# Solid Masonry: Building Code Definition

> How the IRC 2009 define solid masonry, where the wording differs, and which chapters depend on the term.

- Canonical: https://harth.build/resources/glossary/solid-masonry/
- Last updated: 2026-09-07
- Data source: 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.

## Key facts

| Fact | Value |
| --- | --- |
| Defined in | IRC 2009 (2009 editions transcribed in this corpus) |
| Primary source | IRC 2009 Definitions (model text, not a jurisdiction's adopted text) |
| Chapters using the term | 9 (counted across the codes hosted here) |
| Wording identical across codes | Single code (compare before citing one code's wording under another) |

## Direct answer

Solid masonry is a defined term in the International Residential Code (IRC) 2009, in Definitions. The code's own words are: “Load-bearing or nonload-bearing construction using masonry units where the net cross-sectional area of each unit in any plane parallel to the bearing surface is not less than 75 percent of its gross cross-sectional area. Solid masonry units shall conform to ASTM C 55, C 62, C 73, C 145 or C 216.” No other I-Code in this corpus defines it, so the IRC 2009 definition is the one to work from. The term is used in 9 chapters of this corpus, most often in Masonry (IBC 2009), Chimneys and Fireplaces (IRC 2009), Wall Construction (IRC 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](https://nz.linkedin.com/in/barrington), Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.*

## What does this term mean?

**Solid Masonry** — IRC 2009, Definitions:

> Load-bearing or nonload-bearing construction using masonry units where the net cross-sectional area of each unit in any plane parallel to the bearing surface is not less than 75 percent of its gross cross-sectional area. Solid masonry units shall conform to ASTM C 55, C 62, C 73, C 145 or C 216.

![Labeled code-term definition diagram: Solid Masonry: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/solid-masonry/diagram-1344.webp)

*How the IRC 2009 define solid masonry, where the wording differs, and which chapters depend on the term.*

## What must be verified before using this guidance?

**Solid Masonry** is defined once in this corpus, in the [Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/definitions.md) chapter of the International Residential Code (IRC) 2009:

> Load-bearing or nonload-bearing construction using masonry units where the net cross-sectional area of each unit in any plane parallel to the bearing surface is not less than 75 percent of its gross cross-sectional area. Solid masonry units shall conform to ASTM C 55, C 62, C 73, C 145 or C 216.

## Where solid masonry is used in the code

The term appears in 9 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.

| Chapter | Code | Mentions |
| --- | --- | --- |
| [Masonry](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/masonry.md) | IBC 2009 | 47 |
| [Chimneys and Fireplaces](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/chimneys-and-fireplaces.md) | IRC 2009 | 23 |
| [Wall Construction](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/wall-construction.md) | IRC 2009 | 18 |
| [Soils and Foundations](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/soils-and-foundations.md) | IBC 2009 | 14 |
| [Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/definitions.md) | IRC 2009 | 9 |
| [Definitions](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/definitions.md) | IMC 2009 | 4 |
| [Fuel Gas](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/fuel-gas.md) | IRC 2009 | 4 |
| [Foundations](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/foundations.md) | IRC 2009 | 3 |
| [Definitions](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/definitions.md) | IBC 2009 | 2 |

### The term in use

How the code actually writes about solid masonry, quoted from the 2009 text hosted here:

> ASTM C 62 for building brick (solid masonry units made from clay or shale) ;

— [IBC 2009 §2103.2](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/masonry.md)

> A masonry heater is a heating appliance constructed of concrete or solid masonry, hereinafter referred to as masonry, which is designed to absorb and store heat from a solid-fuel fire built in the firebox by routing the exhaust gases through internal heat exchange channels in which the flow path downstream of the firebox may include flow in a horizontal or …

— [IRC 2009 §RI002.1](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/chimneys-and-fireplaces.md)

> Solid masonry walls of one-story dwellings and garages shall not be less than 6 inches (152 mm) in thickness when not greater than 9 feet (2743 mm) in height, provided that when gable construction is used, an additional 6 feet (1829 mm) is permitted to the peak of the gable.

— [IRC 2009 §R606.2.1](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/wall-construction.md)


## The terms solid masonry is built out of

The definition above leans on 3 other defined terms. Each carries its own code definition, and a local amendment to any of them changes what solid masonry covers:

- **[Masonry](https://harth.build/resources/glossary/masonry.md)** — IBC 2009: A built-up construction or combination of building units or materials of clay, shale, concrete, glass, gypsum, stone or other approved units bonded together with or without mortar or grout or other accepted methods of joining.
- **[Solid](https://harth.build/resources/glossary/solid.md)** — IBC 2009: A material that has a melting point, decomposes or sublimes at a temperature greater than 68°F (20°C).
- **[Shall](https://harth.build/resources/glossary/shall.md)** — IRC 2009: The term, when used in the code, is construed as mandatory.

## Solid Masonry: what to open, and in what order

Every row is a document this term depends on. The [ICC code library](https://codes.iccsafe.org/codes) and the [ICC adoption maps](https://www.iccsafe.org/advocacy/code-adoption-maps/) cover the middle rows.

| Check | Where | Confirmed |
| --- | --- | --- |
| Read the definition in the adopted IRC | Definitions | |
| Re-check the requirement that uses it | Masonry (IBC 2009) | |
| Re-check the requirement that uses it | Chimneys and Fireplaces (IRC 2009) | |
| Re-check the requirement that uses it | Wall Construction (IRC 2009) | |
| Re-check the requirement that uses it | Soils and Foundations (IBC 2009) | |
| Confirm the dependent definition | Masonry | |
| Confirm the dependent definition | Solid | |
| Confirm the dependent definition | Shall | |
| 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](https://harth.build/resources/glossary.md)
- [Masonry: Building Code Definition](https://harth.build/resources/glossary/masonry.md)
- [Solid: Building Code Definition](https://harth.build/resources/glossary/solid.md)

## 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](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.

### Source links

- [codes.iccsafe.org](https://codes.iccsafe.org/codes)

- [iccsafe.org](https://www.iccsafe.org/advocacy/code-adoption-maps/)

## Frequently asked questions

### What is the code definition of solid masonry?

The International Residential Code (IRC) 2009 defines it in Definitions as: “Load-bearing or nonload-bearing construction using masonry units where the net cross-sectional area of each unit in any plane parallel to the bearing surface is not less than 75 percent of its gross cross-sectional area. Solid masonry units shall conform to ASTM C 55, C 62, C 73, C 145 or C 216.” 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 solid masonry?

In this corpus the term is used across 9 chapters, led by Masonry 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.

### What is considered a masonry building?

Building is a separate defined term. The IBC 2009 defines it as: “Any structure used or intended for supporting or sheltering any use or occupancy.” That is not the same as solid masonry, which the IRC 2009 defines as “Load-bearing or nonload-bearing construction using masonry units where the net cross-sectional area of each unit in any plane parallel to the bearing surface is not less than 75 percent of its gross cross-sectional area. Solid masonry units shall conform to …” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

### What is a solid masonry unit?

In the 2009 I-Codes hosted here it is a defined term rather than a description. The IRC 2009 states, in Definitions: “Load-bearing or nonload-bearing construction using masonry units where the net cross-sectional area of each unit in any plane parallel to the bearing surface is not less than 75 percent of its gross cross-sectional area. Solid masonry units shall conform to ASTM C 55, C 62, C 73, C 145 or C 216.” It is defined in IRC 2009. It is not the same as Masonry Unit, which the IBC 2009 defines separately as “Brick, tile, stone, glass block or concrete block conforming to the requirements specified in Section 2103.” 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.

---

- Continue in Harth (open this topic in the Harth agent): https://app.harth.build/agent?context=%2Fresources%2Fglossary%2Fsolid-masonry%2F
- View this page in a browser: https://harth.build/resources/glossary/solid-masonry/
- All resources for agents: https://harth.build/llms.txt