Hello, So i have Abit of a ongoing problem with creaky chipboard floors in a newly built 2016 house . I have multiple areas where the floor creaks and groans which the builder tried to screw down numerous time. I don't believe that the issue is all to do with loose screws in the actual chipboard as the creaking comes from the partition wall base plate in one area, a top plate on a partition wall (when walking above) in snother and in a hall where you step off a set of stairs. I've explained to the builder I believe its flex in the joists causing the problem (which no comment was offered from them) would cross bracing the joists minimize movement and help reduce the problem. I'm no expert and and trying to offer any ideas to the builders to help move this along and hopefully not go down the nhbc route. Cheers!