Garage/workshop flooring advice

[Stevoid2000]

Hi,

I have a 9x5m shutterboard concrete 'shed' with a sloping and uneven concrete slab floor. I think it used to be used for livestock, so the slope was important!

I'd like to make a level insulated floor over about half of it (6x5m - there's a hardboard wall closing off one side).

My wife and I debated levelling with hardcore/blinding and pouring a new insulated slab across the whole thing, but that's too big a job for now.

So the plan is a suspended timber floor on honeycombed sleeper walls. I'll insulate between the joists and probably use marine ply or similar for the finished floor.

However, there's no DPM and the ground level at the top of the slope is around 50mm higher than the slab floor internally. So when it rains I get a damp patch in this top corner

Here are my questions;
Can I batten to the shuttered wall to support the joist timber?
Where do I put DPM?
Do I need to worry about the damp on the slab?
Presumably I'll have to install some ventilation for the subfloor?

I've been round the internet in circles and have failed to work out the details of this,
Thanks for any help/advice

 

[Tigercubrider]

My mate had an old single 50's garage that at some point was extended (very well) in length.
We converted it into a studio. The floor was typical "garage floor" with bumpy concrete and dips.
We laid a few shovels of concrete over the low points and swung a level between peaks, then filled the gaps left. It ended up reasonably level.
We then used bitumen paint over the whole floor and up the walls to about 18"
Once the internal walls were finished, we laid a polythene DPM and then used rockwool slabs under chipboard flooring that was glued together.
20 years later it still seems bone dry . The polythene ran up behind the skirting

 

[Stevoid2000]

Thanks Tigercubrider. That sounds pretty straightforward, and would probably work well, except that the level drops over 30cm across the half (5-6m length) we're thinking of doing! I was going to shovel a ton of hardcore then thought a suspended floor might be easier.

I hadn't thought of bitumen paint to keep the damp from coming through the edge of the slab though...