Hi, I'm trying to find information on how to build a deck over and uneven concreate surface, I have minimal height from the concreate to the door of the house approx 20cm there for am unable to use bearers and joists plus decking surface, are there any tips out there. I would be greatfull for any information thanks. John. H

There is a product that is a self leveling concrete skim coat.I do believe you are required to pressure wash and use a concrete bond adheiseve.

Forget about a deck, cover it with 1/2 " of sand and lay pavers, unless it it really, really uneven. You might try pieces of random slate with decomposed granite in between, plus sand below, in that case.

20 cm isn't much room. I have built platforms, decks, etc. but there has to be enough height to do it. You just don't seem to have enough room. You may have to come up with something else for your outdoor space. You need to allow some space from your door threshold, to that patio/platform and you just don't have it.

Self leveling cement. Mix waterry and pour away.