IBC 2009
Page 79
Chapter 5 General Building Heights and Areas
Section 501 General

[F] 501.2 Address Identification New and existing buildings shall be provided with approved address numbers or letters. Each character shall be a minimum 4 inches (102 mm) high and a minimum of 0.5 inch (12.7 mm) wide. They shall be installed on a contrasting background and be plainly visible from the street or road fronting the property. Where access is by means of a private road and the building address cannot be viewed from the public wa~ a monument, pole or other approved sign or means shall be used to identify the structure.