Top of

The bottom of the pit is filled in the form of a puff "pie", alternating fine -fractional crushed stone and sand 10 cm in layers. Each layer is watered with water and tamped with a vibration plate. To give strength on top of a compacted surface, a concrete solution is poured with a five -centimeter layer, leveling the bottom of the pit. On top of concrete, waterproofing by roofing ground is made.