i'm about to do an install of 5/8" engineered hardwood (urban floor villa caprisi collection) over, i believe is concrete slab in my 4th story condo unit. it seems like every installer i've talk to all want to put a 1/2" cork underlayment for acoustical barrier glued to the subfloor and glue the wood over the cork. my concern is height and transition after the install. a neighbor of mine just had their floors redone and gained about 2 inches in height. i've done a little research and found that floormuffler or whispermat hw is thinner and has a higher IIC rating at 2-3mm thickness. does anyone have any experience with either of these products?

my other question is whether to float the engineered floor or do a glue down installation?

thanks.

Half inch cork? I've worked with quite a bit of 1/4 inch cork underlayment in the same scenario...highrise. Large majority are glued engineered installations rather than floated.

What needs to be used likely has to be approved by the condo association? What do they say?

quote from HOA rules: "new flooring system shall provide a minimum tested Field Impact Insulation Class (FIIC) rating of 60 for a minimum NAVLAP certified laboratory tested IIC rating of 65."

besides that, they have a "recommended" 7 step method that add about 1" in underlayment height.

I like cork.

Look into using cork underlayment. I know a lot of customers who have used this to meet their HOA demands. You can go to the below link to download the spec sheets that you can show the HOA board. Good Luck

http://apccork.com/cork_underlayment.php

John
APC Cork

thanks everyone, for your input. john the specifications pdf was really informative. i'm going with the 12mm cork underlayment.

Glad that helped.

John
APC Cork