Wall construction

Hi gang. I'm looking to build a single-room studio in my garden, primarily so I can play my Drums and Bass and perhaps a little recording for my own purpose. I'm ready to start the build as soon as I button down the details. I have been researching but am left uncertain on the following points. As shown on the left-hand image, I was intending to simply poor the foundations, and build a cavity wall (100mm bricks/100mm cavity/100mm blocks) but after reading one of Rod Gervais' previous posts, I have interpreted that this is not the M-A-M I am looking to achieve as the inevitable sloppy mortar-work and brick-ties will couple the two walls together, resulting in a single leaf system. Also, the concrete floor is coupled to the internal wall, so this design is very bad, right ? 1) Would I be better building a single skin wall from Hollow Concrete Blocks, separating the poured slab from this wall by means of an upstand and then building a studwall on this independent slab (as shown on the right hand image) ? 2) Would the concrete blocks need to be filled with anything, or left hollow ? 3) Is there any way that I can construct the studio using convention bricks instead of concrete blocks ? ( The reason being is that concrete blocks are ugly and as the studio is clearly visible from house, the wife will go mad. I don’t really want to have to pay for someone to render it afterwards). 4) Am I correct in thinking that I might be going overkill will the walls, as the room is only as good as its weakest link. In this case it will be the ceiling. I was thinking of 2 layers of OSB for the actual roof covering. I was going to beef this up by stretching rafters across the internal wall so it can hold a couple of layers of plasterboard across it, with rockwall above this. Thanks for any criticism/advice you can spare the time to write. Regards Steve

Hi Steve. Still waiting for answers? 100mm bricks/100mm cavity/100mm blocks this IS M-A-M Now to your questions: 1) first part: No. second part (separating the poured slab): Yes! (-> keyword: decoupling) 2) Yes. They're better to be filled. (-> keywords: hollow bricks) -> http://www.johnlsayers.com/phpBB2/viewtopic.php?f=2&t=8574 3) you can use whatever you want and whatever is to code... The heavier the better. Bricks will be fine. (-> keyword: brickwall) 4) you're correct with your assumption concerning the weakest link. But maybe someone with more knowledge can chime in and lead you to the right direction. Hope that helps, cheers carsten

"but after reading one of Rod Gervais' previous posts, I have interpreted that this is not the M-A-M I am looking to achieve as the inevitable sloppy mortar-work and brick-ties will couple the two walls together, resulting in a single leaf system." And that is why Mr. Gervais' said it. So it would be known that this is difficult to do and in effect becomes one leaf. Because of the connections that you quoted, brick/block ties and mortar dripping this potential two leaf is short circuited and becomes one. A higher rated one, but still one leaf. If this was something you are still considering, build the wall and fill the void as you do it. This way you know what you have, one deep leaf. If you have the means, the picture on the right hand side would be the better build. A hollow block filled with sand will be better than filled with concrete. The dry sand has the density but also allows flexibility.

oh. Sorry for posting false information! :oops: I should better read twice before answering. Nevertheless, I hope you all had a merry christmas. Regards, Carsten

carsten_d wrote:

oh. Sorry for posting false information! :oops: I should better read twice before answering. Nevertheless, I hope you all had a merry christmas. Regards, Carsten

I had to look at it a few times myself :)

The construction in the first figure will be fine or your application. It will give you better isolation than shown by the lower line in the attachment. The lower line test had the two leafs on a common test frame, with the leafs attached to frame on al four sides (top, bottom, left, right). It is taken from NRC IR 586. In your build you would only have the bottoms connected, giving less coupling between the leafs. Hence better performance than shown in the Would separate isolated footings give greater isolation? Yes. Is it needed in you case? No. You will have greater than 37 dB TL in every at every frequency above 63 Hz. That is a very respectable performance. For an idea of how good it is, compare it to one of the best drywall constructions from NRC IR 761. The issue with music isolation is the low end.

I interpreted the left hand picture as a three leaf.

xSpace wrote:

I interpreted the left hand picture as a three leaf.

Your interpretation is correct. The MAM of the third lea is so hi that the effect is not significant or music isolation. It is not meant as daunting, but Sharp has been referenced before in threads that you follow and has the background for it. You are right, just a matter of the specific mass and space involved. Andre