This architectural drawing is Flue through wooden floor in detail AutoCAD drawing, CAD file, dwg file. A flue is technically any unobstructed vertical space in a chimney that permits smoke from the firebox to exit the house. But as the flue of every chimney must be lined, a chimney liner is also frequently referred to as the flue. Every fireplace, whether it burns wood or gas, has a flue. For more details and information download the drawing file.