In the Event there is a need to buy a terrace or some zone on the roof, and Which Will Be Quite Strong Pressure, A Different Styling System, Which IS Called Ballallist. The Use of Such a Fastener System is Advisable only in Buildings with Reliable Supports. It is system that is offen used in the constructions of elite multi -storey bulldings, The Upper Floors of Which Are Equippe with Terracces.