A properly casted roof top is one of the most important structures that needs careful consideration and work. When casting, concrete should be deposited continuously as near as possible to its final portion without objectionable segregation.

In slab construction, placing should be started along the perimeter at one end of the work with each batch discharged against previously placed concrete. The concrete should not be dumped in separate piles and then loaded and worked together; nor should the concrete be deposited in large piles and moved horizontally into final position.

Such practices result in segregation because mortar tends to flow ahead of the coarser material.

In general, concrete should be placed in walls, thick slabs or foundations in horizontal layers of uniform thickness - each layer should be thoroughly consolidated before the next is placed. Timely placement and adequate consolidation will prevent flow lines and cold joints that result from placing freshly mixed concrete on concrete past intial set.

These areas should be waterproofed not only to protect the reinforcing steel but also the concrete as well. Radcon Formula # 7 , Krystol Internal Membrane (KIM) or Krystol T1/T2 will protect these areas. There is also the Krystol Joint Repair System, should there be a construction/cold joint.