Roofing code greeneville, tn
Doing a roof replacement inside the city limits of Greeneville Tennessee? Did you know that you are required to pull a permit w/ the town of Greeneville? Greeneville (within city limits) does require a permit and mid roof inspection. Inspectors require a 24 hr notice for the mid roof inspection. The town of Greeneville has adopted the 2018 IRC for their guidelines. Finding much information online about the roofing code requires may prove difficult if you don’t know what is written in the 2018 IRC (international residential code) book.
Here is a list of roofing code requirements when installing asphalt shingles on your roof.
How many layers of roofing can be installed on the house? (2) if you have a primary shingle roof. However proper installation of underlayment is still required and will be inspected during the mid roof inspection.
Can you install metal roofing over 1 layer of shingles? Yes. Again be sure to follow proper underlayment installation.
NOTE: Although it is permitted to install a 2nd layer of roofing over the 1st layer, it is not best practice. Best practice always dictates to remove all layers of roofing materials (underlayment included) in order to perform a deck inspection.
Deck inspection: A proper deck inspection will help to see an area of the roof that may have soft decking due to old leaks and replace that decking. Additionally, spaced plank decking can then easily be identified.
Spaced plank decking: 2018 IRC states that shingle roofs must be installed on a solidly sheathed deck. A solidly sheathed deck is decking that has spaces that do not exceed 1/4” between the planks. If there are larger than 1/4” spaces throughout the roof, as with most spaced plank decking, the likelihood of missing the decking while nailing is high. This causing wind lift and potential for leaks. All shingle manufacturers also require the shingles to be installed on a solidly sheathed substrate. 2018 IRC 905.2.1
Underlayment: All underlayment must comply with ASTM D 226, D1970, D4869, and D6757 and is to be a label indicating compliance to the standard designation.
For roof slopes 4/12 and greater: Underlayment shall be one layer applied in the following manner; installed in shingle fashion, parallel to and starting from the eave and lapped 2 inches. Distortions in the underlayment shall not interfere with the ability of the shingles to seal. End laps shall be 4 inches and shall be offset by 6 feet.
For roof slopes between 2/12 and 4/12 pitch: Underlayment shall be 2 layers applied in the following manner; apply a 19 inch strip of underlayment felt parallel to and starting at the eaves. Starting at the eave apply 36 inch wide sheets of underlayment, overlapping successive sheets 19 inches. Distortions in underlayment shall not interfere with the shingles ability to seal. End laps shall be 4 inches and offset by 6 feet. Laymen’s terms: Double layer of felt installed w/ half lap pattern. 2018 IRC 905.2.2
Exceptions for underlayment: As an alternative, self-adhering polymer-modified bitumen underlayment complying with ASTM D 1970 installed in accordance with both the underlayment manufacturer's and roof covering manufacturer’s instructions… shall be permitted. Layman’s terms: Ice and water shield barrier membrane.
For roof slopes less than 2/12 pitch: Shingles are not permitted to be installed
Valley liner: For open valleys, a metal 24'“ wide liner of two layers of mineral surfaced roll roofing (18” bottom layer and 36” top layer) is permitted.
For closed valleys, you can use either of the 2 open valley methods, or one layer of 36” wide smooth surface mineral roll roofing, or ice and water shield barrier.
Chimneys do not require a cricket unless the width of the chimney on the upslope of the roof is more than 30” wide.
Drip edge flashing: Must be installed at both the rakes and eaves of the shingle roof.
Please note: This blog is meant as a guide and you should always confirm and check w/ local building inspectors for all details relating to your building project.
