How to concrete a small area with fall to the fence?

[PatDIY_Dad]

Hi

I need to concrete just a small area that will be next to existing concrete 

the area is about 1m wide x 600mm length x 100mm deep

So I have a general idea on what to do but need someone to say yeh thats right or you forget x y z

So  After I have removed about 120mm deep of soil:

• Put some crushrock down leaving about 100mm for concrete
• Drill some holes into the adjacent existing concrete with those steel bars to stop the new concrete from sagging or lifting ( how many mm apart should I put those in?
• Do some formwork ( 100mm high) ( wont be much as its going in between a timber fence and existing concrete
• Put string line in the direction of where I want the fall to be for water run off. Then get a leveling and rest it against the string to check the fall ( is that how you do that? )
• lay concrete and smooth off level with existing concrete and level with string line
• Remove string line and smooth off
• After concrete is dry, remove form work and so some saw cuts 
•  

[MitchellMc]

If you were to create two separate slabs without mechanically connecting them, you'd need an expansion joint. This expansion joint must be directly below one of those flexible silicone joints in the tiles. Either the two slabs float next to each other with an expansion joint without being physically connected, or you add reobar to the existing slab prior to pouring the new slab to mechanically connect them. You wouldn't mechanically connect them and also have an expansion joint, as that really defeats the purpose.

Mitchell