Errata or supplement? How to actually read a Title 24 change

Open the back of your Title 24 codebook and you'll find a stack of beige pages that don't match the rest of the binder. Flip through the chapters and you'll see thin vertical bars running down the right margin next to certain paragraphs. Most people in the trade have learned to ignore both. They are actually the most honest part of the book — they tell you exactly what the state changed, and where.

Here's the thing: a code isn't a finished object. It ships, and then it gets patched. The 2025 Triennial Edition of Title 24 took effect statewide on January 1, 2026 — and the corrections were already in motion. Reading them is a skill, and it's mostly vocabulary.

Errata, supplement, buff pages — not synonyms

An erratum corrects errors that were already in the adopted code: a typo, a broken cross-reference, a number printed wrong. It introduces no new policy. By definition an erratum is non-substantive — which means no new requirement, not no real change. A decimal point in the wrong place is plenty real.

A supplement is a different animal: a separate instrument, published on its own track, rather than a correction to the printing you already own. An erratum fixes the text in your book; a supplement is its own document.

Buff pages are just the delivery mechanism — the tan-tinted replacement sheets you physically pull and swap into a three-ring codebook. The Building Standards Commission announced the January batch as the "2025 Title 24 Triennial Code Adoption Cycle Errata (buff pages)." If your binder doesn't have them inserted, your book is quietly out of date.

January 2026: one date, two instruments

This cycle is the perfect teaching case, because two different things landed on the same effective date.

The errata came through BSC Information Bulletin 26-01: Errata, published March 3, 2026, with corrections effective and enforceable as of January 1, 2026. It covers ten books — Parts 2 (Volumes 1 and 2), 2.5, 3, 4, 5, 6, 9, 10, and 11: the Building, Residential, Electrical, Mechanical, Plumbing, Energy, Fire, Existing Building, and Green (CALGreen) codes.

Sitting right next to it on the BSC Codes page is Part 7, the California Wildland-Urban Interface Code — carrying a separate Emergency Supplement, also effective January 1, 2026. It is not one of the errata in IB 26-01. Same date, different instrument. Treat the Part 7 supplement as "part of the errata" and you'll go looking in the wrong document for what changed.

And three books changed nothing this round: Parts 1, 8, and 12 have no errata listed for the 2025 edition.

How to tell which sections actually moved

A buff page reprints a whole sheet, but most of what's on it is unchanged. Five signals tell you what the state actually touched:

1. The Revision Record — the front page of each erratum lists the exact buff pages being replaced.
2. The History Note Appendix (the HIST pages) — a plain-prose statement of the official action and its scope, per part.
3. The Matrix Adoption Tables — section IDs printed in italics flag amended sections.
4. Change bars — the vertical || or > marks in the right margin point at the specific paragraph or table row that changed.
5. IB 26-01's "Noteworthy Topics" — the BSC's own narrative of the headline corrections.

A section merely reprinted unchanged on a buff page is not a change. That's the whole trick: the page swap is the packaging; the markers tell you the content.

Verified against the 2025 California Electrical Code errata (Part 3, effective January 2026): the History Note describes it as an "Erratum to correct editorial errors in the Preface, Article 89, Chapters 1, 2, 3, 4, 5, 7, Informative Annex C, and Index." That one sentence is your map to where the changes live.

Is your copy current?

• Binder and print holders: confirm the buff replacement pages are physically inserted. A pristine first printing is, quietly, wrong.
• PDF and online users: the corrected files aren't in one place. The bulletin lives on dgs.ca.gov, several parts on iccsafe.org, and the Mechanical and Plumbing packets on iapmo.org. Pull each part's errata and match the dated corrections to your copy.

When the answer affects a real submittal, confirm the current text with your authority having jurisdiction. The version you're reading matters as much as the section number you cite.

What CrossBeam does with it

CrossBeam tracks each cycle's corrections and reads plans against the current code text — the version with the January 2026 errata applied, with the Part 7 emergency supplement kept straight as its own instrument. So a submittal is measured against what the code says now, not against a first printing that's already been patched.