Saddle 4 : A small second roof built behind the back side of a fireplace chimney to divert water around the chimney. Also, the plate at the bottom of some - usually exterior - door openings. Sometimes called a threshold
Frank Mayhue, Home Building Manual, Construction Glossary from Home Building Manual, USA 1999. http://www.homebuildingmanual.com/Glossary.htm, (Home Bulid - Amer) {518}
Complete Design, Inc. (Construction Design Specialists), Dictionary of Construction Terminology, Washington, USA 2015. http://completedesign.cc/client-resources/dictiona ry-of-construction-terminology, (Const - Amer) {836}