A Slide Bolt on an Exit Door Is a Mount Job: Measure, Mount, and Test in Order

A slide bolt set high on an exit door looks like a small job, and it is a small job, but it has a fixed order. Each step sets up the next, and skipping the test is how a bolt fails when it is needed most. Work through the steps in this order.

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Step one: check the exit before you add anything

Before you drill, open the door the way she would in a hurry. Can it be opened from inside in one motion, without a key, a tool, or a second person? A bolt that makes the door harder to open from inside is a hazard, not a safeguard. Ask your local fire office or building inspector how an exit door must open in your home, and keep that answer with your install notes.

Step two: pick the height and the side

Choose a spot a standing adult can reach without a stool, set above the height where she would reach by habit. Mark the position on the door and on the frame. Check that the bolt will land in the frame at that height and not in the trim or the gap between frame and door, because a bolt that misses the frame holds nothing.

Step three: mount the parts in the right order

Mount the frame half first, since it takes the load, and make sure its screws go into solid wood rather than only into trim. If the frame is old or soft, have a handy person or a contractor look at it before you go further. Then mount the sliding half on the door with the bolt closed, so the two halves line up when you test.

Step four: test it closed, then open

Close the door and slide the bolt. Check that it seats fully into the frame and does not bind. Then open the bolt from inside, the way you would in a hurry, with the lights off. Do this three times. If the bolt sticks, stop and adjust before you go on. A bolt that is hard to open from inside needs adjusting before anyone relies on it.

Step five: hand off the knowledge

Tell everyone who visits or stays overnight that the bolt exists, where it is, and how to open it from inside. Write the steps on a card near the door. Then go back through the Start Here order to see where this step fits into the first evening.