Building Code Glossary
Trim: Building Code Definition
How the IBC 2009, IRC 2009 define trim, 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
Trim is a defined term in the International Building Code (IBC) 2009, in Interior Finishes. The code's own words are: “Picture molds, chair rails, baseboards, handrails, door and window frames and similar decorative or protective materials used in fixed applications.” The IRC 2009 carries the same definition word for word, so the term means the same thing in each. The term is used in 39 chapters of this corpus, most often in Interior Finish, Decorative Materials and Furnishings (IFC 2009), Plastic (IBC 2009), Floors (IRC 2009). These pages transcribe the 2009 model text; verify the definition against the edition and amendments your authority having jurisdiction has adopted. Record the jurisdiction, the adopted edition, the application date and any local amendment that rewrites the definition before you use it on a live project, because a term redefined by amendment changes every requirement that depends on it.
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?
Trim — IBC 2009, Interior Finishes:
Picture molds, chair rails, baseboards, handrails, door and window frames and similar decorative or protective materials used in fixed applications.
What must be verified before using this guidance?
Two of the I-Codes in this corpus define Trim, in identical words.
| Code | Where it is defined | Definition |
|---|---|---|
| IBC 2009 | Interior Finishes | Picture molds, chair rails, baseboards, handrails, door and window frames and similar decorative or protective materials used in fixed applications. |
| IRC 2009 | Definitions | Picture molds, chair rails, baseboards, handrails, door and window frames, and similar decorative or protective materials used in fixed applications. |
Where trim is used in the code
The term appears in 39 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.
| Chapter | Code | Mentions |
|---|---|---|
| Interior Finish, Decorative Materials and Furnishings | IFC 2009 | 35 |
| Plastic | IBC 2009 | 30 |
| Floors | IRC 2009 | 19 |
| Interior Finishes | IBC 2009 | 17 |
| Roof-ceiling Construction | IRC 2009 | 16 |
| Exterior Walls | IBC 2009 | 15 |
| Masonry | IBC 2009 | 13 |
| Wood | IBC 2009 | 11 |
| Building Planning | IRC 2009 | 11 |
| Chimneys and Fireplaces | IRC 2009 | 9 |
| Water Supply and Distribution | IRC 2009 | 8 |
| Wall Covering | IRC 2009 | 7 |
27 further chapters mention the term.
The term in use
How the code actually writes about trim, quoted from the 2009 text hosted here:
The provisions of this chapter shall govern interior finish, interior trim, furniture, furnishings, decorative materials and decorative vegetation in buildings.
These provisions shall govern the materials, design, application, construction and installation of foam plastic, foam plastic insulation, plastic veneer, interior plastic finish and trim and light-transmitting plastics.
For buildings in flood hazard areas as established in Section 1612.3, interior finishes, trim and decorative materials below the design flood elevation shall be flood-damage-resistant materials.
Trim: 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 | Interior Finishes | |
| Read the definition in the adopted IRC | Definitions | |
| Re-check the requirement that uses it | Interior Finish, Decorative Materials and Furnishings (IFC 2009) | |
| Re-check the requirement that uses it | Plastic (IBC 2009) | |
| Re-check the requirement that uses it | Floors (IRC 2009) | |
| Re-check the requirement that uses it | Interior Finishes (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
- Flame Spread Index: Building Code Definition
- Smoke-developed Index: Building Code Definition
- Interior Finish: Building Code Definition
- Interior Wall and Ceiling Finish: 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 trim?
The International Building Code (IBC) 2009 defines it in Interior Finishes as: “Picture molds, chair rails, baseboards, handrails, door and window frames and similar decorative or protective materials used in fixed applications.” 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 trim?
In this corpus the term is used across 39 chapters, led by Interior Finish, Decorative Materials and Furnishings in the IFC 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.
What is a trim in a building?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IBC 2009 states, in Interior Finishes: “Picture molds, chair rails, baseboards, handrails, door and window frames and similar decorative or protective materials used in fixed applications.” It is defined in IBC 2009, IRC 2009. It is not the same as Building, which the IBC 2009 defines separately as “Any structure used or intended for supporting or sheltering any use or occupancy.” Because it is a defined term, whatever the adopted edition says it means is what every section using it means — so check Chapter 2 of that edition and any local amendment before relying on this wording.
What does trim code mean?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IBC 2009 states, in Interior Finishes: “Picture molds, chair rails, baseboards, handrails, door and window frames and similar decorative or protective materials used in fixed applications.” It is defined in IBC 2009, IRC 2009. Because it is a defined term, whatever the adopted edition says it means is what every section using it means — so check Chapter 2 of that edition and any local amendment before relying on this wording.
Related pages
- Trap Seal: Building Code Definition
Trap Seal — IRC 2009 definition: The trap seal is the maximum vertical depth of liquid that a trap will retain, measured …
- Trap: Building Code Definition
Trap — IRC 2009 definition: A fitting, either separate or built into a fixture, that provides a liquid seal to prevent …
- Treated Wood: Building Code Definition
Treated Wood — IBC 2009 definition: Wood and wood-based materials that use vacuum-pressure impregnation processes to enhance fire retardant or preservative properties.
- Trouble Signal: Building Code Definition
Trouble Signal — IBC 2009 definition: A signal initiated by the fire alarm system or device indicative of a fault in a …
- Truss Design Drawing: Building Code Definition
Truss Design Drawing — IRC 2009 definition: The graphic depiction of an individual truss, which describes the design and physical characteristics of the …
- Tube Trailer: Building Code Definition
Tube Trailer — IFC 2009 definition: A semitrailer on which a number of tubular gas cylinders have been mounted.