Exterior · definition
The code-required barrier on decks above a set height (commonly 30 in.), with height and infill spacing (4 in. sphere rule) set by code.
Source: Decks.com — Deck Railing Codes
Where this term lands on a Columbus budget
The cost pages carry the current local ranges, and the guides explain what moves them. A published range becomes a project number only after someone looks at the site.