Geo fabric or plastic weed mat under deck?

Hi there,

I am making floating eko decking (close to the ground) which is extending from my afresco and do I need geo fabric & crushed stone under the deck?

If I do, should I put geo fabric or plastic weed mat under the crushed stone?

Eko deck requires a certain air gap underneath as per warranty please check this before installing, mould can be an issue. Weed mat and 20mm bluestone/gravel is enough but the gravel needs to be approx 10cm to stop weeds n pests from nesting under. Personally i have never used weed mat or geo as when it gets wet it holds moisture which adds to the humidity underneath.

Geo fabric is intended to stop dirt washing through it but allows water to seep through to drainage underneath it, its basically a filter. It is not a weed mat to lay on dirt to suppress weeds it will just hold the water if laid on ground.