When investing in a new roof in Nashville, you’re expecting it to be installed correctly. Part of installing a roof the right way is adhering to Tennessee building codes.
Unfortunately, some Nashville roofing contractors don’t follow rules or they leave certain things required by codes off your estimate to lower their prices. This could cause your home to fail an inspection, lead to roof leaks, and can even shorten your roof’s lifespan.
Here at Bill Ragan Roofing, we want every homeowner to have the knowledge they need about their upcoming roof replacement. That’s why we’re going to give you the 8 roofing codes you need to know.
Keep in mind, this is based on the 2018 International Residential Code. There are a lot more than 8 roofing codes, but these are the ones we think homeowners need to know about to get the most out of their roof investment.
By the end of this article, you’ll know 8 roofing codes in Nashville, Tennessee, homeowners need to know before their roof replacement. And at the very end, don’t forget to grab your free checklist to hire a great roofing contractor to ensure you get a roof that's up to code.
1. Crickets and saddles (R903.2.2)
A roof cricket is a double triangle structure built behind a chimney to properly divert water around it. According to code R903.2.2: 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.
The cricket or saddle coverings also shall be sheet metal or of the same roofing material as the roofing covering. This code ensures water coming down your roof has a way to get around a wide chimney or roof penetration.
Without a roof cricket, water pools behind your chimney on a surface that isn’t meant to have sitting water. This will ultimately lead to a leak and could be costly to repair the damage.
2. Roof covering application (R905.1)
Every shingle manufacturer has specific installation instructions your roofing contractor needs to follow to ensure your roof is properly installed. According to code R905.1: roof coverings (roofing materials) shall be applied in accordance with applicable provisions of this section and the manufacturer’s installation instructions.
This code means your local roofing contractor must follow all the installation instructions provided by the shingle manufacturer. Not only is this a building code, but it also determines if your material warranty will be honored.
If your roofing materials aren’t installed properly, your roof isn’t up to code and it’ll void the roofing material warranty you get from the manufacturer.
This code means that your roof decking (roof sheathing) must be able to withstand and hold your new roof when it’s installed. If there’s any rotten decking or if the decking can’t handle the new roofing materials, it must be replaced before your roof is installed.
Be aware, some roofing contractors lower their prices by skipping this to undercut the competition. When meeting with your roofing contractor, always ask them (if they haven’t done it already) to check your roof decking’s integrity.
4. Slope (R905.2.2)
The slope (or pitch) of your roof is the steepness calculated by the number of inches or feet it rises vertically for every 12 inches or feet it extends horizontally. For example, a roof that has a 4/12 pitch will be 4 inches (or feet) up for every 12 inches (feet) out.
According to code R905.2.2: asphalt shingles shall be used only on roof slopes of 2 units vertical in 12 units horizontal (2:12) or greater. For roof slopes from 2:12 up to 4:12, double underlayment is required.
This code means that if a roof has a pitch (slope) below 2:12, it’s not steep enough, per the shingle manufacturers or codes, to put shingles on it. If your roof’s slope is below a 2:12 pitch, it’s considered low slope and requires a membrane or metal roof system.
5. Ice barrier (R905.2.7.1)
Ice damming is when snow and ice freeze down by your gutter line (eaves), creating an ice blockage (dam). When it happens at your gutters, the thawed snow/ice will back up until the water gets underneath your roofing materials.
This causes water to come through your ceiling and even down your wall. As ice damming becomes more common in Tennessee, codes are now in place to prevent roof leaks when we have a snow or ice storm.
According to code R905.2.7.1: in areas where there has been a history of ice forming along the eaves causing a backup of water, an ice barrier that consists of of at least 2 layers of underlayment cemented together or self-adhering polymer modified bitumen sheet (ice and water shield) that extends from the lowest edges of all roof surfaces to a point at least 24 inches inside the exterior wall line of the building.
This code means that if your roof has a history of ice damming, it needs a protective layer (ice and water shield) around the edges of your roof that goes 2 feet past the interior walls of your home. This code can only be applied when your old roof is torn off, and you’re starting from a clean deck.
6. Roof valleys (R905.2.8.2)
A roof valley is when two slopes of a roof meet. A roof valley is crucial to keep water flowing down your roof properly.
According to code 905.2.8.2: valley linings shall be installed in accordance with the manufacturer's installation instructions before applying shingles. Just like the roof covering application, this code means that the proper linings (per manufacturer installation instructions) have to be installed in your roof valleys before installing shingles.
For open valleys (you can see the lining), it should be metal or a mineral surfaced roll roofing.
For closed valleys (valley is covered with shingles), there should be underlayment or ice and water shield.
7. Drip edge (R905.2.8.5)
Drip edge is the metal flashing that’s installed at the edges of the roof to help control the flow of water away from your fascia and other roofing components. It’s not only a crucial roofing component, but it’s also one of the first things a home inspector looks for on a roof.
According to 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.
This code means that drip edge must be installed (in accordance with the above specifications) on the edges of your roof. Properly installed drip edge ensures water won’t get behind your gutters and rot out your fascia board or your roof’s decking.
Unfortunately, some roofing contractors cut corners by leaving off drip edge. When this happens, your roof won’t be up to code, and it’s going to be a lot harder to pass a home inspection.
8. Reinstallation of roofing materials (R908.5)
When your roof is replaced, certain roofing materials might not need to be replaced. As long as the roofing material’s (roof flashing, roof vents, etc.) integrity and functionality aren’t affected, they can be reinstalled on your roof.
However, according to code R908.5: existing slate, clay, or cement tile shall be permitted for reinstallation, except when damaged, cracked, or broken. Any existing flashings, edges, outlets, roof vents, or similar devices that are part of the assembly must be replaced when rusted, damaged, or deteriorated.
This code means that if any of your outer roofing materials or components are damaged or if they lose functionality, they have to be replaced during your roof replacement. This is especially important if you have a code upgrade policy or if your insurance claim needs to be supplemented.
If any of your roof vents or roof flashing are damaged by hail (or other storm-related damage), your insurance company will pay (depending on your policy) to replace them in accordance with this code.
Hire a great roofing contractor to ensure your roof is up to code
You just learned 8 roofing codes you need to know in Nashville, Tennessee. Remember, this is just a taste of the building codes set forth by the 2018 IRC.
Like I stated a couple of times in this article, some roofing contractors don’t follow these codes to bring their prices down. Whether it’s to beat out the competition’s prices or they’re just lazy, a lot of homeowners have been taken advantage of by these practices.
Because of this, it’s crucial to know how to spot a great roofing contractor from one that might not have your best interest in mind. To do this, you have to ask the right questions and get the right answers back when meeting (or talking) to potential roofing companies.
That’s why you need this checklist. Your free checklist has the 16 questions every homeowner needs to ask a potential roofing contractor to ensure they do things the right way.
Don’t get taken advantage of during a stressful time; keep going to get your free Checklist of Questions to Ask a Roofing Contractor.
Since 1990, the team at Bill Ragan Roofing has proudly helped homeowners in Nashville and surrounding areas with their roofing needs. Whether you need repairs or a roof replacement, you can count on us to do things the right way. That’s why we’re more than happy to provide you with a lifetime warranty on our workmanship.