Decking on a concrete slab

Hi there, in my experience i would avoid laying directly onto the concrete even if it is level and sturdy purely due to drainage issues. With a conventional decking where you have joist work underneath the water/leaves etc have somewhere to go whereas if you lay directly onto concrete you may get water pooling. Especially if you are intending to use timber decking, as it will rot out much quicker

No, don't lay directly on top of a concrete base, as this will trap water and rot the wooden deck boards very quickly. Also have some sort of frame work to allow water to disperse away.

I would advise that you would not lay directly onto the concrete! as a frame would reduce damp and moisture which in the long run would provide your decked area with a longer life.

I would lay a composite sub frame and then lay your decking on that once you have levelled it up no not the cheapest way but neither is replacing your decking after a few years if your doing it in wood that is