How do I pour new concrete over old concrete?
Depends if your pouring a veneer or a new slab. not specific enough so I’ll just give you a general answer, when pour new over old. The old surface must be cleaned and scarified. If it were a slab you would treat the old concrete as the foundation and simply pour over it. If it were grade beams and structural work , your going to have to remove all old concrete and work the soil per specification on the structural sheet per the structural engineer
So my advice is:-
- Identify the old concrete see if there is structural cracks or settlement.(sacking or depression of concrete surface)
- Repair it first.
- To pour concrete over the old slab needs an expert like structural contractor who know how to do it. As it requires reinforcement or rebar with proper spacers at a minimum of every 600 mm both ways (hope you understand the meaning).
The idea is the new concrete slab you are pour it over must be rienforced (R.C) not a ‘mass concrete’ to be effective.
It’s best to get a specialist to do the job.