What material is primarily used for solid roof decking?

Plywood is primarily used for solid roof decking due to its strength, durability, and versatility. It consists of multiple layers of wood veneer that are glued together, with the grains of each layer oriented in opposite directions, which provides excellent structural integrity and resistance to warping. This makes plywood a suitable material for roofing applications, where it can support the weight of roofing materials and withstand environmental stressors such as rain, snow, and wind.

Plywood also has the advantage of being readily available and easy to cut and install, which makes it a preferred choice among contractors. Its ability to provide a solid, reliable surface for attaching shingles or other roofing materials further reinforces its popularity in residential construction.

Other materials, such as chipboard, are not as strong or durable for roofing applications, while straw board and composite board may not provide the structural support needed for solid roof decking. Thus, plywood stands out as the primary choice for this purpose.