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contact | 2009 IBC Hole in Floor Calculator

2009 IBC Hole in Floor Calculator

Jonathan Ochshorn


Directions: Enter values for number of floors connected, occupancy, whether hole is designed as an "atrium," whether hole contains an exit access stair or escalator, and whether the building is sprinklered. This calculator then tells you if your proposed hole is permitted (per 2012 International Building Code). Aside from special rules for a few specialized occupancies (see IBC), there are five main permitted hole categories:

  1. Atrium
  2. Hole connects only 2 floors and is not part of a means of egress
  3. Hole connects only 2 floors with an exit access stairway
  4. Hole contains an exit access stairway or escalator (with some additional required protection)
  5. Within dwelling units (Group R), holes connecting no more than 4 floors are permitted. Within housing units (Group I-3), holes are permitted if four criteria are met.

For additional information and limitations for these categories, read this more detailed discussion of holes in relation to the 2009 International Building Code (IBC). I also have a slightly different calculator based on the 2012 IBC. Figure 1 (below) illustrates a possible hole in a building floor.

Pressing the "update" button is not usually necessary when using the pop-down menus.


sketch showing hole in building floor
Fig. 1. Sectional perspective showing hole in building floor, admittedly exaggerated.