New Wave Studios wrote:Thanks Rod,
Yea it does sound like this might be difficult to sort out.
What I dont understand tho is about the floor..
Surely if its already concrete and we run some timber over it resting on the neophene (??) pads and pack it down with Rockwool/sand covered by sheets of ply/plasterboard with thickunderlay and carpet surely thats going to help?
Not necessarily, in fact it could actually hurt.
What you're describing is a pretty good deal for impact noise - so great for a bowling alley - a dance floor - etc., but not for the LF that comes with bands.
This from Mason Industries - one of the leaders in the sound isolation product industries:
“It is often necessary to provide a wooden floating floor rather than the heavier concrete construction with wood topping. Cost or weight restrictions may be the factor. In older buildings it is often necessary to improve on existing floors with a lightweight impact noise resistant construction. A resiliently supported wooden floor will reduce the rumbling noise of a bowling ball, the click, click of a woman’s heels and that portion of a typical noise generated by a piano that travels down the piano legs and into the structure. It will offer only minor reduction of airborne sound, as there is insufficient mass in the surface. In some applications on stages or in rehearsal rooms the primary purpose is relief and comfort for the dancers. Landing on concrete or hard mounted wood surfaces is very damaging to a dancer’s feet and legs.”
Now - to clarify - when I say it could hurt.
An assembly can actually magnify sounds, that are in the process of passing through a system, at or around their center frequency.
Thus building the wrong system can be worse than building nothing at all.
I might consider doing a sand filled - but then again we are back to the weight issue.
One other thing - once you have plans it is critical (I cannot stress this enough) that you have this approved by a structural engineer before constructing - in fact - if your building official has any brains at all - he will insist on it.
When everything is said and done - even without a concrete or sand filled deck - you are adding a lot of weight to the existing deck here - and should not leave anything to chance.
One thing about deck failures - they are catastrophic in nature - there will be no indication of anything wrong - and then in the next second it's all over.
You would be absolutely amazed at the number of people who have told me (on this and opther forums) that there was no problem - they knew for a fact that the deck could support their loads - that have come back and thanked me for insisting on this - because their engineer told them "no way - no shape - no manner".
I hear you about the ceiling, what about a half ceiling so at least we have a little area above 8 x 16 or something??
I suppose you could talk to your official - but the what the codes proscribe don't leave a lot of room for conversation.
Rod
Ignore the man behind the curtain........