"Is zakat due on money saved for building, which represents the sale value of my current apartment, even though it is not surplus to my basic needs? "

Zakat is obligatory on wealth if it reaches a nisab and a lunar year passes over it, even if the owner needs it to build a house or buy a car. This is the opinion of the majority of scholars, with the exception of some Hanafis who exclude wealth prepared for basic needs. The predominant view is the obligation of zakat on wealth if its conditions are met, which is a quarter of a tenth, a small part that increases the blessing of the wealth.