Subflooring is the base floor beneath a finished floor which supports the finished floor and provides the strength and the durability. Well installed subflooring will prevent the creaks and other noises that are often heard in floors.
The subflooring might also be a conduit area for features of the floor, such as heating or air conditioning ducts. In some cases, an electrical panel grid which provides direct overall floor heating will be installed along with the subflooring, usually as an inherent feature of it.
Different Types of Subflooring
Subflooring can be made of a variety of materials, though most subflooring is made of wood. Plywood subflooring is the most common subflooring. Plywood subflooring should be least ¾ inch thick, and laid across the floor joists and nailed or screwed.
Plank subflooring is a stronger type. Plank subflooring is constructed sing 4X8 inch planks, ¾ inch thick, and secured to the floor frame joists by nailing or using deck screws.
Source: www.DoItYourself.com