Yes.

Glue down on slab in Florida...fraught with danger!!!!! If the engineered has the ability to float...then the "appropriate" form of install in Florida = floating. Time and again we (flooring professionals) hear about glue down hardwood (glue down anything it seems) in Florida being ruined inside of 3 years.

Extreme diligence must be maintained by VERY expensive installers (don't go cheap with Floridian flooring installers...it always costs so much more if you do) who use very expensive adhesives in very expensive amounts to get the floor to "work" (not ruined inside of 5 years). Even when everything is done "right" (correct moisture measurements done 3 times prior to and during installation, correct adhesive, correct trowel, correct spread rate, correct amount of gallons per 100/sf,etc) a moisture barrier (glue/slab sealant) can be overwhelmed when moisture hits "X" level. In Florida you have a very good chance that sometime in the future your slab will hit "X" level. At that point, the floor is ruined. Even when everthing is done "right".

A floating install = plastic sheeting (6mil or 10mil) over the slab (or a vapour barrier+underpad). This form of moisture barrier will out perform every glue/slab sealant on the market. The install is cheaper (much cheaper...you would be suprised how much cheaper) and the floor has a much better chance of "surviving" past its 5th birthday.

Sad but true. Please think about floating. Floridian water tables are the reason why floating hardwood exists.

Yes. If you send me your email address I can send you the NWFA official install guide.

I'm thinking about installing engineered hardwood on my second level in GA. Do I need an underlayment if I'm glueing the wood down?