Sound Isolation in Condo - AIIC of 60 Needed
We have a condo project with a simple and straightforward challenge. First off - I've already recommended a great acoustician to the Client, as we always do in situations like this. So no need to advise me to hire an expert :-), one has already been recommended.
In the meantime I did a little research on it myself. The requirement for this building is an AIIC of 60 between floors. To achieve this, a 3" or so floor build-up is required per condo specs, and the Client does not want to lose 3" when the ceiling height is already around 8'. So we'd like to come up with a floor assembly that can hit 60 AIIC, uses real wood and doesn't eat up 3".
The floor is an 8" concrete slab which measures 32 IIC. Having looked at numerous underlayments, they all top out around 25 DB (using Delta IIC and not the bogus IIC ratings most of them provide). So 32 + 25 = 57. The Client has had a few different underlayments tested, and the highest IIC they've been able to achieve is 59, one short!
So the question is, are there any underlayments out there with a Delta IIC of 30 or so, that can be used with hardwood floors, and help us to get past 60? I've looked but have not been able to find one.
Thank you in advance for any assistance.