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The Cover & Cut method (or “ top-down” method) is a variation of the cut & cover method.

The phases of this construction methods are as follows:

	the vertical retaining panels (piles, diaphragm walls, etc.) along the perimeter of the excavation to follow are constructed from the surface,
	an excavation is initially carried out up to the level of the roof slab of the structure. Depending on the excavation depth, a light retaining of the slopes may be needed,
	the roof slab on the excavation bottom is concreted. The slab is connected with the perimeter retaining and it is supported on it,
	backfilling works are carried out over the slab and the surface of the soil is reinstated,
	the excavation works for the station or the tunnel commence underneath the roof slab by means of the ramp which has been left at a certain point. The excavation is executed in phases, while the required retaining elements (e.g. anchors, struts) are installed gradually.
	upon completion of the excavation of the entire trench, works related to the construction of permanent bearing structure elements commence. These elements usually consist in the raft (foundation slab) and the lateral walls, while in case of a station it is also the construction of intermediate floor slabs. In case diaphragm walls are used as a lateral retaining means, other permanent walls are not constructed, since the same diaphragm wall act as a final perimeter structure.

The advantages of this method consist in the reduced time of extended worksite occupations and the rate of reinstatement and release of the area for use (vehicular circulation, squares etc) for use and finally the mitigation of disturbance as to the functions of the city. Its disadvantages are the increased cost and the more complicated construction procedure.

As to the Athens Metro, this method was used only for SYNTAGMA Station (of Line 2) due to the particularity of the area. The design provided for the construction of steel piles along the perimeter of the station and the concreting of the roof slab in Amalias Avenue in two phases, in terms of the road pavement width and then the construction of the station in phases as described above. During the construction of the bearing structure of the station, the external walls were constructed from down to top. In their interior, the steel piles were integrated, thus being part of the permanent walls of the Station.

It is pointed out that the cover and cut method by means of diaphragm walls is foreseen to be the construction method for the Thessaloniki Metro Stations.