I am really stumped about an issue and have been researching and making calls for three full days. I am installing a pre finished 6″ wide solid wood plank floor on top of a plywood subfloor from a company that assured me I could use a water based glue. The installer now tells me that he does not recommend this type of glue for this application since the bond will not be strong enough and the water content will warp the floor. They are nailing this floor also but the underside of this floor has a pre finish on it. This finish is not a water based product but is u/v cured. I have chemical sensitivities and am trying to avoid chemicals of concern. I’m afraid I have to pick my poison but don’t know what to do. I looked at the healthy bond adhesive that is mentioned on your site. it is not made any more but was told that it was made by dri tac and the procduct is their 7700 adhesive. It is an ms polymer. When I spoke to someone at that company they seemed to think this was not a good choice for this application either. The installer wants to use titebond green choice premium construction adhesive #4222. It is an mdi based product. I was told that once cured it is inert but I am concerned. Can MDi based polyurethane adhesives emit voc’s and chemicals of concern over time? Do you think this is a safe choice? They are installing on Monday and I need to locate the product I decide on.