Houses of the higher class were referred to as "Domus," and typically had an atrium, bedrooms and kitchens on one side, and a garden, known as "hortus," at the back of the house. The lower class lived in apartments, which were small, dark rooms with no windows or doors where they could be under the control of their landlord. A house's location was important because it determined how much sunlight it received and thus what kind of roof it needed. There were three types of roofs: flat, sloping and turreted. Flat roofs were used for houses that weren't subject to excessive weather conditions because they didn't need additional protection from the elements. Sloping roofs were recommended for areas where there was heavy rainfall because they could drain away any excess water. Turreted roofs were used for houses in warmer climates or when wood was scarce because they used up less material than other types of roofs and also helped retain heat during cold seasons. The houses in Pompeii were made of stone and brick and usually had three floors. The first floor was made of stone or concrete; the second floor, of wooden beams supported by columns; and the third floor, which could be reached by an elevator, was made of plaster or lime mortar between the stones or bricks. Each house had its own well-maintained yard filled with trees and shrubs.