Client Riser Construction

Hi all, What is the proper way to construct client seating platforms so they won't vibrate like drum heads as in Rod's reply in "The Infamous Floating Floor" thread? Is wood construction even useable, or is concrete neccessary? I would think that with 2x8 framing, multiple layers of 3/4" plywood, and filling the structure with insulation the resonant frequency could be low enough so as to not matter, but....... The plan is for a bi-level platform: 1 step up to the client credenza, then one more step up to the couch area. The entire footprint of the platform would be about 18'w x 10'd. Thanks in advance!

JoeMilner wrote:

Hi all, What is the proper way to construct client seating platforms so they won't vibrate like drum heads as in Rod's reply in "The Infamous Floating Floor" thread? Is wood construction even useable, or is concrete neccessary? I would think that with 2x8 framing, multiple layers of 3/4" plywood, and filling the structure with insulation the resonant frequency could be low enough so as to not matter, but....... The plan is for a bi-level platform: 1 step up to the client credenza, then one more step up to the couch area. The entire footprint of the platform would be about 18'w x 10'd. Thanks in advance!

Assuming that you are constructiing above a slab on grade - fill it with sand when you finish....... BTW - understand - the big issue is not noise in the room you're in (as far as problems go) - it's what happens to isolation if using this as part of an isolating assembly. You stated "I would think" , etc. etc........ and you are correct - it can be done - I state that in my book - HOWEVER - I also point out that you are not going to do it with a simple frame and a couple of layers of plywood, etc. Picture the mass of concrete it takes to get down around a 10Hz center frequency - and translate that (roughly) into framed mass. Can you do it - SURE,,,,,, can you do it cheaply and more effectively than concrete - doubful........ could you do it on an elevated deck that it was structurally impossible to put the concrete on due to loading - NEVER...... That's just the way it is...... Sincerely, Rod

Hi Rod, Thanks for the quick reply and very helpful info :) Fortunately, we're only in the VERY early planning phase of this remodel of our existing film mixing stage, so there's plenty of time to make this change! best,

Hi Rod, Bought your book, what a treasure trove of info (I know, I'm preaching to the choir at this point) :) I read the section about filling raised platforms with sand, and hope it would be an alternative to concrete for me. The mixing stage is constructed on a 4" slab-on-grade. Isolation is not an concern, I just don't want the riser to be audibly vibrating. I think having a riser filled with sand would allow me to modify things down the road without needing a jackhammer, which is reassuring. The console is at floor level, and as I mentioned in my 1st post, the riser would have 1 step up to the credenza and 2 steps up to the rear seating area. So, if sand will be acceptable for my purpose, is there a framing schedule to follow for this type of construction? ie; joist spacing, deck thickness, lining for the sand etc.? And, could I use sand for the ADA ramp (to the 1st level) as well? Thanks in advance, and thank you again for writing your book! best,

Anyone? Thanks in advance :)

Any info at all? Thanks in advance! :)

If it's resonance/vibration you're trying to squelch, then perhaps Green Glue can be a part of the engineered design... :roll: --Keith :mrgreen:

JoeMilner wrote:

Hi Rod, Bought your book, what a treasure trove of info (I know, I'm preaching to the choir at this point) :) I read the section about filling raised platforms with sand, and hope it would be an alternative to concrete for me. The mixing stage is constructed on a 4" slab-on-grade. Isolation is not an concern, I just don't want the riser to be audibly vibrating. I think having a riser filled with sand would allow me to modify things down the road without needing a jackhammer, which is reassuring. The console is at floor level, and as I mentioned in my 1st post, the riser would have 1 step up to the credenza and 2 steps up to the rear seating area. So, if sand will be acceptable for my purpose, is there a framing schedule to follow for this type of construction? ie; joist spacing, deck thickness, lining for the sand etc.? And, could I use sand for the ADA ramp (to the 1st level) as well? Thanks in advance, and thank you again for writing your book! best,

Joe, 1st- thanks for your kind words........ 2nd - frame it anyway you want - use any sheathing you want - I don't advocate the use of a liner - fill it with sand to just barely over the top of the joist - and then install your deck sheathing. It's really that simple......... Sincerely, Rod

OK, another question, since Master Gervaisan seems to be frequenting this thread.... :wink: What if, instead of "sealing" the frame and filling it with sand, you left the front end of the frame open, so that air could easily get under the floor between the joists, and filled the space between the joists with insulation? Would you get any sort of bass trapping benefit from it, since sound could easily go under the floor and be absorbed by the insulation? The front, visible "step" leading up to the raised client area could be covered with a false, acoustically transparent front, like a speaker grille, to allow sound under the "floor" to be absorbed by the insulation underneath. Would this be of any acoustic benefit at all? If it's not sealed, won't that change the way it resonates? Help me understand.... JWL PS - Agreed, your book rocks, THANK YOU for writing it. I'm ashamed it took me over a year to buy it.... :oops:

Thanks so much, Rod & Keith, for the info:) Sometimes I have trouble believing "it's just that simple". It's gotta be complicated, right????? So this sounds dumb, but is there a "special sand" I need to use? Somehow I doubt my local supplier would have "studio-grade" sand. haha Do I need to worry about moisture? And jwl, the idea of an "open" platform sounds very intriguing. Would it work, Rod?

Bump..... I'm curious as to the viability of the client riser/bass trap idea a couple posts up.... Anyone? Gervaisan? LOL