Today most of the houses are built with two tiers, since the cost of land has increased highly. Also two storied houses help in maximum utilization of space. Building more rooms in the first floor gives more space and comfort to the in mates. While building a 1st floor for a house, the north eastern corner is the most ideal to build stair case. Bedrooms, study area, hall etc. can be built on the first floor as in the ground floor.
Rooms should be planned by following the rules of vastu shastra. The roof height of the rooms should be taken care of as the roof height of the rooms in the 1st floor should not exceed the height of the rooms of the ground floor. Slanting roof in the western and eastern direction is ideal. First floor of the house always gives you good air and also lets you enjoy the beauty of nature around.