Steel shed base 2 stage question

[wiciu]

Hi,
Im doing 3m x 5m steel shed base in 2 stages
Stage 1 was strip foundation.
Shed was put, now I want to pour floor inside.
I imagined I will lay out DPM and tape up against the walls and pour concrete over.
The problem I have is metal shed profile. Its hollow inside and 45mm high which I about the hight over foundation I wanted to pour.
I cannot figure out how to lay out plastic.

I don't want to leave it hollow so I can stand eg shelf there and I wanted to seal to the wall to keep moisture away so I was thinking to put DPM inside and pour 1cm over profile height like this

Would you have any better ideas?
Thanks

 

[robinbanks]

What does the outside look like? Do the panels come off the frame?

 

[wiciu]

Steel panels sit on top of strip foundation so currently, without the the floor, you can see some wet spots inside when it rains