Question for Rod Gervais

[Rabbit]

Hi Rod. I have figured out that you have considerable knowledge in sound proofing and I appreciated your advice. Would you be so kind to answer a few questions that I have? I have switched back to the "double wall" theory again for my back porch studio. Here are my questions:

1. Does it matter that the inside wall attaches to the outside wall at the top? It seems to me that it must attach somewhere.

2. Is a one inch space between the bottom plates (2x4s) sufficient? (I'm not sure if this would be called a 1" air gap or an 8" air gap?)

3. I currently have 2" thick rockwool in the outside wall. I would prefer to live with that amount of insulation unless doubling it would make that much difference. I have read that the amount of the insulation is not that revelant. Can you comment on this?

4. If I do need to add more insulation, would it be possible to use all the trimmings and cut peices that I have or is it neccessary to use solid pieces between the studs?

Thanks.

[Rod Gervais]

Originally Posted by Rabbit

Hi Rod. I have figured out that you have considerable knowledge in sound proofing and I appreciated your advice. Would you be so kind to answer a few questions that I have? I have switched back to the "double wall" theory again for my back porch studio. Here are my questions:

1. Does it matter that the inside wall attaches to the outside wall at the top? It seems to me that it must attach somewhere.

It does have to attach to something somewhere - but this can be done through the use of isolating clips that stop the transmission of sound (flanking noise) from one wall to the other.

2. Is a one inch space between the bottom plates (2x4s) sufficient? (I'm not sure if this would be called a 1" air gap or an 8" air gap?)

The greater the air gap the better - an inch would be the minimum I would reccomend.

3. I currently have 2" thick rockwool in the outside wall. I would prefer to live with that amount of insulation unless doubling it would make that much difference. I have read that the amount of the insulation is not that revelant. Can you comment on this?

There is some value in installing insulation in each cavity - and thus damping (sp?) the material in each wall....... I honestly do not know the extent to which this will effect the over all wall performance - however I will look into this and see if I can find the data.

4. If I do need to add more insulation, would it be possible to use all the trimmings and cut peices that I have or is it neccessary to use solid pieces between the studs?

Well - seeing as you really do want the air space (that 1" or better space) to remain air space - it seems it would be difficult to keep the pieces in place.

If you can figure out a way to gaurantee that the material stays in place - it would not make a difference.

By the way - thanks for the kind words....... but remember there are a lot of people here you can get some good advice from.

Sincerely,

Rod