Author Topic: Freestanding cinder block garage studio to be  (Read 683 times)


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Freestanding cinder block garage studio to be
« on: August 15, 2016, 05:29:33 PM »
Hello Forum,

Since this is my first post, I'll go ahead and introduce myself. My name is Chris, I've just graduated from university, I have been a recording artist for going on fifteen years now, and I'm finally realizing my efforts, and converting a back yard cinder block structure to a studio space for recording and rehearsal, to be a home base for my sound company. I don't want this post to get out of hand in length, so I'll get right to the meat n' taters. I've done my searching, and thus far have not found any threads pertaining to my specific building construction type.

The building as stated above is a Cinder Block structure around a concrete slab. Wood roof, rafters are 24" at center with a 2x10 (I think) main beam. The internal dimensions of the cinder block walls are 18.6' x 29'-at the garage door opening. The ceiling/roof main beam lowest point is 10'10", making the under side of the roof at 11' 4" (6 inches of main beam visible) at the peak. The following image is a 2d illustration of my planned construction - a structure within the existing one, wood stud, resilient channel, 2 layers drywall with green glue between (if budget allows it). And of course copious amounts of sound caulking.

I found a great resourceful website  carried on my research there as well as other sites like this one. I understand I need a 2 leaf system to best mitigate sound exiting the building.

Question 1:

Does a cinder block wall count as just one layer in the system?

These cinder blocks are the cinder block you assume it is, with the rectangular hollow figure 8 shape. So it is the air inside the cinder blocks I'm worried about potentially creating a 3 leaf system.

Question 2:

How do I go about building the inner ceiling?

I think I have a grasp on it, but, my idea conflicts with the premise of decoupling the inner and outer shells. The image here is what the ceiling looks like at present.

Looking at the ceiling as is, and with my design above, my plan for the future ceiling is to create a alternating stud (rafter) 2 leaf system by mounting new ceiling rafters at the 12" half way point between the existing rafters, atop the new inner stud wall at the one end, and afix the top end directly to the existing main beam. R19 in the air gap, and of course the two layers drywall separated by green glue.

Question 3:

Can I delete my ceiling joists?

I know you all are sound proofing people and not structural engineers necessarily (unless you are!) BUT, the existing ceiling joists are cramping my style big time. I wish to create a cathedral ceiling style shape by either eliminating all the joists or shorten them and push them toward the main beam. I prefer deleting all of them. I continue finding myself at this question, because everything I can find on the subject is referencing 2x4 stud wall construction and not cinder block construction. I understand the basic physics behind the fact that the long walls supporting the roof can lean outward from the weight of the roof, but, I just cant find the answer to whether the much-stronger-than-wood-frame cinder block construction can bear the weight of the outer roof without joists running across my entire space. What complicates my quest for answers is that the supports on the ends of the garage are both indicative of cathedral style support directly beneath the main beam, as you can see:

If you are so inclined, I created a sketchup to create a visualization. it is a graphic representation, not extremely precise.

Thanks for any help.


Randy S

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Re: Freestanding cinder block garage studio to be
« Reply #1 on: August 15, 2016, 09:58:11 PM »
1.Hollow cinder block is porous and would need to be sealed so it can contribute to the mass, we can avoid the triple leaf by simply adding mass and building new framing not in contact with the block.

2 and 3. if your willing to loose some of the height lets get the ceiling system out of the equation because we still need to finish equal mass past the cinder block and then we can cap the room so to speak.

I will be more than happy to assist you with your project. I have done a few rooms like this before and there is a lot of detail involved.
Give me a call direct and lets discuss particulars and options.

Randy S.
Randy Sieg

Super Soundproofing Co
Ph. 760-752-3030