As a homeowner in Oklahoma, it’s easy to overlook the complexities of residential roofing codes. Many homeowners assume that as long as their roof is functioning, they don’t need to worry about the nuances of local regulations.
If you are looking to start your roofing project, this is exactly what you should not do. Ignoring these codes can lead to costly mistakes, safety hazards, and even legal issues when repairing or replacing your roof.
Understanding Oklahoma’s residential roofing code is crucial if you want your home to meet critical safety, durability, and energy efficiency standards. Now we know what you might think: these codes are hard to understand. But don’t worry, we are here to help.
Today, we will walk you through the key aspects of Oklahoma’s residential roofing code, including the standards based on the International Residential Code (IRC) 2018 and any state-specific modifications.
IRC 2018 and Its Application in Oklahoma
Oklahoma’s residential roofing regulations are primarily based on the International Residential Code (IRC) 2018/2021. The IRC is a model building code that provides standardized regulations for the construction of one and two-family dwellings. While Oklahoma follows the IRC 2018 as a foundation, it has made specific amendments to address the state’s unique climate and environmental conditions.
Ice Barriers (Section 905.1.2)
This section states that in areas prone to ice dams, an ice barrier must be installed for certain roofing materials like asphalt shingles and metal roofs. The ice barrier must extend at least 24 inches inside the exterior wall line, and 36 inches if the slope is greater than 67%.
The Oklahoma building code follows this with modifications.
Apart from this, you need to install a 36-inch wide ice barrier in all valleys of your roof. A 36-inch wide ice barrier also needs to be installed on any change of roof slope. This means you need an ice and water shield if the lower part of the roof has a smaller slope than the upper section.
Drip Edge Exceptions
Oklahoma has also modified the IRC 2018 Section R905.2.8.5 on drip edge requirements. While drip edges are generally required at the eaves and rake edges of shingle roofs, the state allows an exception if a 1-by-2-inch shingle mold is used. In this case, as long as the starter course of shingles extends 1/4 inch to 1 inch beyond the fascia, a metal drip edge is not mandatory.
Roof Decks
The IRC 2018 Section R905.2.1 on sheathing requirements has been modified in Oklahoma. The state now defines a “solidly sheathed” roof deck as one made of sawn lumber boards or structural panels that provide a solid hold for fasteners and do not have any significant defects like gaps, warping, splitting, cracking, or rot. This ensures a sturdy foundation for properly installing asphalt shingles.
Specific Material Requirements
R905.3.1
This section of the IRC 2018 code states that clay and concrete tile should be installed over a solid sheathing or spaced structural sheathing board.
R905.4.1
Similar to the previous point, this section states that metal tile should be installed over solid sheathing or spaced structural sheathing board.
Other roof deck requirement codes:
R905.5.1 for mineral-surfaced roll roofing
R905.6.1 for slate shingles
R905.7.1 for wood shingles
R905.8.1 for wood shakes
R905.10.1 for metal roof panels
R905.16.1 for photovoltaic shingles
All of these sections of the IRC 2018 code remain the same in the Oklahoma roofing code. The only modification in the Oklahoma roofing code is the addition of a definition of a solid sheathing board, as covered above.
Roof Re-Covering Restrictions in Oklahoma
The Oklahoma residential roofing code, based on the IRC 2018, outlines specific conditions where a roof re-cover, or re-roofing, is not permitted. These requirements are designed to ensure the integrity and safety of existing roof assemblies.
The first three conditions listed in the Oklahoma code are directly aligned with the IRC 2018 requirements:
- The existing roof or roof covering is damaged or deteriorated to the point it cannot adequately support additional materials.
- The existing roof covering is made of slate, clay tiles, cement, or asbestos-cement tiles.
- The existing roof has two or more layers of any type of roof covering or material.
However, Oklahoma has added a fourth condition that is unique to the state’s code:
- The existing roof has one or more layers of asphalt shingles, additional layers of asphalt shingles are not permitted.
Moving on, let’s look at the other important aspects of the building code that you need to be aware of:
Roof Flashing (Section R903.2)
Flashing is a critical component that prevents water penetration at roof intersections, valleys, around chimneys, and other vulnerable areas. The IRC 2018 requires that flashing be made from corrosion-resistant materials and be installed in a manner that prevents water intrusion. Flashing should be installed at walls and roof intersections.
Crickets and Saddles (Section R903.2.2)
Crickets and saddles are roofing structures designed to divert water around protrusions on the roof. These structures must be installed on the ridge side of any chimney or penetration greater than 30 inches wide. They are typically constructed from the same materials as the roof, like asphalt shingles, metal, etc.
Coping (Section R903.3)
Coping refers to the covering or capping of the top of a wall to prevent water from penetrating the wall structure. The code states that coping should be done with weather-resistant, non-combustible materials.
Drains (Section R903.4)
Roofs must be sloped to allow for proper drainage. For roofs with internal drainage systems, IRC 2018 requires the installation of overflow drains or scuppers to handle excess water.
Residential Roofing Code For Asphalt Shingles (R905.2)
Though there are several other roofing materials available, asphalt shingles still remain the most popular option. Here are a few things to consider when installing a new asphalt shingle roof:
Slope (R905.2.2)
- The minimum slope for asphalt shingle application is 2:12.
- For slopes between 2:12 and 4:12, double underlayment is required to prevent water infiltration.
Underlayment (R905.2.3)
- Underlayment must be installed beneath asphalt shingles.
- For roofs with slopes of 4:12 or greater, a single underlayment is sufficient. For lower slopes (down to 2:12), two layers are required.
Asphalt Shingles (R905.2.4)
According to this section, the shingles you install must comply with ASTM D3462.
- For wind resistance, shingles must comply with ASTM D7158 or ASTM D3161.
- Asphalt shingles installed in areas with high winds (above 110 mph) must meet specific wind resistance standards.
Fasteners (R905.2.5)
Shingles must be fastened with corrosion-resistant nails such as galvanized or stainless steel. The length and placement of nails should penetrate the roofing deck by at least ¾ inch or through the thickness of the deck, whichever is less.
Make Sure Your Roof is Compliant With All The Codes!
Staying informed about Oklahoma’s residential roofing code is crucial for any homeowner. But as you know, it can be confusing as the rules are a bit complex. But don’t worry, A. Fricker Roofing and Waterproofing can help. We are licensed and insured roofers in Oklahoma with full knowledge of roofing codes and regulations. We make sure that your new roof meets all the required criteria. Contact us today at (918) 402-7167.
