Roof-Top Uses Above the Story Limit - A Change is Coming

Earlier this year I wrote about the challenges in some jurisdictions with allowing roof-top amenity deck areas above the building's allowable story limit. Some jurisdictions allow roof-top amenity spaces above the allowable story limit of the building provided the roof area is subdivided into distinct small deck areas each not more than 750 square feet in area or containing an occupant load of less than 50 (these conditions relate directly to the small assembly occupancy provisions of IBC which allow small assembly areas to be considered Group B or part of the primary occupancy of the building). These types of conditions can affect the functionality, architecture, and marketability of a project.

Good News!

The 2018 International Building Code (IBC) has approved two code changes that clarify how to classify roof-top uses without including them in the building’s overall number of stories. The 2018 IBC includes two code changes which help to clarify this matter.

Additional language to IBC Section 302.1 (Group A occupancy definition) clarifies that occupied roofs are classified in the group that the roof use most resembles (e.g., a roof used for lounging, outdoor dining, and pool area would most resemble a Group A use):

"Occupied roofs shall be classified in the group that the occupancy most nearly resembles, according to the fire safety and relative hazard, and shall comply with Section 503.1.4."

IBC Section 503.1.4 is a new code requirement that describes when an occupied roof needs to be considered as an occupancy for purposes of maximum allowable number of stories above grade, and provides options for not requiring the occupied roof to be included in the building’s number of stories:

503.1.4 Occupied roofs. A roof level or portion thereof shall be permitted to be used as an occupied roof provided the occupancy of the roof is an occupancy that is permitted by Table 504.4 for the story immediately below the roof. The area of the occupied roofs shall not be included in the building area as regulated by Section 506.

Exceptions:

1. The occupancy located on an occupied roof shall not be limited to the occupancies allowed on the story immediately below the roof where the building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 and occupant notification in accordance with Section 907.5 is provided in the area of the occupied roof.

2. Assembly occupancies shall be permitted on roofs of open parking spaces of Type I or Type II construction, in accordance with the exception to Section 903.2.1.6.

Since most new buildings are required to be protected by an automatic sprinkler system, exception 1 to Section 503.1.4, will now allow occupied roofs above the building's story limit and without restrictions on the size or type of use. This exception provides approving agencies a definitive code path to allow roof-top uses and provides maximum flexibility to both developers and architects alike.

While the 2019 California Building Code (effective 01/01/2020) is not yet effective, we are hopeful that these IBC code changes will be adopted at the State level during the triennial code adoption cycle process currently taking place.

YCI recently obtained approval to allow a large Group A assembly roof-top pool and deck area above the story limit of a Type III building in the City of Long Beach using the new 2018 IBC code change as part of the equivalent considerations. Contact us at 310.367.6857 or email us at info@younghusband-consulting.com to discuss solution strategies to address your project code challenges.