Martin County, FL Sign Regulations: Window Signs (2026)

LDR Sec. K, in Article 4, Division 16 (Signs) of the Land Development Regulations, sets the county's only numeric cap on window signage: plastic signs or signs painted on the glass may cover no more than 20 percent of the aggregate glass area, calculated per tenant space or per main use rather than per individual window. The rule reaches beyond signs stuck directly to the glass. Subsection 2 makes clear that a sign displayed from inside the store but visible from the sidewalk or parking lot, such as a poster hung a few feet back from the storefront window, is still a window sign and counts toward the 20 percent cap.

Subsection 3 adds a separate visibility protection: a window sign cannot be placed where it substantially obscures the public's view into the building through the window, regardless of whether it stays under the area cap. Window signs sit within the county's broader sign-illumination and safety framework: any illuminated window sign must still meet the shielding standard of Sec. C, and every sign requires a permit from the Building Director under Sec. 696 unless it falls into an exempt category under Sec. 706, such as hours-of-operation signs limited to two square feet.

Because Sec. K measures against the tenant space's aggregate glass area, a business with several storefront windows can concentrate its signage on fewer panes as long as the total displayed area across all windows doesn't exceed one-fifth of the combined glass.