guitar studio in Oslo

I've gathered a lot of information over the past few months from this site. I am building a studio in my basement. I live in a residential area with very little traffic - the most noise comes from neighbors walking in the stairwell directly outside. It will be a TINY space (no helping that) of approximately 186cm x 204cmx 250-320cm (slanted wall). The dimensions are nasty, but since I'll be playing classical guitar, the sound will not be sooo bad (or so great). The room will be used for recording, and mostly for rehearsals. In a sense, I'm looking mostly to isolate the outside so I can hear myself play. Two of the wall surfaces is this faux-concrete - the outside looks like concrete and the middle of the blocks has a flakyness to it. The other two surfaces will be 2 layers (now to standard measurement) 5/8" gypsum with green glue in the middle. On the interior of this, I plan to construct a "room-within-a-room" applying 2 layers of gypsum+green glue on the interior walls creating the 2 leaf system between the 2 separate frames. The floor is concrete (dry), and I really want to build this as little as possible to keep as much headroom as possible. The ceiling will still need to be determined, since the ceiling joists supporting the upstairs bedroom are 2"x8" spaced 21"-24" inches apart running about 16'. I will perhaps need more support for the joists to run one layer of gypsum/backer rod underneath the floorboard, then insolation, then RC leading to two layers of 5/8 gypsum+green glue.... I'm estimating 9lbs, psf in total added to dead weight to the ceiling. Any advice here will be greatly appreciated. The ventilation will be by air exchange using the "Dead Vent" (exterior baffle box) method http://www.soundproofingcompany.com/blog/archives/71 posted earlier by "MTLA" in his discussion with Glenn. I'll have 2 baffle boxes on opposites end of the studio, each outside the rehearsal room - one vent low and the other high - with a removable exhaust fan that I can change pending on the time of year. (both in green) I purchased one hefty glass door that will somehow need to be negotiated between the two sets of walls. There will be two window areas, one looking outside the basement, and the other looking into the adjoining room, and both times there will be double windows (one window per frame). As for electrical, I'll make sure that the sound isolating isn't compromised by not cutting these things inside the walls. As for the design, I decided to maximize the space that I had, and include one non-parallel wall looking into the adjoining room. Once the room is built, there will still be a lot of work trying to deflect and absorb sound. Could someone take a look at the drawing and give suggestions about the design. If there is also anyone who has worked with a similar ceiling construction just so I can get a basic idea as to whether the This will not be super high-tech, but I hope that it will at least imitate a well-isolated room, and perhaps give the possibility to record, Hope to hear back soon! Randall

welcome! could you provide the room dimensions and perhaps some photos?

Thanks Glenn! I really appreciate you taking a look. The perimeter of the construction area is: concrete short wall = 228 cm. concrete long wall = 394 cm. diagonal wall (from the left corner of the water heater into the existing wood panel) = 261 cm. interior short wall = 260 cm. From floor to joists is 211 cm. Wish the space could be bigger, but price per square meter in Norway is like Tokyo. The drawing shows that the frames will be set on studs 10 cm wide. I need some sage advice on the joists. The carpenter and I plan to sister 6 of the joists with an additional 2x8 in order to support the extra weight of the drywall. The house was constructed in the 50's and I noticed a slight bow in the joists already. We put a 2 meter straight edge to the joists and noticed on either side there was a 1/2 to 3/4 separation from the straight edge on each side. Are there any negatives in adding addition support such as this? Sonic? Structural? I have a feeling that an addition 2x8 might be overkill. We will tear down the rest of the ceiling today and begin caulking the ceiling. I will wait with the sistering until I hear back. Thanks again , Randall

The joists are 414 cm long, which is 13 ft 4 inches, the outer cement block is 20 cm... will see how much joist is on the inside block later today. Engineer handbook states that this construction handles 10 psf dead/30 psf live.

No bigger than your room will be, you could do this kind of framing and completely decouple the ceiling from the existing house with no more reduction in head room then you would have using rc and clips and get far better isolation from the flanking that you already deal with.

Brien, No extra load on the floor structure and better isolation... PERFECT! Thanks for posting the sketch - it looks very simple and sturdy. After frame construction, the space in-between will be caulk and drywall on the bottom of the floor, insulation, airspace, insulation on top of soundroom, (RC?), 2 layers gypsum with green glue in the middle. Sorry to bother you with a couple of questions here: How much clearing do I need between the two structures - minimum? and would you use the spare cm's to either a) put RC inside the new room or b) create more airspace between the two structures. Thanks again for directing me back to the room-within-a-room option. Randall

The floor is concrete (dry), and I really want to build this as little as possible to keep as much headroom as possible.

You don't need to "build" the floor at all! What you have is fine. Concrete is good flooring, acoustically. If you don't like it aesthetically, then you could put down laminate flooring, which takes up very little space (vertically).

How much clearing do I need between the two structures - minimum?

Enough so that it cannot ever touch, under any circumstances. Maybe a couple of cm. The important part for acoustic isolation is that you have at least 4 inches (10cm) between the two LEAVES, but the distance between the FRAMES only needs to be enough that the are not in contact, and never can be even considering vibration, swaying, sagging, tremors, etc. - Stuart -

Thanks Stuart, 5 cm between the frames will be the goal. The problem before with beefing up the ceiling is now no problem at all. The outer wall of the sound studio is now adding extra support to the ceiling. I've altered the design quite bit using one of Johns sketches a template. continuing with the room-in-a-room design (the inner room dimensions are 6 sq. meters, maximum width of 210cm). I'm using 2x6 boards over the top of the inner room design that will be more than enough to support the weight of the gypsum. The studio build looks like this now. :?: On Baffle box... how do I treat the materials inside the box for maximum isolation and breathing comfort. I can't get OC 703, and I've heard that Rockwool RW3 is a suitable replacement, given that it's sprayed with paint. I've been searching high an low for someone in Norway that stocks RW3 with no luck, but I did come across someone selling their Rockwell acoustic plates 5m thick in the neighborhood. I can shorten the lengths of the boards inside the box to create an airflow ranging between 10cm and 12 cm - the width will be uniformly 25cm. Should I use this material instead inside the box instead of RW3? I read that the Acoustic plates are made to so that they don't release dust into the air when treated with spray paint or spray varnish. My guess is that this is the way to go, but I'd like someone to verify this. THX! Randall As for the box dimensions, I've worked out the dimensions based off of a drawings that I am pretty sure come from Rod, and did a slightly smaller version.

I bought 5 5cm Rockwool Acoustic plates figuring that they would be good to have even if I can't use them for the ventilation. In the mean time, I've been reading posts on how to treat this material so that it will not be released into the air. Seems like there are a lot of choices: fabric, thin plastic. I also heard that a quick and easy way to treat this material by using a breathable "diffusion open" paint. (somehow, seal and breathable seem to be a contradiction to me) Can anyone recommend one or the other for me? Which of these three materials are preferred for air quality and maintaining the damping properties of the insulation - preference towards air quality. I also was able to get the last 3 meter roll of acoustiguard in Norway, it's about 50 cm wide. I am planning to use it around the door and window frames, and place this inside the ventilation boxes for additional mass. I'm also planning to use it on the outside of the ventilation pipes that will go from the boxes into the sound room.

use the thin plastic for ventilation.