Very unsure of where to place the thread, so feel free to move it if it's the wrong place
I have an old root cellar on the farm that probably hasn't been used for anything in a long time, which I plan to fix up to use as a rough storage, so I would like to reduce the humidity as much as possible.
It is (roughly estimated) 2x6 meters, the sides are under the ground, but the roof is at the sides level with the ground, as you understand it goes into a slope. The roof is a vaulted tile roof (quite flat, from the "ridge" to ground level is maybe 2dm) with a lawn above, probably no tar paper or anything underneath.
The ventilation is very simple, an opening about 8 cm beside the door and a 15 cm concrete pipe through the roof at the far end.
The floor is just packed earth.
So, if we start from the top. The roof, scrape off the soil and put on tar paper, then back with the soil? Sedum roof, or whatever it's called, I pretty much already have one, albeit natural

What tar paper is suitable for this, and how do you attach it to 100-year-old tiles in an appropriate way? A gas burner, etc. is available if needed.
Ventilation, a hood is needed at least on the concrete pipe, I can bend one without any problems. Should the hole on the "facade" be opened up more? And then put a ventilation grill over the hole? Anything else?
How do you deal with the walls on the inside? Or is it overkill to tackle them?
The floor then, I have a little wild idea of laying old paving stones over it and then "dressing" it with a pallet, to get a proper air gap under the things you put in. Or is that idiotic? Having to maybe replace the pallet every five years or so is not a problem, it'll be perfect to clean out the mess at the same time then
Other ideas and thoughts? I've never worked with a root cellar before, so I'm gladly taking tips
