Before pouring a new layer, it is necessary to remove concrete milk from the surface.
The “cold seam” option is characterized by an excerpt for a longer time between the shutter of individual layers. Ideally, they try to wait for the complete hardening of the already flooded part. This is due to the fact that if you can not withstand the time of hardening not only the upper crust, but the whole concrete composition, the crust may crack. But at the same time, under a new layer of concrete, cracks will not be noticeable.