Hi all I'm building a garden room/office inside a single skin building with concrete floor. As well as appropriate work on the walls (battens + breather membrane), I have put down DPM + suspended floor joists. I've insulated with PIR between the joists (100mm Kingspan), and foamed any gaps—but now I'm stuck. I've got 18mm OSB3 T&G to put down. After I tape joints on insulation with alu tape, do I still need a VCL? Or does OSB3 act as VCL? How do I glue the OSB3 to the VCL? (I've got D4 glue) How do I screw the OSB3 to the joists without compromising the VCL? (I've got floortite screws) Thanks for any/all help!