Masterboard in suspended timber floor - sealing gaps

[Roz]

Hello, 

 

We are building a workshop alongside our barn conversion. It's a SIPs workshop but the floor is timber frame, sitting up on jackpad plinth foundations. We've been told to put master board on battens on the inside of each section of the floor, then rock wool insulation on top of that, then chipboard deck. We've been cutting them to size but have some gaps around edges of the masterboard. Would you advise to seal around the edges with expanding foam, or silicone, or some sort of tape? Or just leave them with air gaps?

Thanks in advance!

Roz