# Forum Home Renovation Concreting  Slab on dirt & old slab

## Moneypitt2

Hi guys, Im wanting to pour a decking slab over an existing at grade slab and dirt / grass. The new slab would be 200mm to match an existing step.   https://ibb.co/cD9C2xr Is the best image.  
Any thoughts about how to best do it? 
I have a ton of brick and old cement rubble I was hoping to use as fill.  
Should I pour two slabs with an expansion joint at the line of the existing at grade slab? 
Thanks

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