Townhouses are a single-family dwelling unit constructed in a group of 3 or more attached units in which each unit extends from foundation to roof and with open space on at least 2 sides.
Common Wall Requirements
The common wall between the units must be 1 2-hour fire wall or 2 1-hour fire walls construction and must be continuous from foundation to roof diaphragm and must be fire protected at the roof diaphragm for 4 feet out on both sides of the wall.
Townhouses that meet the definition shall be reviewed under the current International Residential Code (IRC). The submittal process for obtaining a building permit for a townhouse is the same as for a single-family residence.