How can siphon roof drainage hanging holes not leak?

Want to drain hanging hole watertight method is:

It is necessary to establish effective protection measures for finished products. According to the model of the water stop, the waste formwork is made into a square, and the formwork is fixed on the ground with steel nails to block and protect the upper mouth of the water stop. After the sealing is completed, the periphery of the template is smoothed with cement mortar to form a quadrangular prism. Spray red paint on the surface of the template to indicate the quality of the water stop.