ToolBase.org logo
Skip to Main Content  
Advanced Search  
The Home Building Industry's Technical Information Resource

Back to Standard View
Building SystemsHome Building TopicsDesign & Construction GuidesBest PracticesConstruction Methods
Adobe Acrobat Reader required for PDF documents

PDF documents require the free Adobe Reader.

All PDF documents open in a new browser window. Close the browser window to return to the site.

In which regions of the United States are houses required to be designed for earthquake loads?

Question:

In which regions of the United States are houses required to be designed for earthquake loads?

Answer:

Special seismic provisions of the International Residential Code (IRC) are required for detached one- and two-family houses located in Seismic Design Categories (SDC) D1 and D2 and townhouses located in SDC C, D1, and D2. All houses located in SDC E and portions of the houses that have irregular configuration in accordance with Section R301.2.2.2.2 of 2003 IRC are required to be engineered. Examples of irregularities include vertical wall offsets, floors with openings exceeding 12 feet, offsets in floor levels in the same story, etc. Seismic Design Categories are defined in Figure R301.2(2) of the 2003 IRC.