First of all you would require making a decision on your budget and the budget would depend on the amount of your funds. The financial plan would also depend on the number of members that will stay in the house and the space required per member. Most homes or flats nowadays are sold on the basis of Built Up Area, that is the area between the walls and including the width of the inner and outer walls. Most projects today talk in terms of Super Built Up Area, which includes common spaces like stairwell, passages, and corridors. Your budget of home is depends upon all these issues.