A far simpler construction method would be to mount isolated ceiling joists resting on your side walls. So instead of trying to hang something from the concrete ceiling just build a decoupled room inside a room inside the concrete bunker. What are the room dimensions?

 

A far simpler construction method would be to mount isolated ceiling joists resting on your side walls. So instead of trying to hang something from the concrete ceiling just build a decoupled room inside a room inside the concrete bunker.

Did this in my last build thanks to your suggestion, can vouch for the effectiveness of this approach. Ceiling height might be a consideration between this and suspension but the freestanding room is great for not transferring sound.

 

Thanks or the response Jeff.

The room is 27 ½ x 20 x 11

 

Just did a quick look up on my mobile device and 2x8 no 1 SPF (spruce pine fir) spaced 16 inches on center can handle the weight of ceiling construction for a span of 19 1/2 ft. I Would want to double check if you think you want to go that route.

 

no 1 SPF (spruce pine fir) spaced 16 inches on center can handle the weight of ceiling construction for a span of 19 1/2 ft

Sorry Jeff, I don't understand what you're saying. Your recommendation won't work?

 

No it should work fine, Frame your walls short and rest ceiling joists on top, insulate between the joists and install double layers of drywall with green glue. Now finding lumber that long may be a issue may need to use engineered joists.

 

Frame your walls short and rest ceiling joists on top, insulate between the joists and install double layers of drywall with green glue. May need to use engineered joists.

That's a great idea. I noticed that Sor did the same thing.

Several of us have bunkers and the ones I’ve seen just use concrete anchors for joining framing to the ceiling slab with clips. One or two just used powder activated nails and nailed 2x4s to the ceiling. If someone was tap dancing above on that concrete with the hard shoes I’m sure the tapping would translate, but in general I’ve been really satisfied with the way concrete stops sound.

That's good to know. The issue is, that the covered porch my theater is under will be a fairly hi traffic area in the summer months. There's a 23' lift and slide door that connects the great room to the outdoor living space. So there is a possibility of high heals walking on the ground. This would likely only happen if we were entertaining and it may only be a couple times a year. Unfortunately, that's when the theater will be on full display.

Do you have a "excessive" subwoofers, coffered ceiling, or anything heavy added to the ceiling?

Nothing excessive. The theatre design will be staggered so I will be able to add extra insulation in the front 3 sections because the ceiling cavity will be larger. That should really help. (see attached)

For the door into the room, how much headroom do you have from the top of the door to the unfinished ceiling?

Great observation. My basement is will be 10'. 9-6" with the ductwork buried and a flat ceiling. If I went with an 8' door I will still have a lot of room walking inside the theater.

Attached:

1 - Side building elevation. (completely ignore the floor and ceiling my architect added) It will be 11-2" deep with no floor/ceiling.
2 - Cover porch - my theater lobby is under the bbq, and the theater is under the porch.
3 - Theater Design - Staggered/Stepped not sure exactly what it's called but that's the design.
4 - Overhead layout - This has changed slightly but you get the idea of the walls and layout.

 

Several of us have bunkers and the ones I’ve seen just use concrete anchors for joining framing to the ceiling slab with clips. One or two just used powder activated nails and nailed 2x4s to the ceiling. If someone was tap dancing above on that concrete with the hard shoes I’m sure the tapping would translate, but in general I’ve been really satisfied with the way concrete stops sound.

The screen wall of my theater is 12” of concrete out to a ground level basement (theater is only buried 4ft in that area, and it’s deeper than the rest of the basement). We have had lawnmowers going out in the back yard and you would never know in the theater.

 

Do you have a "excessive" subwoofers, coffered ceiling, or anything heavy added to the ceiling?

 

I’ll add one more clarification question. For the door into the room, how much headroom do you have from the top of the door to the unfinished ceiling? I only ask because a lot of concrete bunkers end up not having a lot of leeway there.


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That's a great idea. I noticed that Sor did the same thing.

Just to clarify - I framed short and then laid 20ft 2x4s vertically to span the space. I used joist/rafter ties to attach them to the wall framing, and I also anchored each 2x4 to the ceiling with clips and 2 ton concrete anchors on the thirds (about every 6 ft).

Even though I had 12ft 4in ceilings, as Chirpie alludes to I was concerned about losing headroom, especially with a soffit in the plan. Wheee you enter the room it is 4ft to the floor and 8 ft to the ceiling, cutting out 12” or so for a joist would leave 7’ headroom, not enough for a soffit. This way I lost about 4”.

This is going to be a phenomenal room, judging by the plans.

 

Thanks Sor. Your room is phenomenal as well hope mine turns out ½ as nice. I'm with you on the height, and extra height that can be saved would be fantastic.

Couple questions...

1) I looked at your build again and I the anchored 2x4 seems to be a little more random. Not in the same location on each 2x4 but it may be the image I was looking at. Did you fasten every 2x4 about every 6ft?

2) No vapour barrier on the walls? Behind your ceiling speakers? Not sure what your climate is like.

3) Did you spray foam your entire riser?

 

Great looking theater plans. Love the stepped walls. Can't wait to see this one come to life. Have you actually started construction yet?

 

2x4's can't span 20' unless you tie them into the ceiling like SOR, but then you lose a degree of isolation, especially for that footfall noise. In post #4, BIG mentioned 2x8's for a 19-1/2 foot span.

Mike

 

this is the resource I use for span limits (screen grab), your lumber species may vary. The logo is blocking where I selected ceiling joists, with the minimum live load above and spacing of joists 16 inches on center.

 

this is the resource I use for span limits (screen grab), your lumber species may vary. The logo is blocking where I selected ceiling joists, with the minimum live load above and spacing of joists 16 inches on center.

Thanks for this

notes on your design, you don't use "staggered studs" on walls built inside concrete foundation walls, only walls shared with other occupied areas. The stepped walls and ceiling is a nice design touch and there have been some theaters built here using that concept. From my collection of photos I wanted to share the picture of the stepped ceiling framing built inside the sound isolated drywall shell, basically you build a second false ceiling. From Erskine Group theater design and Steve Kujala theater builder. If you know what to look for you can see they use that avaiable cavity for ductwork and lighting. Do you have a builder who is going to tackle this design for you?

Thanks for the notes and the shared photos. I have been scouring the forum for bunker builds and also review the stepped ceiling. Sound proof the room, build the steps. My plan is to hide the HVAC in the steps but I have a couple roadblock's that I'm working on with my HVAC engineer. As for a builder, my original plan was to use a dedicated theater builder but guys like Steve are in the USA and I'm in CAN and with covid, construction won't happen. I will likely be working with my home builder but my intention is to have exact plan details for him to construct and I can manage the project. I would love to build it on my own but it's far too important for me to mess something up. I just don't have the skill.

Steve cuts those curved wall framing top and bottom plates on a CNC machine in his shop. I did and old school version for one project where I cut them using a long swing arm and a jig saw. In your construction planning you need to plan how to attach all that additional framing,

I like the curved look and have played with a bunch of different renderings with Francisco the 3D designer but the curved didn't work out the way I wanted to so I'm sticking with straight steps.

Thanks again Big.

 

notes on your design, you don't use "staggered studs" on walls built inside concrete foundation walls, only walls shared with other occupied areas. The stepped walls and ceiling is a nice design touch and there have been some theaters built here using that concept. From my collection of photos I wanted to share the picture of the stepped ceiling framing built inside the sound isolated drywall shell, basically you build a second false ceiling. From Erskine Group theater design and Steve Kujala theater builder. If you know what to look for you can see they use that avaiable cavity for ductwork and lighting. Do you have a builder who is going to tackle this design for you?

 

notes on your design, you don't use "staggered studs" on walls built inside concrete foundation walls, only walls shared with other occupied areas. The stepped walls and ceiling is a nice design touch and there have been some theaters built here using that concept. From my collection of photos I wanted to share the picture of the stepped ceiling framing built inside the sound isolated drywall shell, basically you build a second false ceiling. From Erskine Group theater design and Steve Kujala theater builder. If you know what to look for you can see they use that avaiable cavity for ductwork and lighting. Do you have a builder who is going to tackle this design for you?

Hi Jeff,

I'm still a ways away from drywall but do you have any more information on this build? I would like to find some construction photos. My fist thought is it's a bit overkill on the 2x4's but I'm guessing the fabric panel track needs to be fastened every 16". This really does help though.

 

Steve cuts those curved wall framing top and bottom plates on a CNC machine in his shop. I did and old school version for one project where I cut them using a long swing arm and a jig saw. In your construction planning you need to plan how to attach all that additional framing,

 

You are definitely going to have an amazing space to work with and seem to be going about it the right way as far as researching the proper methods. Nyal is awesome and you are in good hands there. I would tend to lean towards Big's suggestions here and not mess with doing the hanging brackets instead building the joists on top of isolated walls. And there's no way I would use factory made damped drywall - it is just way too expensive (and only 1/2" thick???) - when two layers of heavy 5/8" drywall with Green Glue in between is superior and cheaper....

 

Thanks P3Bham, I appreciate the kind words.

I think HVAC will have a significant part in the decision. Joists on isolated walls does seam a lot simpler for me. I have double drywall & GG in my current theater but I will go with Nyal's recommendation for this one.

 

Thanks for the clarification Nyal. I misunderstood what you were going after and should've known you had a reason...

 

back to the theme of this thread, you should read: The Kobayashi Maru Theater

 

That’s a beauty.


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I linked the part where he made his own rubber bushing attachments for the ceiling.

 

Talked to Nyal today. The spray foam causes some issues so does the attached framing for the stepped ceiling. It's definitely more in line with what I would feel comfortable with my builder doing as well. I wish there was something other than 2x8 that can span the width of my room.

 

I don't believe that ceiling had treatments, not all theaters do, a stepped ceiling is in of itself somewhat of a treatment. You could ask Dennis Erskine the designer. He has a facebook page for the Erskine Group and that picture is there.

I don't see anything wrong with your idea of doing a stepped fabric ceiling.

 

Thanks Jeff.