Ice that backs up under Georgia shingles during a rare hard freeze does more damage than the snow itself ever does, soaking attic Insulation and staining ceilings for weeks after the storm clears. Atlanta’s design ground snow load is only 5 psf, one of the lowest figures anywhere on the national map, and that low number is exactly why so many Georgia roofs get built with none of the snow detailing a heavier-snow state can’t skip. Check whether your county requires an ice barrier membrane at the eaves before a re-roof goes on, because that’s the one line item in Georgia’s own code where the rules actually bite.
What is the ground snow load in Georgia?
The design ground snow load at Atlanta is 5 psf under ASCE 7-16, the edition IRC/IBC 2021 makes applicable in most states. That figure describes the load sitting on open, level ground in a snowstorm. It is not the load a roof carries: the code runs it through exposure, thermal and slope factors before it ever reaches a rafter, and for an ordinary heated sloped house roof in Atlanta the converted number works out to roughly 4 psf of roof snow load. Confusing the two is the single most common mistake anyone makes with this figure, and it matters because the roof number, not the ground number, is what a framing package is actually sized to.
This is also the number that does real work before a shovel ever touches the site. A permit application cites it, a plan reviewer checks the truss calculations against it, and the manufacturer who stamps the truss drawings builds it into the design load before the lumber gets cut. For most of Georgia, 5 psf is a small enough number that snow load rarely drives a roof design at all. Wind and dead load usually govern instead, which is worth knowing before you start a roofing project and wonder why the truss engineer barely mentions snow.
Two code editions, two different bases
A newer edition, ASCE 7-22, maps the same point at 19 psf, but that number cannot be compared directly to the 5 psf figure above. ASCE 7-16 is a nominal value used with a 1.6 load factor. ASCE 7-22 is a strength-level value used with a 1.0 load factor. The jump from 5 to 19 is not more snow falling on Atlanta and it is not evidence that a house built to the older number is undersized. It is the same measurement expressed on a different scale, and a few jurisdictions are only beginning to adopt the newer edition. The number on your permit today is the 7-16 figure.
North Georgia’s mountains are treated differently again. That ground falls inside what the map calls a case study region, meaning the national map assigns it no value at all. A site-specific snow study, tied to actual elevation, is required there before a truss package can be engineered. Anyone building above the foothills should ask their building department for that study rather than borrowing Atlanta’s flatland number, because elevation changes the load by a wide margin over a short distance.
How much snow can a roof hold in Georgia?
There’s no single number that answers this question, and any answer that gives one inches figure is guessing. What a roof actually carries depends on the roof’s slope, on how exposed it is, and on where snow has been pushed by wind rather than left where it fell.
Start from the Atlanta ground figure of 5 psf. The code converts that to roughly 4 psf on an ordinary heated sloped roof, and a steep roof carries less still, because snow slides off before it can pile up. A flat or low-slope roof carries closer to the full converted value, since nothing helps the snow leave. That difference between roof pitches is built into the same conversion that turns the ground number into a roof number in the first place.
Drift is where roofs actually fail
Drift changes the picture completely. Snow pushed by wind against a taller wall, piled below a dormer, or trapped in a roof valley can run several times deeper than snow lying on an open, unobstructed slope. A lower roof section next to a taller one is a classic drift trap: the taller roof sheds snow onto the lower one, and that load has nothing to do with the flat 5 psf ground figure at all. This is where most snow-related roof failures actually happen, not on the open field of a plain gable.
What the snow has become matters as much as how deep it is. Fresh, light snow runs roughly 5 to 7 pounds per square foot for every foot of depth. Settled snow, or snow that has partly melted and refrozen, runs two to three times heavier for the same depth. A layer of ice on top of either adds more weight again, in a much thinner layer. That’s why a foot of snow that fell in March, wet and heavy, can load a roof far harder than a foot of dry January snow, even though a tape measure reads the same number both times.
Watch for the practical signs that a roof is being asked to carry more than it should:
- Interior doors that suddenly stick or won’t latch
- New cracks in ceiling drywall, especially near the center of a span
- A ridge line that looks like it’s sagging when viewed from the street
- Popping or cracking sounds from the attic during or after a heavy snow
If you see any of those, raking accumulated snow off the roof edge from the ground, with a long-handled roof rake, is the safe response. Climbing onto a snow-loaded roof to shovel it is not, and it’s how most snow-related roof injuries happen. For a design question rather than an emergency, the local building department or a licensed engineer can tell you what a specific roof was built to carry. This page gives the design figure. It can’t tell you whether any one roof is adequate.
What wind speed must a roof withstand in Georgia?
The basic design wind speed at Atlanta is 107 mph under ASCE 7-16, and that number needs its basis stated plainly or it gets misread. It is a 3-second gust measured at 33 feet in open, Exposure C terrain, for Risk Category II, the category ordinary houses fall into. It is not a sustained wind, not a record gust, and not the number a weather forecast calls “wind speed.” Comparing it directly to a hurricane’s headline gust speed will make the code look far weaker than it is, when really it’s a different kind of measurement entirely.
ASCE 7-22, the coming edition, maps the same point at 105 mph. That’s close enough to the 7-16 figure that it isn’t worth reading anything into the small drop. The number that governs a Georgia permit today is still the 107 mph 7-16 figure.
What the number buys on the roof
This figure drives the shingle wind rating a roofer specifies, the nailing pattern used to attach that shingle, how the sheathing is fastened to the rafters or trusses, and the uplift connections, straps and clips, that tie the roof structure down to the walls. Roof edges, rakes and ridges take the worst of it, because wind pressure concentrates at those transitions rather than spreading evenly across a plain field of shingles. That’s where a poorly fastened roof starts to fail first, and it’s the detail a wind-resistant shingle rating alone can’t fix if the fastening underneath doesn’t match it.
Georgia’s Atlantic coast sits on the same wind map, and design speeds there run higher than the Atlanta figure inland, similar to how South Carolina’s coast runs well above its own inland cities: see the South Carolina’s roof snow load and wind rules for a coastal comparison. Coastal counties may also fall inside a wind-borne debris region, which brings a real, specific obligation: impact-rated glazing or approved shutters on exposed openings. Whether that flag applies to a given address, and which edition currently governs it locally, is a question for the county building department, not a number to guess at from an inland reference point.
Does Georgia require an ice barrier under the shingles?
An ice barrier is a self-adhering membrane installed under the shingles, run from the roof edge up past the interior line of the exterior wall. It isn’t there to stop snow from sitting on the roof. It’s there to stop meltwater, backed up behind an ice dam at the eave, from working its way under the shingles and into the roof deck below.
What actually causes an ice dam
An ice dam forms when heat escaping from the living space into the attic warms the roof deck enough to melt the snow sitting on it. That meltwater runs down the roof until it reaches the cold overhang past the exterior wall, where there’s no warm attic underneath, and it refreezes there. Snow keeps melting from above and pooling behind that ice ridge until it finds a way under the shingles. The membrane protects the deck once that happens, but it does nothing to stop the dam from forming in the first place. Only air sealing and attic insulation address the actual cause, and a reader who installs the membrane and stops there has bought protection against the symptom, not the problem.
Georgia’s own residential rules are the Georgia State Minimum Standard One- and Two-Family Dwelling Code, based on the 2024 edition of the International Residential Code, in force statewide since January 1, 2026 and administered by the Georgia Department of Community Affairs. It sets a statewide minimum that a city or county may exceed, but the state amendment packet makes no change to how the model code treats ice barriers, which are triggered by a documented history of ice damming at the eave.
That history is exactly what Georgia’s climate mostly doesn’t build. Atlanta’s coldest-month mean minimum temperature runs 35.6°F under NOAA’s 1991-2020 climate normals, above freezing on average even in the depth of winter, and the ground snow load at the same reference point is only 5 psf. Together, those numbers describe a climate where sustained hard freezes and repeated snow-melt-refreeze cycles, the pattern that actually builds an ice dam, are uncommon across most of the state. North Georgia’s higher, colder mountain counties are the exception, and a county there may reasonably see the requirement enforced, or a builder may choose to run the membrane anyway as cheap insurance on a re-roof.
Compare that to a colder state: ice barrier enforcement is a routine, unremarkable line item almost everywhere in Ohio’s roof snow load and wind rules, because Ohio’s winters build the ice-damming history that most of Georgia simply doesn’t have. Confirm the actual requirement for your address with the local building department before a re-roof goes out to bid, since a municipality is free to require more than the state minimum even where the model code and the state amendment packet stay silent.
What roofing material suits Georgia best?
Georgia’s numbers point toward wind performance as the deciding factor, not snow. With a ground snow load of only 5 psf at Atlanta and a basic design wind speed of 107 mph, most of the state is a low-snow, moderate-wind design problem rather than the reverse. The state also spans two IECC climate zones, zone 3A across 118 counties and zone 2A across 41 counties, under the 2021 IECC county table. Check that table or the ENERGY STAR map for your own county rather than assuming one zone covers the state.
What each option actually changes
Architectural asphalt shingles are rated for wind performance by class, and that rating only holds if the nailing pattern matches what the rating assumes. A high-wind-rated shingle nailed to a standard pattern performs like a standard shingle, not like the rating on the wrapper. Standing-seam metal sheds snow cleanly, which is an advantage on the roof itself but a design decision everywhere the snow lands next: over a walkway, a doorway or a driveway, sliding snow and ice needs somewhere safe to go, and that has to be planned into the layout rather than discovered after the first slide. Slate and concrete tile carry meaningful weight of their own, and that dead load stacks on top of whatever snow load the roof structure already carries, so a structure has to be sized for the tile as well as for the snow.
| Material | Wind performance | Snow behavior | Added dead weight |
|---|---|---|---|
| Architectural asphalt shingles | Rated by class, depends on matching nailing pattern | Holds snow in place rather than shedding it | Low |
| Standing-seam metal | Strong when properly clipped and fastened | Sheds snow and ice quickly, sometimes all at once | Low |
| Slate or concrete tile | Heavy, generally wind-resistant when properly fastened | Holds snow similarly to shingles | High, adds to structural load |
None of these is simply “best” without saying what it’s best at. A roof in a wind-exposed spot benefits most from correct fastening and underlayment, whatever the surface material ends up being. A roof over a walked path benefits most from a covering that doesn’t dump snow onto the path below. The building department reviewing the permit, not this page, is where a specific structure gets checked against Georgia’s design figures.