The many components of the framing system make up the support system for the floors, ceilings, walls, and roof. Most homes are constructed using timber framing and a small percentage using metal. The buildings basic design and location will dictate the type of framing used. In some parts of the country, buildings must be designed with special resistance to earthquakes, winds, or heavy snow. All structures should be built to reduce the effects of shrinkage, warping, fire, and water damage. The majority or sometimes entire framing system is often hidden by the finished materials on the walls, ceilings and floors. The finished materials are inspected carefully to see if they give clues to defects which may not be readily accessible. There are two basic types of framing systems. Both systems must be inspected very carefully for defects such as poor installation, settling, rot, insect damage, and more.