House Design Four Floor A house design with a four floor plan is called a g+3 building. Houses with this design are also called multy story building or simply “apartment”. Usually, when you visit these residences, they are always furnished and have several bedrooms.There are four sets of floors that are commonly seen in these House Design Four Floor residences: the first is the ground floor, which are usually the first floor, and the second floor is known as the second floor. In addition, there are other floors that are also found in these houses.