I have a kitchen and bath showroom in the Midwest. We added flooring about 3 years ago. Our focus is on the contractor market so we do not offer installation. This has worked well for 25 years with cabinets but has been a challenge with flooring. Our first larger project was in July of 2017, approx. 6500 SF of Novalis Lyndon Plank glue down with DriTac 5900 Megabond adhesive. This was in 8 apartment, 4 were main floor over concrete and 4 upstairs units were glued directly to the ¾ Advantech. In August of 2019 The apartment owner called and said there were large gaps at the ends of the flooring. Some of the gaps were more than 1/8” and many of the planks measured 35 7/8”. I had reps from Novalis and DriTac out and neither accept any responsibility. Novalis says their warranty only covers mfg. defects for 1 year and they wont cover performance with someone else’s glue. The reason I used DriTac back then (now I only use what the flooring mfg. recommends),was that my sales rep said that their warranty covered flooring and install. Learning the hard way that that doesn’t help if there is not a glue failure! Both refer to the fact that there should have been underlayment over Advantech but the problem is the same on the concrete. Any advice or comments would be appreciated.