Steel frame construction uses large steel columns and rafters (typically called “frames”) that are set anywhere from 20’ to 30’ o. c. Then a series of steel zee purlins (roof) and steel zee girts (walls) are fastended between or over top of these frames of which is covered with steel panels.  This type of construction is becomes more practical when you are looking to obtain spans that are larger than 80’ in width. Wood frame construction uses wood posts that connect to pre-engineered wood trusses that are set anywhere from 4’ to 12’ o. c. Then a series of wood purlins (roof) and wood girts (walls) are fastened between or over top of posts and trusses of which is covered with steel panelsWood frame construction is generally more cost effective with buildings that require spans 80’ or less.  This is where wood has met its capacity and steel has really only started with its capacity