Building Code Glossary
Naturally Durable Wood: Building Code Definition
How the IBC 2009, IRC 2009 define naturally durable wood, where the wording differs, and which chapters depend on the term.
On this page
Last updated September 7, 2026 · Definitions quoted from the 2009 International Codes as transcribed in this site's building-codes collection, with the source chapter linked for each quotation. Usage counts are computed over the chapters hosted here, one copy per code. The [ICC code library](https://codes.iccsafe.org/codes) publishes the current model text and the [ICC adoption maps](https://www.iccsafe.org/advocacy/code-adoption-maps/) show which edition a jurisdiction has adopted; those sources control.
Direct answer
Naturally durable wood is a defined term in the International Building Code (IBC) 2009, in Wood. The code's own words are: “The heartwood of the following species with the exception that an occasional piece with corner sapwood is permitted if 90 percent or more of the width of each side on which it occurs is heartwood.” The IRC 2009 carries the same definition word for word, so the term means the same thing in each. The term is used in 6 chapters of this corpus, most often in Roof Assemblies and Rooftop Structures (IBC 2009), Roof Assemblies (IRC 2009), Wood (IBC 2009). These pages transcribe the 2009 model text; verify the definition against the edition and amendments your authority having jurisdiction has adopted.
Content and cited inputs reviewed by Scott Barrington, Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.
What does this term mean?
Naturally Durable Wood — IBC 2009, Wood:
The heartwood of the following species with the exception that an occasional piece with corner sapwood is permitted if 90 percent or more of the width of each side on which it occurs is heartwood.
What must be verified before using this guidance?
Two of the I-Codes in this corpus define Naturally Durable Wood, in identical words.
| Code | Where it is defined | Definition |
|---|---|---|
| IBC 2009 | Wood | The heartwood of the following species with the exception that an occasional piece with corner sapwood is permitted if 90 percent or more of the width of each side on which it occurs is heartwood. |
| IRC 2009 | Definitions | The heartwood of the following species with the exception that an occasional piece with corner sapwood is permitted if 90 percent or more of the width of each side on which it occurs is heartwood. |
Where naturally durable wood is used in the code
The term appears in 6 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.
| Chapter | Code | Mentions |
|---|---|---|
| Roof Assemblies and Rooftop Structures | IBC 2009 | 4 |
| Roof Assemblies | IRC 2009 | 4 |
| Wood | IBC 2009 | 3 |
| Definitions | IBC 2009 | 1 |
| Building Planning | IRC 2009 | 1 |
| Definitions | IRC 2009 | 1 |
The term in use
How the code actually writes about naturally durable wood, quoted from the 2009 text hosted here:
Wood shingles shall be of naturally durable wood and comply with the requirements of Table 1507.8.5.
Wood shingles shall be of naturally durable wood and comply with the requirements of Table R905.7.4.
Wood used above ground in the locations specified in Sections 2304.11 .2.1 through 2304.11.2.7, 2304.11.3 and 2304.11.5 shall be naturally durable wood or preservative-treated wood using water-borne preservatives, in accordance with AWPA Ul (Commodity Specifications A or F) for above-ground use.
Naturally Durable Wood: what to open, and in what order
Every row is a document this term depends on. The ICC code library and the ICC adoption maps cover the middle rows.
| Check | Where | Confirmed |
|---|---|---|
| Read the definition in the adopted IBC | Wood | |
| Read the definition in the adopted IRC | Definitions | |
| Re-check the requirement that uses it | Roof Assemblies and Rooftop Structures (IBC 2009) | |
| Re-check the requirement that uses it | Roof Assemblies (IRC 2009) | |
| Re-check the requirement that uses it | Wood (IBC 2009) | |
| Re-check the requirement that uses it | Definitions (IBC 2009) | |
| Local amendment to any of the above | Jurisdiction's amendment list |
A research aid, not a code determination. The authority having jurisdiction decides which edition and which amendments apply.
Where can you explore related guidance?
- Explore all glossary guidance
- Wood Structural Panel: Building Code Definition
- Treated Wood: Building Code Definition
- Shear Wall: Building Code Definition
- Braced Wall Panel: Building Code Definition
Sources and method
Definitions quoted from the 2009 International Codes as transcribed in this site's building-codes collection, with the source chapter linked for each quotation. Usage counts are computed over the chapters hosted here, one copy per code. The ICC code library publishes the current model text and the ICC adoption maps show which edition a jurisdiction has adopted; those sources control.
Source links
Frequently asked questions
What is the code definition of naturally durable wood?
The International Building Code (IBC) 2009 defines it in Wood as: “The heartwood of the following species with the exception that an occasional piece with corner sapwood is permitted if 90 percent or more of the width of each side on which it occurs is heartwood.” The 2009 model text is reproduced here; the definition that binds your project is the one in the edition your jurisdiction has adopted, as amended locally.
Which parts of the code depend on naturally durable wood?
In this corpus the term is used across 6 chapters, led by Roof Assemblies and Rooftop Structures in the IBC 2009. Those are the sections whose scope moves if the definition is amended locally, so read them together with Chapter 2 rather than on their own.
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