Dry up any water pooled over the concrete before continuing.
How to concrete over old concrete.
Pouring concrete over old concrete instead of directly over a new gravel foundation limits your ability to maximize the slab s lifespan.
Make sure all of the old concrete has a layer of slurry on top of it before you move on.
So if you pour new concrete over the old surface without preparing the one.
This old concrete patio was a perfect candidate for pouring new concrete right.
Get the old concrete slab completely wet making sure any cleaning chemicals you used get rinsed off in the process.
The surface was badly worn and pitted but the slab was sound and there was ample height to pour a new slab right over the old one.
It was originally poured in multiple sections so it had some seams that looked like cracks.
The form shall extend above existing concrete surface based on the designated thickness of the new concrete.
Brush the slurry over the damp concrete to form an even layer.
Make sure that the height of the formwork is even.
The old concrete was over 20 years old.
When i say bond the concrete you are lying on top off needs to be a rough finish like scabbled.
Before you add your new concrete take a large brush and dip it into the bonding slurry.
Spread the new concrete over the surface filling the entire area within the form you created.
Concrete is porous so it can absorb liquid.
You could drill holes into the existing concrete surface and insert steel pins and then the mesh on top.
Smooth the surface using a two by four or float then add texture as desired using tools or a broom.
If you are laying pouring concrete over existing concrete there needs to be a bond.
When pouring new mix over old concrete make the mixture stiffer than usual by adding less water.
As mentioned earlier concrete in itself doesn t have any binding properties to take the load of an additional new layer.
Keep spraying it until the moisture runs off the sides instead of being absorbed.
Layering new concrete over old isn t a durable option only when the materials used are of poor quality or if one skips the binding procedure.
Install the form usually wood form around the perimeter of old concrete surface.
Pouring over old concrete need similar basic formworks that employed with fresh pours.
Brush a thin layer of the slurry mixture onto the old concrete.
The condition of the existing slab is the primary factor that determines how long the new concrete will last.