Siding is the protective material attached to the exterior side of a wall, building or house. Just like the roof does, it forms the first line of defense from the outside. The siding material and style can enhance or take away from the building’s beauty. There is a wide variety of materials to side with, each with its own benefits and drawbacks. Most siding consists of pieces of weather-resistant material that are smaller than the wall they cover, to allow for expansion and contraction of the materials due to moisture and temperature changes.