4/5mm gap in ply flooring what should I use.

[Aspesim]

Hi Guys

Just a quickie from me today!!

I'm just about to lay 250 hardie-backer board over my ply flooring, however there is a 4/5mm gap between the boards. What should I use between these?
Addy - Silicon - Newpaper!!! lol (I'm only joking with the last) :smilewinkgrin:


As usual thanks guys
Simon.

 

[Andy Tiler]

Silicon