using different types (density) of soft insulation in layers will work better that using one thick layer, but that seemed like to much work for my basement.

Dave

Oh, they have the internet on computers now... Homer J(ay) Simpson

Scott DS

thanks for the info Dave. I appreciate it! Good luck with your own project

Scott

KenA

Dave's right on the nose with the varying density suggestion. Different densities will trap different frequencies. The best solution is to isolate the room completely (aka room within a room), but if you can't do that, insulation, resilient channel, and drywall will go a long way. It won't stop everything, but it stops most sound.

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