California Roofing Codes for New Commercial Properties

Perhaps nowhere in the United States do commercial property owners and managers have more compliance challenges with roofing codes than California. Not only must commercial roofing systems stand up to the typical elements such as weather, heat, UV exposure, etc., but they must also do so while complying with some of the strictest green building codes in the U.S.

In addition to this, California’s location along the Pacific Rim (the so-called “Ring of Fire”) means buildings must also be constructed to resist cataclysmic events like earthquakes and tsunamis – and, thanks to California’s hot, dry climate, wildfires. That’s a lot to consider!

Suffice it to say if you are a commercial property owner/manager, or if you’re looking to build a new commercial property or install a new commercial roof, you have a lot to think about – and California’s strict building codes are designed to make sure no priority is overlooked. Let’s take a closer look at California’s unique roofing codes for commercial buildings to help you be informed.

Why Do Commercial Building Codes Exist?

Most building codes (both residential and commercial) are designed to ensure uniformity (e.g., in structure in appearance), to ensure public safety, or both. Building codes for commercial structures can be especially stringent because commercial buildings have a greater potential to impact people and/or affect the environment – either for good or for bad. Thus, commercial building codes are designed to minimize hazard risks to the building’s occupants, the surrounding area, and even the environment.

Since the specific risks may differ from place to place, building codes may be specific to local areas, regions, or states – which is why California’s commercial building codes are different than those in Michigan or Arizona.

What classifies as a ‘commercial building’ in California?

Generally speaking, a commercial building is any structure used solely for business or profitable purposes. (Examples include office buildings, restaurants, “big box” retailers, shopping centers, warehouses, manufacturing facilities, etc.) However, California uses even broader strokes to define “commercial buildings.” According to California Civil Code CIV § 2079.13 (c), basically any property that is not a single-family home, multi-family dwelling, mobile home, RV, or vacant land is categorized as commercial by default – and is therefore subject to California’s commercial building codes.

What Building Code Does California use for Commercial Roofing Projects?

The building requirements in California for non-residential projects and buildings are laid out in the 2019 California Building Code, Title 24, Part 2 (also referred to as the “California Code of Regulations, Title 24,” “Title 24 California Building Code,” or just “Title 24” for short). The specific building codes for commercial roofing projects are contained in Chapter 15 of the California Building Code.

Title 24 Requirements for Roof Assemblies and Rooftop Structures

The California Roofing Codes includes requirements related to the following 10 aspects of roofing projects:

1. Design and installation of secondary (emergency overflow) of roof drainage systems

This relates to emergency drains, scuppers, and gutters and includes stipulations around materials to be used, considerations for preventing ponding water from becoming too deep, and guidelines for preventing water build-up in primary drains.

2. Weather protection and the design and installation of roof coverings

This section provides stipulations on the weatherproofing/waterproofing elements of the roof covering, including where flashing should be placed, the use of a corrosion-resistant metal flashing, coping dimensions, guidance on intake/exhaust ventilation for attics, and crickets and saddles for chimneys and other roof penetrations.

3. Performance requirements for different types of roofing systems

This section of the code provides comprehensive instructions for performance standards of various commercial roofing systems (including clay, tile, metal, BUR, modified bitumen, ballasted and non-ballasted roofs, etc.). Aspects covered include wind resistance standards, impact resistance, and special considerations for roofs in hurricane-prone areas.

4. Fire classification for roof assemblies

Roof assemblies are categorized for fire resistance as Class A, B, or C, according to how long they retain integrity against fire. This section specifies minimum fire resistance requirements for roofing systems in zones categorized by level of fire risk.

5. Application of roof covering materials

This brief discussion addresses requirements for applying roof covering materials, including their physical makeup, packaging requirements, and manufacturer’s installation instructions.

6. Different types of roof coverings and requirements around their application

An extensive section, which defines the standards required for all aspects of roof coverings (e.g., underlayments, roofing materials, fasteners) and how they are to be attached. Also included are instructions for clay, tile, metal, wood shake, slate, built-up roofing, etc.

7. Different types of roofing and protective coating material standards

This refers to the material standards for the protective coating of commercial roofs, including acrylic, silicone, and polyurethane coatings. It also addresses standards regarding liquid-applied roofing, vegetative roofing, photovoltaic (solar) panels, etc.

8. Material standards for roof insulations

This section identifies the standard requirements for various types of above-deck thermal insulation materials, including composite boards, cellular glass boards, extruded polystyrene, gypsum, etc.

9. Requirements for rooftop structures

This refers to the standards and requirements concerning all structures that might be built or mounted on commercial roofing systems, including penthouses, cooling towers, domes, spires, water tanks, and so on.

10. Reroofing requirements

Extensive instructions on accepted materials and application methods for recovering or replacing an existent roof structure. This section addresses acceptable structural loads, removal and replacement of old materials, roof recovering, etc.

Permits and Licenses for Roofers and Contractors

If California commercial roofing codes seem confusing and overwhelming, the penalties for failing to comply with these codes can be brutal. For that reason, it’s essential that commercial building owners and managers only hire roofers and contractors who the State of California has licensed.

These professionals go through extensive training and testing to make sure they understand state and local building codes. They know how to pull the proper local permits so your commercial roofing project can move forward without complications.

As a manufacturer representative company for the most respected roofing brands in the industry, RoofSource offers various services to ensure our customers receive quality roof installations that comply with local roofing codes. These services include helping you find the best contractors for your commercial roofing projects. To learn more about how we can help, contact RoofSource today.