Frost Line : The depth of frost penetration in soil and/or the depth at which the earth will freeze and swell. This depth varies in different parts of the country
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}