What size Plywood Overlay?

[theandroids]

Hi, all I was thinking of putting down solid oak Parquet flooring. I currently have particle board subfloor. I know I need to put overlay the floor first. My question is could I use 3.5mm - 5.5mm Plywood sheets screwed down to the particular board. or do I have to use 6mm. Also what type would I need?
Alternatively, whould I be able to use 6mm hardiebacker instead?

 

[Deleted member 174758]

TBH Hardiebacker might be a better choice than 1/8in plywood as it's nearer to the concrete/screed type material that you so often find original parquet flooring installed on and is far less absorbent than plywood