What is the 6mm cork underlayment acoustic value on a concrete slab?

(06:56:27) Visitor 74074667: Hello, I am considering using a 6mm cork underlayment for a glued engineer hardwood application on a concrete slab. The adhesive I am considering to adhere the cork underlay to the concrete slab is Bostik Vapor-Lock which has acoustic characteristics and using the same adhesive to attach the engineered hardwood to the cork underlay. The system would then provide acoustic value to everything except for the hardwood itself. Would this make for a good floor?
(06:56:40) *** Cancork Floor joined the chat ***
(06:56:54) Cancork Floor : Is the slab at, above or below grade?
(06:57:29) Visitor 74074667: The slab is above grade, 8 th floor of a condo highrise.
(06:58:14) Cancork Floor : Then a vapour barrier adhesive isn’t really needed. So long as the adhesive is rated for “concrete” and “cork underlay” you should be fine.
(06:58:42) Cancork Floor : The “double stick” is one of the highest rated (most expensive) installs we have in the flooring industry.
(07:01:01) Visitor 74074667: I was trying to enhance the acoustic rating by using an acoustic adhesive. The condo association wants a floating floor and I am trying to get them to approve a glue down system with better than normal acoustics. 
(07:01:52) Cancork Floor : Without knowing the ‘acoustic rating’ of the adhesive, it is super difficult to figure out how the adhesive will effect the rating for a cork underlay.
(07:02:18) Cancork Floor : In theory the double stick is the best option (from a structural) stand point.
(07:02:54) Cancork Floor : I’m not sure what the Bostik will do to increase the ratings. The 6mm cork underlay is accepted by 90% of condo boards = already approved.
(07:05:09) Visitor 74074667: It appears the adhesive has a IIC rating of 50 for a 6 inch concrete slab, our slab is 8 inches. Would the adhesive affect/reduce the rating for the cork underlay or just add to it?
(07:06:09) Visitor 74074667: The approval you mention, is it floating or glued application?
(07:06:34) Cancork Floor : STC ratings are odd things.
(07:06:51) Cancork Floor : The 6″ concrete = 28- 33 dB all by itself.
(07:07:22) Cancork Floor : So 8″ concrete = 36-38″ dB
(07:09:16) Cancork Floor : The adhesive in theory should add to the ratings of the cork…but the adhesive manufacturer must list cork and concrete as two of the substrates
(07:09:45) Visitor 74074667: Yes they do, both.
(07:10:08) Cancork Floor : Then the only thing you need are the right trowels for both formats of adhesive.
(07:10:48) Cancork Floor : A cork underlay of 6mm would be regardless of installation application. The reason: 6mm of cork is 6mm of cork. That doesn’t change.
(07:11:01) Cancork Floor : Have you received approval for 6mm cork underlay under your hardwood???
(07:12:11) Visitor 74074667: Not as yet, our condo does not have specific criiteria, all they indicate is an acoustic padding.
(07:12:25) Cancork Floor : Then the 6mm will pass.
(07:12:40) Cancork Floor : It is rated as acoustic underlayment
(07:13:05) Visitor 74074667: Can you provide me with the IIC acoustic rating for 6mm cork?
(07:13:20) Cancork Floor : I have Delta IIC ratings for cork + cork underlayment
(07:14:52) Visitor 74074667: What is Delta, I have not come across that term in my research?
(07:15:09) Cancork Floor : How much time do you have today???
(07:16:36) Visitor 74074667: Some, is it that complicated? A competiting underlay Dura-Son MB indicates a FIIC rating of 69
(07:16:54) Cancork Floor : Yes…it should take me 3-4 hours of time to type it out.
(07:17:10) Cancork Floor : FIIC = FIELD IIC testing = almost useless.
(07:17:22) Cancork Floor : Go ahead and Google “Delta IIC ratings”
(07:18:19) Visitor 74074667: It is interesting because some in the industry suggest that is a better indicator than the lab IIC.
(07:18:56) Cancork Floor : Nope…Delta IIC is a PURE number that is ONLY for floor+ underlay
(07:19:19) Cancork Floor : STC/IIC and FIIC ratings REQUIRE the EXACT floor/ceiling assembly as tested = never happens.
(07:19:39) Cancork Floor : If you require more help…please send an email: via contact us
(07:19:52) Visitor 74074667: I am trying to provide a communication to the Condo Board that they may understand and accept.
(07:20:02) Cancork Floor :  Please click the contact us link
(07:22:11) *** Cancork Floor left the chat ***
(07:25:58) *** Visitor 74074667 left the chat ***