ᐅ Concrete slab for garden shed

Hello,

I am currently planning a small garden house for our garden.

It should look roughly like the one in the photo, with a floor area of about 6.00 x 3.00 m (20 x 10 ft) plus a "winter garden".


I intend to build it using timber frame construction with a ventilated facade and vertical cladding on the inside as well.

There is a separate thread about the wall structure:
https://www.hausbau-forum.de/threads/gartenhaus-wandaufbau-reduzieren-wie-welche-wanddicke.29506/

I am now at the stage of planning the foundation.

I have read quite a few proposals for foundations for "garden houses" online, ranging from paving slabs and pier foundations to concrete slabs.

I am leaning towards a concrete slab. The setup that seems most reasonable to me right now is:

Reinforced concrete about 20 cm (8 inches) thick
PE foil
15 cm (6 inches) of crushed stone

Is that sufficient, or do you have to go through the full process like with a standard detached house, including a frost protection footing down to 80 cm (31 inches) deep?

Our soil is Brandenburg forest soil. That means about 10 cm (4 inches) of topsoil, then sand directly underneath.

Does it make a difference for the foundation/concrete slab construction if you plan to have water/sewage/electricity installed in the garden house?

We might want to do that eventually. I would now integrate empty conduits into the slab for this purpose. But do I also have to change the structure of the concrete slab?

Best regards,
Jens