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Building codes, AHJs, permitting, and plan review — explained for architects, engineers, and designers.

What Occupancy Classification Really Tells You About a Space
Code Explainers

What Occupancy Classification Really Tells You About a Space

The occupancy label on a plan classifies the type of use it is not the headcount. Learn how classification and occupant load work together to drive egress and fire protection.

InstaPreView · July 18, 2026
Window Egress for Residential Buildings: Does It Change Nationwide, or Is It Always the Same?
Code Explainers

Window Egress for Residential Buildings: Does It Change Nationwide, or Is It Always the Same?

Residential egress window rules are nearly uniform nationwide because most jurisdictions adopt the IRC, but editions and local amendments shift the details. Here are the numbers, code anchors, and the mistakes reviewers catch.

InstaPreView · July 16, 2026
TDLR in Texas: What It Is and Why It Matters for Your Project
Code Explainers

TDLR in Texas: What It Is and Why It Matters for Your Project

TDLR administers Texas accessibility rules through the TAS and the Architectural Barriers program. Here's what triggers registration, the role of a RAS, and the costly mistake reviewers see most.

InstaPreView · July 16, 2026
Code Explainers

Understanding Occupancy Separation Under IBC 508: Mixed-Use Made Manageable

IBC 508 offers three paths for mixed occupancies—accessory, nonseparated, and separated. Here's how each affects allowable area and fire ratings, plus the classification mistakes plan reviewers catch most often.

InstaPreView · July 16, 2026
AHJ & Permitting

What Is an AHJ (Authority Having Jurisdiction)?

Authority Having Jurisdiction is the office with the final say on your permit. Here's why their adopted edition and local amendments — not the model code — are the rules that actually govern your set.

InstaPreView · July 15, 2026