Terms of Use & Building Code Disclaimer

Last updated: November 12, 2026

The calculators, 2D elevation blueprints, hook-tape layout lists, and IRC Table R507.5 span lookups provided by RailSpan Studio are offered free of charge for preliminary carpentry planning and educational estimation only.

Verify Local Building Codes & Permits

While our tools reference standard International Residential Code (IRC) provisions—including the 4-inch guardrail sphere rule (IRC R312.1.3) and deck beam span tables (IRC R507.5)—municipalities, counties, and HOAs frequently adopt stricter local amendments (such as snow loads exceeding 40 psf, seismic lateral bracing, coastal wind ratings, or pool-barrier rules). Always confirm final dimensions with your local building inspector or a licensed structural engineer before cutting materials or pouring concrete footings.