Roofing Codes: A Guide for Safe and Functional Roofs

Oct 15, 2023


Moises V.




October 15, 2023


December 13, 2023

Got Questions?

As an essential part of a building’s integrity, a roof must meet certain standards for safety and functionality, hence roofing codes. We know reading through dense national and international code documents is overwhelming, which is why we’ll help you through building codes in the United States.

At Viking Contractors, we have experience in roofing service repairs, so our roofing contractors are well-acquainted with roofing guidelines. Contact us today; we’re ready to assist you.


Defining Codes for Roofing

They’re prescriptive or performance construction requirements that fall under building codes and relate to roofing. So, they focus on the material, construction, and design of roofs. State and local governments legislate building code requirements to protect a building’s structure, and building inspectors see to their implementation.

In the U.S., most states take model building codes from the International Code Council (ICC), the International Residential Code (IRC) for one and two-family homes, the International Building Code (IBC) for other buildings, the National Fire Protection Association, and the ASTM International. They usually make their own local amendments to these standardized templates.

Some local jurisdictions may have adopted the International Existing Building Code (IEBC), the International Energy Conservation Code (IECC), which is especially important for low roof slopes because of their thermal insulation R-value requirements, and the International Green Construction Code (IGCC).

It’s also important to note that state and local building codes change constantly, and you must be aware of recent amendments to model building codes with the authority that has jurisdiction in your area.

You’ll find information on requirements, inspections, and permits online. Also, the manufacturer’s installation instructions are a good source, as manufacturers are up-to-date with these regulations.


Defining Building Standards

With the work of independent laboratories and industry groups, building standards go hand in hand with building codes. Like model codes, they get altered frequently. We can classify them into three types:

  • Testing Standards: For test methods and minimum approved results
  • Rating standards: For measurement methods between products
  • Design Standards: For criteria for building and roof system design


What Are the Different Roofing Codes?

Foreman holding drawing project and looking for checking home project concept construction working in the construction site, engineer check roof frame with worker.

It’s difficult to sift through lengthy building codes to find the specific requirements that relate to roof systems. We’ll list the main codes and relevant chapters from different codes for buildings and give you the gist of them below.

Roof Assemblies and Rooftop Structures

If you’re unaware, a roof assembly refers to the interacting structural components of a roof, such as a roof deck, thermal barrier or substrate, roof covering, insulation, and vapor retarder.

We consider chapter 15 of the 2018 IBC, titled Roof Assemblies and Rooftop Structures, the main roofing chapter in this building code. It revolves around the design, material, and construction of roof structures and assemblies. It delves into weather-protective barriers and fire-resistant barriers.

Also, it requires you to install a Class A, B, and C fire-resistant roof system if your jurisdiction mandates it or the roof edge is less than three feet from the property line. Most one- and two-family residential dwellings don’t need fire resistance classifications for their roof surfaces.

An older version of this chapter, specifically that of 2015, is also enforced. If you live in a cold climate, you’ll likely face snow accumulating and ice forming along eaves, causing damage and deterring the drainage systems. That’s why installing an ice barrier according to the code is necessary.

Additionally, it divides roof coverings and assemblies into classes according to their resistance into severe, moderate, and light fire exposures. Some building types don’t need a fire rating. The ICC also establishes the required tests for roof cover.

Roof Assemblies

Roof Assemblies is the title of chapter nine of the IRC, 2018. It tackles the design and construction of roof assemblies.

To illustrate, it sets the criteria for wind resistance, roof drainage, above-deck thermal insulation, roof replacement or recovery, roof flashing, and rooftop-mounted photovoltaic systems in roof coverings. It covers different roofing materials, such as asphalt shingles and modified bitumen.

In the 2015 version of the same chapter, you’ll find further requirements for roof construction in cold climates.

Alterations – Level One

According to the ICC, level one alterations “include the removal and replacement or the covering of existing materials, elements, equipment, or fixtures using new materials, elements, equipment, or fixtures that serve the same purpose.”

Chapter seven of the IEBC describes the technical requirements for existing buildings that undergo level one alterations. It details the required improvements to your existing roof. Abiding by it is crucial for roof replacement, roof recovery, flashing reconstruction, and other reroofing projects.

Building Planning

Meeting of engineers and architects in building planning

Chapter three of the IRC discusses the design of wind loads. It can help you determine how much your roof covering can and should handle.

According to section R302.2.2, “Common walls shall extend to and be tight against the exterior sheathing or the roof decking of the exterior walls, or the inside face of exterior walls without stud cavities, and the underside of the roof sheathing.”

Structural Design

Like chapter three of the IRC, chapter 16 of the IBC covers design loads, including wind, rain, and snow. It considers the dead and live loads that your roof will probably have to carry and determines the minimum design requirements accordingly. It also categorizes structures based on the risk they may incur.

Fire and Smoke Protection Features

Chapter seven of the IBC, specifically sections 705.5 and 705.6, gives you the detailed roofing project requirements for fire resistance ratings and points out when fire resistance-rated elements are mandatory. This includes both roof and exterior wall line regulations.

Types of Construction

Chapter six of the 2015 IEBC, specifically section 603.1, maintains that any repairs must maintain the level of fire protection of existing roofing materials.

Energy Efficiency

The main energy code in the U.S. is the IECC, set by the International Code Council (ICC). This model code states the minimum energy efficiency standards for a new roof or an old roof being renovated. The IECC addresses lighting, insulation, HVAC systems, and building envelopes. There are other energy codes that may also apply.


Final Thoughts

To maintain safety and functionality, your roof must abide by international and local codes and standards. They pertain to roofing design, material, construction, sturdiness against wind, rain, and fire, reroofing, alterations, and energy efficiency.

Although grasping these codes can feel overwhelming, working with a professional roofer is the solution. At Viking Contractors, we have years of industry experience and professional knowledge in roof design and installation. 

We’re well-versed in all things codes. Contact us, and you won’t have to worry about local issues or safety hazards.

You might also like
Common Signs Your Roof Needs Repairs


Submit a Comment

Your email address will not be published. Required fields are marked *

Call Now Button