Casting on an existing slab?

[perr11]

Hi
I am going to cast on an existing slab. It will be a beam that is 4 meters long, 30 cm high, and 10-15 cm wide. How should they be attached together or is it not necessary? There will not be much load on it, it is for a patio.

Grateful for the help!

 

[trojlee]

If you want to be sure, you drill down rebar into the old slab and tie them together with longitudinal rebar along the "beam" you plan to cast... that's how I would have done it..
/
M