Search any building-code question and you'll find people confidently contradicting each other. Often they're both right. The reason is something the model codes don't advertise: the rule that applies to you depends on where you build.
Model codes vs. adopted codes
Organizations publish model codes — the residential, building, electrical, and energy codes — on a multi-year cycle. But a model code is just a template until a state, county, or city adopts it into law. Different places adopt different editions, and they adopt them at different times. So one jurisdiction may be enforcing an older edition while a neighbor enforces a newer one.
Then the amendments
On top of the adopted edition, local governments amend. They add requirements for local conditions — seismic zones, frost depth, wildfire, high wind, floodplain — and sometimes strike or soften provisions that don't fit the area. The amended, adopted code is the one that actually governs your project, and it can differ from the model text in ways that matter.
- Which edition your jurisdiction adopted — it may not be the newest.
- Local amendments — extra requirements or changes specific to your area.
- How a provision is interpreted by your local inspector, who has the final say on the ground.
What this means for you
Treat a generic code answer as a strong starting point, not a final ruling. Before you build, confirm the adopted edition and any local amendments with your building department. That's exactly why every answer here ends with the same line — verify with your AHJ — and why a tool that knows your jurisdiction beats one that quotes a code that may not apply where you stand.
The code isn't one book. It's whichever edition your town adopted, plus whatever they changed — verify before you build.