ᐅ Floor for a Self-Built Garden Shed with Insulation

Hello everyone,

I built a timber frame garden shed on a concrete slab. The shed will be insulated within the wall cavities (the facade has a ventilated cavity). However, I’m currently stuck when it comes to the floor. At the moment, I have just a bare concrete slab, and I’m considering the following setup: timber battens with rigid foam insulation panels in between (installed as precisely as possible), and finished off with floorboards. Do I also need a vapor barrier for the floor, similar to what is required for the walls? And if so, should I lay it directly on the concrete slab or underneath the floorboards?

Thanks and best regards,

Robin