Plywood

===Softwood===
[[Softwood]] plywood is usually made either of [[Cedrus|cedar]], [[Douglas fir]] or [[spruce]], [[pine]], and [[fir]] (collectively known as [[spruce-pine-fir]] or SPF) or [[redwood]] and is typically used for construction and industrial purposes.<ref>O'Halloran, p. 221.</ref>

The most common dimension is {{convert|1.2|x|2.4|m}} or the slightly larger imperial dimension of 4&nbsp;feet × 8&nbsp;feet. Plies vary in thickness from 1.4&nbsp;mm to 4.3&nbsp;mm. The number of plies—which is always odd—depends on the thickness and grade of the sheet. [[Roofing material|Roofing]] can use the thinner {{convert|5/8|in|mm|adj=on|order=flip}} plywood. Subfloors are at least {{convert|3/4|in|mm|order=flip}} thick, the thickness depending on the distance between floor [[joist]]s. Plywood for flooring applications is often [[tongue and groove]] (T&G); This prevents one board from moving up or down relative to its neighbor, providing a solid-feeling floor when the joints do not lie over joists. T&G plywood is usually found in the {{convert|1/2|to|1|in|mm|adj=on|order=flip}} range.