Solid prestressed slabs , usually 600 mm or 1200 mm wide, act compositely with a structural concrete topping, to form a robust composite floor. They act as fully participating formwork that may be propped or unpropped during construction. This method of construction eliminates the need for conventional formwork.

Spans are limited to about 7.5 m (for an imposed loading of 5 kN/mm²) with an overall depth of 300 mm.