In reading these weeks, Ching went deep with many of the basic building materials that we are using today. Some of them are made of wood, masonry, concrete, steel and stone. Because of its qualities, each material has its own advantages when used and some or used instead of others. Concrete is made by mixing different aggregates with enough water and in combination with steel is very useful. Masonry is basically stonework and when stacked on top of each other, it is very useful. Therefore, steel has strength and hardness qualities for making it more preferable with concrete. Wood is good for convenience where the material itself is strong, durable, lightweight and easy to use. Stone is a combination of many materials and it needs to fulfill all these requirements in order to become stone: strength; hardness; durability; work ability; density and appearance. As stated before each building material, certain criteria must be met to select the use when building a structure.