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Table of Contents
Introduction
I put this web page together to make it easier to find sections of the building code that deal with roofing, especially if they aren’t in an obvious place like “Chapter 9 – Roof Assemblies”, which is the main roofing chapter.
This page references the 2018 International Residential Code (IRC). While the 2024 version is the most recent, and several states are still using older versions, the 2018 IRC is in force in many jurisdictions. It’s a good version for general reference, and the roofing sections of the building code don’t usually change too much from one version to the next.
They might change, though, and building code version adoption varies by location, so you should always check with your local building inspection department for the applicable code in your specific area. But even when they do change, the section titles and numbering usually stay the same or at least pretty close, so this guide should help you locate what you’re looking for in any case.
The headings for sections of the code which reference roofing or roof-adjacent aspects of construction are presented on this page in the order they appear in the building code. I also provide links to the actual building code for every chapter below so you can see the actual detailed language of the sections you’re interested in.
You may be looking for a Roofing Guide to the International Building Code.
For a good guide to the entire IRC, consider getting DEWALT 2018 Residential Construction Codes: Complete Handbook.
Searching this page: This is a pretty long page. I recommend using CTRL+F to search for the exact words you’re looking for. Here’s how you do it on desktop and tablet. Here’s how you do it on mobile. If you don’t know this one simple trick, click that link, read the article, and learn how to do it. It will save you a lot of time in the future if you learn how. It’s easy.
Note on Amendments to the International Residential Code
Always check with your local building inspector’s office or website to be certain which version of the building code is in effect in your area. New versions of the model International Residential Code are produced every 3 years, but they are not adopted or put into effect by local authorities every 3 years. In fact, they are not adopted with any consistency from country to country, state to state, or even city to city.
Another important thing to be aware of is the fact that the majority of the governing authorities which adopt the codes do so with amendments. The codes produced by the International Code Council are model codes, which means that they are simply standardized templates that the authorities in actual jurisdictions can use as a foundation for their building codes. Some places will adopt the codes as they are, without amendments, but this is not very common.
Local authorities can (and they do!) add things, remove things, change the language, and make exceptions to the model code, so it’s not enough to simply know which version of the model code has been adopted.
See my article on building codes and roofing for more information.
Chapter 1 Scope and Administration
See the full code for Chapter 1 on the ICC website.
See the full code for Chapter 1 on the UpCodes website.
Section R104 Duties and Powers of the Building Official
- R104.10 Modifications (Note: This section gives the building inspector leeway when it comes to enforcing the code. It allows you to present reasonable requests for code requirement modification if strictly following the code is impractical but the intent and purpose of the code will still be satisfied. – Jack Gray)
- R104.11 Alternative materials, design and methods of construction and equipment
Section R105 Permits
- R105.2 Work exempt from permit
- R105.2.2 Repairs
Section R106 Construction Documents
Chapter 3 Building Planning
See the full code for Chapter 3 on the ICC website.
See the full code for Chapter 3 on the UpCodes website.
Section R301 Design Criteria
(Note: This section mentions roofs over 100 times. – Jack Gray)
- R301.2 Climatic and geographic design criteria
- R301.2.1 Wind design criteria
- R301.2.2.2 Weights of materials
- R301.6 Roof load
Section R302 Fire-Resistant Construction
- R302.2.4 Parapets for townhouses
- R302.2.5 Parapet construction
- R302.2.6 Structural independence
Section R308 Glazing
- R308.6 Skylights and sloped glazing
- R308.6.8 Curbs for skylights
Section R316 Foam Plastic
- R316.5 Specific requirements
- R316.5.2 Roofing
- R316.5.3 Attics
Section R324 Solar Energy Systems
- R324.4 Rooftop-mounted photovoltaic systems
- R324.5 Building-integrated photovoltaic systems
- R324.6 Roof access and pathways
Chapter 4 Foundations
See the full code for Chapter 4 on the ICC website.
See the full code for Chapter 4 on the UpCodes website.
Section R406 Foundation Waterproofing and Dampproofing
Chapter 6 Wall Construction
See the full code for Chapter 6 on the ICC website.
See the full code for Chapter 6 on the UpCodes website.
(Note: This chapter mentions roofs over 200 times, mostly having to do with wall construction requirements which ensure that the walls can support the loads imposed on them. – Jack Gray)
Chapter 7 Wall Covering
See the full code for Chapter 7 on the ICC website.
See the full code for Chapter 7 on the UpCodes website.
Section R703 Exterior Covering
- R703.3 Wall covering nominal thickness and attachments
- R703.3.1 Soffit installation
- R703.3.3 Fasteners
- R703.4 Flashing (Note: Flashing requirements at wall and roof intersections, chimneys. – Jack Gray)
- R703.8 Anchored stone and masonry veneer, general
- R703.8.2 Exterior veneer support
- R703.8.2.2 Support by roof construction
Chapter 8 Roof-Ceiling Construction
See the full code for Chapter 8 on the ICC website.
See the full code for Chapter 8 on the UpCodes website.
(Note: This chapter covers rafters, among other things. It mentions rafters over 200 times and includes rafter span tables. Also covers wood panel (plywood, OSB) roof sheathing requirements. – Jack Gray)
Section R801 General
Section R802 Wood Roof Framing
Section R803 Roof Sheathing
- R803.2 Wood Structural Panel Sheathing (Note: This subsection covers plywood and OSB sheathing. See Table R503.2.1.1 for minimum allowable panel thickness by span and load. – Jack Gray)
Section R804 Cold-Formed Steel Roof Framing
Section R806 Roof Ventilation
Section R807 Attic Access
Chapter 9 Roof Assemblies
See the full code for Chapter 9 on the ICC website.
See the full code for Chapter 9 on the UpCodes website.
(Note: This is the main roofing chapter of the code. In particular, note that the Section R905 subsections for each different type of roofing material address deck requirements, slope, fasteners, underlayment, and flashing for that specific roof type. – Jack Gray)
Section R902 Fire Classification
Section R903 Weather Protection
- R903.2 FlashingR903.2.2 Crickets and Saddles
- R903.3 Coping
- R903.4 Roof drainage
Section R904 Materials
Section R905 Requirements for Roof Coverings
- R905.1 Roof covering application
- R905.1.1 Underlayment
- R905.1.2 Ice barriers (Note: “Ice Barriers” covers the installation requirements for ice and water shield. – Jack Gray)
- R905.2 Asphalt shingles (R905.2.8 Flashing, R905.2.8.2 Valleys, R905.2.8.5 Drip Edge)
- R905.3 Clay and concrete tile
- R905.4 Metal roof shingles
- R905.5 Mineral-surfaced roll roofing
- R905.6 Slate shingles
- R905.7 Wood shingles
- R905.8 Wood shakes
- R905.9 Built-up roofs
- R905.10 Metal roof panels
- R905.11 Modified bitumen roofing
- R905.12 Thermoset single-ply roofing (Note: This section covers EPDM roofing. – Jack Gray)
- R905.13 Thermoplastic single-ply roofing (Note: This section covers TPO and PVC roofing. – Jack Gray)
- R905.14 Sprayed polyurethane foam roofing
- R905.15 Liquid-applied roofing
- R905.16 Photovoltaic shingles
- R905.17 Building-integrated Photovoltaic (BIPV) roof panels applied directly to the roof deck
Section R906 Roof Insulation
Section R907 Rooftop-Mounted Photovoltaic Panel Systems
Section R908 Reroofing
(Note: This section covers the requirements for replacing an existing roof or installing a new roof over an old roof. It also tells you how many roofs (how many layers of roofing) you can put down on top of one another on a building and under what conditions. – Jack Gray)
Chapter 10 Chimneys and Fireplaces
See the full code for Chapter 10 on the ICC website.
See the full code for Chapter 10 on the UpCodes website.
Section R1003 Masonry Chimneys
Section R1005 Factory-Built Chimneys
Chapter 11 [RE] Energy Efficiency
See the full code for Chapter 11 on the ICC website.
See the full code for Chapter 11 on the UpCodes website.
Section N1101 General
- N1101.6 (R202) Defined terms (Note: I recommend reading this subsection first. – Jack Gray)
- N1101.7 (R301.1) Climate zones
- TABLE N1101.7 (R301.1)
- CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID DESIGNATIONS BY STATE, COUNTY AND TERRITORY
- N1101.10 (R303.1) Identification
Section N1102 (R402) Building Thermal Envelope
- N1102.1 (R402.1) General (Prescriptive)
- N1102.1.2 (R402.1.2) Insulation and fenestration criteria
- N1102.1.3 (R402.1.3) R -value computation
- N1102.1.4 (R402.1.4) U- factor alternative
- N1102.2 (R402.2) Specific insulation requirements (Prescriptive)
Section N1109 (R503) Alterations
- N1109.1.1 (R503.1.1) Building envelope
Chapter 18 Chimneys and Vents
See the full code for Chapter 18 on the ICC website.
See the full code for Chapter 18 on the UpCodes website.
Section M1804 Vents
- M1804.2 Termination
- M1804.2.1 Through the roof
Section M1805 Masonry and Factory-Built Chimneys
Chapter 23 Solar Thermal Energy Systems
See the full code for Chapter 23 on the ICC website.
See the full code for Chapter 23 on the UpCodes website.
Section M2301 Solar Thermal Energy Systems
- M2301.2 Design and installation
- M2301.2.1 Access
- M2301.2.2 Collectors and panels
- M2301.2.2.1 Roof-mounted collectors
- M2301.2.9 Roof and wall penetrations
Chapter 24 Fuel Gas
See the full code for Chapter 24 on the ICC website.
See the full code for Chapter 24 on the UpCodes website.
Section G2415 (404) Piping System Installation
- G2415.9 (404.9) Above-ground piping outdoors
Section G2427 (503) Venting of Appliances
- G2427.5 (503.5) Masonry, metal and factory-built chimneys
- G2427.5.3 (503.5.4) Chimney termination
- G2427.6 (503.6) Gas vents
- G2427.6.4 (503.6.5) Gas vent terminations
- G2427.6.6 (503.6.7) Roof terminations
- G2427.7 (503.7) Single-wall metal pipe
- G2427.7.3 (503.7.3) Termination
- G2427.7.5 (503.7.5) Roof penetrations
Chapter 26 General Plumbing Requirements
See the full code for Chapter 26 on the ICC website.
See the full code for Chapter 26 on the UpCodes website.
Section P2607 Waterproofing of Openings
- P2607.1 Pipes penetrating roofs
Chapter 29 Water Supply and Distribution
See the full code for Chapter 29 on the ICC website.
See the full code for Chapter 29 on the UpCodes website.
Chapter 31 Vents
See the full code for Chapter 31 on the ICC website.
See the full code for Chapter 31 on the UpCodes website.
Section P3103 Vent Terminals
- P3103.1 Vent pipes terminating outdoors
- P3103.3 Flashings and sealing
Chapter 44 Referenced Standards
See the full code for Chapter 44 on the ICC website.
See the full code for Chapter 44 on the UpCodes website.
(Note: This chapter includes around 50 standards relevant to roofing. – Jack Gray)
Appendix H – Patio Covers
See Appendix H on the ICC website.
See Appendix H on the UpCodes website.
Appendix J – Existing Buildings and Structures
(Note: This chapter addresses the retrofitting of existing structures. There are a couple of roofing references which may affect reroofing projects. – Jack Gray)
