Today we will be discussing Tennessee building codes as they relate to roof replacements. Building codes are a set of regulations established by the state and local authorities to ensure that buildings are safe, accessible, and structurally sound. The state of Tennessee has adopted and enforces the 2018 IRC (International Residential Code), which includes requirements for roofing systems. The codes vary depending on the location and type of building, and it is important to understand these requirements to ensure compliance and safety. Local municipalities have the authority to implement and amend the building codes as they deem appropriate, please see the below links for reference:
- Nashville, TN – Building Codes Website
- Knoxville, TN – Building Code Overview
- Franklin, TN – Building Code Information
- Williamson County, TN – Building Code Website
- Rocky Top, TN – Building Codes & Permits
- La Vergne, TN – Building Codes Website
Today we will be discussing some of the most important and common roofing codes. It is always a good idea to ensure that the homeowner has code coverage on their policy. If they do not have code coverage, there needs to be an agreement in place for how any items will be handled that are not covered by insurance. Many homeowners need to be educated on the process and that these items are required by law and that as a reputable roofing contractor you are required to include them at the time of the roof replacement.
R905.1: Manufacturers Requirements
Roofing material manufacturers create full systems that are designed to be installed together and not necessarily “mixed and matched” with other product lines. These systems are designed to be installed in a very specific process to ensure the integrity and durability of the roof. The IRC Code R905.1 requires that “Roof coverings shall be applied in accordance with the applicable code provisions and the manufacturer’s installation instructions.”
Ensuring that a roofing system is properly installed is not only a matter of building code, it will also have an effect on the validity of the manufacturers warranty.
905.2.1: Sheathing Requirements
Per this IRC Code, “Asphalt shingles shall be fastened to solidly sheathed decks”. This requires that the roofing surface be a solid surface. Roofing surfaces with large gaps, rotten wood or other damage would fall under a code requirement for the repair and replacement of the surface before the shingle roofing surface can be properly installed. This is important to note as some insurance carriers will try to categorize these issues as simply rotten wood from longterm water exposure and deny the request. This needs to be under the umbrella of CODE COVERAGE.
903.2.2: Crickets and saddles
A cricket is a small triangular shaped structure constructed on the roof slope behind a chimney. It will divert water from the above slope around the chimney and prevent water from collecting in that area. The IRC Code R903.2.2 requires, “a cricket or saddle must be installed on the ridge side of any chimney or roof penetration more than 30 inches wide as measured perpendicular to the slope.”
Without a proper roof cricket, water will collect behind a chimney on a roofing surface that isn’t meant to have standing water. This is a very common cause of roof leaks but completely preventable by a properly installed chimney cricket.
R905.2.8.2: Valley Lining Code
When two roofing slopes meet in a downward angle, it creates a roof valley where water will collect and flow. Per code 905.2.8.2, “valley linings shall be installed in accordance with the manufacturer’s installation instructions before applying shingles.”
For open valleys, where the lining is visible, it should be metal or a mineral surfaced roll roofing. For closed valleys (valley is underneath the installed shingles), there should be underlayment or ice and water shield.
R905.2.8.5: Drip Edge
Drip edge is a metal flashing that is installed on the rakes and eaves of the roof to protect fascia and other roofing components from flowing water. It is one of the most important items to be installed on the roof. Per IRC Code R905.2.8.5, “a drip edge shall be provided at eaves and gables of shingle roofs. Adjacent pieces of drip edge shall be overlapped a minimum of 2 inches. Drip edge shall extend a minimum of a ¼ of an inch below roof decking and extend up a minimum of 2 inches. Underlayment must be installed over the drip edge along the eaves and under the underlayment on gables.” When properly installed, drip edge will protect fascia and roof decking from water damage.
R908.5: Existing Flashings
IRC Code R908.5 Requires that any existing flashings be replaced if damaged or deteriorated. The roof removal and replacement process typically leaves most flashings, vents and accessories damaged by previous nail holes and the force required to tear them off. Chimney flashing is typically installed in an interwoven pattern with the shingle material and it is improper to reuse flashings with existing holes and damage. This code requires that these materials be replaced with new undamaged and durable materials to ensure the integrity of the roof against rain and weather elements.
If you are a roofing contractor in Tennessee and you need help with supplementing, please visit our Roof Supplementing page for more information or schedule a time below to speak with our Founder/CEO. We offer a range of roof supplementing and estimating services utilizing both Xactimate and Corelogic Symbility.