Home Improvement

2024 IRC Building Code Changes Every DIYer Should Know

By Hods Published

Building codes may not be the most exciting topic in the DIY world, but they directly affect every project that requires a permit. The 2024 International Residential Code (IRC) introduced several changes that are now being adopted by states and municipalities across the country. If you are building a deck, framing a wall, replacing siding, or running new electrical circuits, these updates affect you.

2024 IRC Building Code Changes Every DIYer Should Know

What Is the IRC and Why It Matters

The International Residential Code is the national model construction code for one- and two-family dwellings, published by the International Code Council (ICC) and updated every three years [1]. States and local jurisdictions adopt the IRC either in full or with amendments, meaning the exact rules in your area may differ slightly. However, the IRC sets the baseline that most building departments follow.

The ICC is currently in its 2024-2026 code development cycle, working toward the 2027 editions [2]. Meanwhile, the 2024 IRC is rolling out across the country, with states like California implementing their version (the 2025 CRC, based on the 2024 IRC) effective January 1, 2026 [3].

The ICC has also announced a holistic review of the IRC through a new Board IRC Review Committee (BIRC), aimed at identifying changes that reduce construction costs and simplify the code without weakening life safety requirements [4]. This is good news for DIYers who have long felt that code complexity makes permitting intimidating.

Deck Construction Updates

Decks are one of the most common DIY building projects, and the 2024 IRC made several clarifications that affect how you plan and build.

Lumber Requirements

The 2024 code clarifies that all joists, beams, posts, decking, and stair stringers for exterior decks must be made from either pressure-treated wood or naturally durable species such as redwood, cedar, black locust, or black walnut [5]. Sapwood cannot make up more than 10 percent of each face of the lumber. This is not entirely new, but the 2024 code spells it out more explicitly, which means inspectors will be looking more closely.

If you are planning a deck repair project, check every piece of lumber you install against these requirements.

Ledger Flashing

The 2024 IRC introduced detailed flashing requirements for deck ledger connections. Flashing must be installed flush to the weather-resistive barrier (WRB) and extend at least 2 inches above the ledger [5]. Improper ledger flashing is one of the leading causes of deck failures, so this codification of best practices is a welcome change.

Guard and Handrail Requirements

Guards on decks and porches must be at least 36 inches high. Handrails on stairs must be between 34 and 38 inches high. Baluster or cable spacing cannot exceed 4 inches, and guards must resist a 200-pound load [5]. These numbers have not changed dramatically, but the 2024 code consolidates them for clarity.

Stair Landing Exception for Exterior Decks

Here is a change that will save some DIYers headaches. The 2024 IRC includes a new exception for exterior stairway width at the bottom landing. If the stairway serves a deck, porch, or patio and has three or fewer risers, and if no handrail is required, the bottom landing can be only 36 inches wide [5]. This exception does not apply to stairs serving required egress doors.

This is particularly useful for low-profile decks with just a couple of steps down to a patio. Previously, meeting the full landing width requirement often meant pouring more concrete than seemed necessary.

Vinyl Siding Installation Standards

The 2024 IRC now codifies key vinyl siding installation practices. New provisions require manufacturer-approved starter strips at the initial course and utility trim under windows and other areas where the nail hem is cut [1]. This ensures proper attachment and wind performance.

For DIYers tackling siding work, this means following manufacturer instructions is no longer just best practice but code requirement. Make sure every starter strip is the correct model for your siding brand, and install utility trim at every cut edge.

Wind Design Updates

Working with the American Society of Civil Engineers (ASCE) and the National Council of Structural Engineers Associations (NCSEA), the Insurance Institute for Business and Home Safety (IBHS) helped update the IRC’s wind design requirements to align with ASCE 7-22 [1]. Changes include an updated wind speed map, revised simplified component and cladding loads table, and new roof zone figures.

If you live in a hurricane-prone or high-wind area, these updated maps may change the fastener schedules and sheathing requirements for your projects. Check with your local building department before starting any roofing or sheathing work.

Electrical Requirements to Watch

While the 2024 IRC electrical chapters did not see sweeping changes, ongoing trends continue to tighten safety requirements. GFCI protection is now expected near all deck areas, and the 2025 California code adds updated EV charging provisions and enhanced energy efficiency standards [3].

If you are adding outlets to a workshop electrical setup or installing a new circuit, always verify current local requirements. Electrical code violations are among the most common inspection failures.

Always hire a licensed electrician for panel work, new circuit installations, and any project that involves working inside your electrical panel. A mistake with electrical work can cause a fire or electrocution.

How to Stay Current with Code Changes

Building codes are adopted at different rates across the country. Some states move to the latest code within a year, while others lag by one or two cycles. Here is how to stay informed:

  1. Check your local building department website for the currently adopted code edition
  2. Pull a permit before starting any project that involves structural, electrical, or plumbing work
  3. Talk to your building inspector early in the planning process; most are happy to answer questions before you start work
  4. Review the NAHB significant changes document for the 2024 IRC, which summarizes the most impactful updates in plain language [6]

Do not assume that a YouTube tutorial or a project guide from five years ago reflects current code. Codes evolve, and what passed inspection in 2020 may not pass today.

What Is Coming Next

The ICC’s 2024-2026 development cycle means the 2027 code edition is already taking shape. Year one covers Group A Codes, year two covers Group B Codes, and year three brings joint public comment hearings and the online governmental consensus vote [2]. If you want to influence future codes, NAHB and ICC both accept public comments during the development process.

For now, focus on understanding the 2024 IRC changes as they roll out in your area. When in doubt, over-build rather than under-build. Meeting code is the minimum, and a stronger deck, a better-flashed ledger, and properly installed siding will outlast the code minimum by decades.

Sources

  1. ANSI Blog. “What’s New in the 2024 International Residential Code?” https://blog.ansi.org/ansi/2024-international-residential-code-irc-icc-codes/
  2. ICC. “2024/2025/2026 International Code Council Code Development Schedule.” https://www.iccsafe.org/building-safety-journal/bsj-hits/2024-2025-2026-international-code-council-code-development-schedule-now-available/
  3. PlanCheck Solver. “2025 California Residential Code (CRC) Changes.” https://www.planchecksolver.com/codes/california-residential-2025
  4. NAHB. “NAHB Requests Member Feedback on ICC Review of International Residential Code.” https://www.nahb.org/blog/2025/10/irc-review-member-feedback
  5. JLC Online. “What’s Ahead for Decks in the 2024 IRC.” https://www.jlconline.com/deck-builder/whats-ahead-for-decks-in-the-2024-irc_o
  6. NAHB. “2024 Significant Code Changes for the IRC.” https://www.nahb.org/-/media/NAHB/advocacy/docs/top-priorities/codes/code-adoption/signficant-code-changes-2024-irc.pdf