Georgia Roof Guide

What is the ideal pitch for a roof?

Short answer. For an asphalt shingle roof, a pitch between about 4/12 and 9/12 is close to ideal: it drains well, meets shingle requirements without extra underlayment, and is still walkable enough to keep labor costs reasonable. Steeper pitches look dramatic and add attic space but cost more to build and roof.

There is no single ideal pitch. It depends on what you want the roof to do.

For water shedding

Steeper roofs drain faster and keep debris moving. Below 4/12, shingles need double underlayment, and below 2/12, shingles are not allowed at all and a membrane or low slope metal is required. Under Georgia's heavy summer downpours, 4/12 and up keeps water moving.

For cost

Roofs up to about 6/12 or 7/12 can be walked. Beyond that, crews need roof jacks, harnesses and more time, so steep slope charges appear on estimates. A steeper roof also has more surface area: a 12/12 roof has about 41 percent more area than its footprint, versus about 12 percent for 6/12.

For attic space and looks

Steeper pitches create usable attic or bonus room space and a more traditional look. Low pitches suit ranch and modern styles.

For solar

A common rule of thumb is that panels produce best when tilted near your latitude. Metro Atlanta sits near 34 degrees north, so roofs around 6/12 (26.6 degrees) to 8/12 (33.7 degrees) are close, and solar output is fairly forgiving either way. See replacing your roof before solar.

For wind

Hip roofs of moderate pitch tend to perform well in wind compared with tall, flat gable ends. See wind damage to roofs in Georgia.

In depth

OSB or plywood roof decking: which is better, and what happens at a reroof?OSB vs plywood roof decking in Georgia: span ratings and thickness, how each fails when wet, plank decks, and What is drip edge, and does a Georgia roof need it?What roof drip edge does, what IRC R905.2.8.5 requires in Georgia, how it should lap with underlayment, and hoArchitectural or 3-tab shingles: which is right for a Georgia home?Architectural vs 3-tab shingles in Georgia: weight, wind warranties, lifespan, availability as 3-tab lines shr

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