Having a deadbolt on your door in a downtown building is not a bad idea. You do, however, need to be careful about how you go about it. In general, the code says you can’t have a deadlock system of any kind. The code also provides a lot of exceptions.

These exceptions can make this code confusing. They have also changed the language of this code in recent years, so it pays to reference the most recent International Building Code (IBC) book to your building official. He or she may tell you that the city has not adopted the most recent IBC book, but most officials are open to an updated system.

In general, for most main level building use types in the downtown district, an exception exists that will allow a deadbolt lock if you have fewer than 300 occupants, and you provide a sign stating “THIS DOOR TO REMAIN UNLOCKED WHEN THIS SPACE IS OCCUPIED” in 1” high letters directly next to or on the door. This kind of lock is usually a keyed deadbolt on both sides of the lock for full security reasons.

For double doors, the deadbolt lock gets a bit more complicated. Usually in this situation, one door is meant to be stationary, thus nonfunctional, unless manually disengaged and held open. This way, the operable door has a fixed side for the deadbolt to engage. If you have this situation, please refer directly to your building official for a ruling, as the code has too many options to include in this article.

For the upper level apartment units, a door providing a deadbolt locking mechanism can only be used if the occupant load is 10 or less. This typically covers a 3-bedroom unit easily. The lock on the inside cannot be operated by a key or other tool in order to get out of the building. Most deadbolts have a simple turn knob to unlock the door. Stay with this design.

To further complicate the deadbolt locking system, let’s talk about putting one at the bottom of the staircase at the sidewalk level. I have had differing opinions on locking this door with building officials. The safe answer is that it is okay to have a deadbolt lock at this location if all the units it feeds have an occupant load of 10 or less. We are basically using the same code clause as the paragraph above that feeds an individual unit. If your bottom of stairs door feeds more than 10 occupants, I recommend you put in full panic hardware that does not require a deadbolt lock to properly secure your building.