Charleston’s ground snow load sits at 20 pounds per square foot, but that number never touches your rafters directly. The code trims it to roughly 14 psf for an ordinary sloped roof, then adds weight back wherever snow drifts against a wall or a dormer. Start by pulling the ground snow load and wind speed figures your county building department uses for permits, since elevation and local adoption both shift the number away from the reading at the reference city.
What is the ground snow load in West Virginia?
The design ground snow load at Charleston is 20 pounds per square foot (psf), mapped under ASCE 7-16 at the point closest to the city, elevation 746 feet. That is the figure a permit application, a plan review and the truss drawings a builder orders all trace back to. It is not, however, the load a roof is designed to carry. It is the load measured on open ground, before the code applies exposure, thermal and slope factors that reduce it once it reaches a sloped, heated house roof.
From ground load to roof load
For an ordinary heated sloped roof, that conversion lands the working number near 14 psf, the value a truss engineer actually designs to at this location. A steeper roof pulls the number down further, since snow sheds off pitch faster than it does off a low slope. None of this changes on a flat commercial roof, where the reduction is smaller and the exposure factors work differently, which is one more reason the ground figure alone tells an incomplete story.
ASCE 7-22, an edition a handful of jurisdictions are beginning to look at, maps the same point at 39 psf. That is not more snow falling on Charleston and it is not a sign that existing roofs are suddenly undersized. The newer edition reports a strength-level number built on a 1.0 load factor, while the 7-16 figure above is a nominal number built on a 1.6 load factor. They describe the same physical snow load two different ways, and IRC/IBC 2021, the edition that makes ASCE 7-16 the applicable one in most states, is what governs the permit a reader is likely holding today. Ground snow load varies with elevation, so a figure pulled from this reference city says nothing reliable about a roof at a few thousand feet more elevation. Whether a given roof was built to the right number is a question for the local building department or a licensed engineer, not something this figure settles on its own.
How much snow can a roof hold in West Virginia?
There is no single number for this, and any answer that gives you one inch figure is guessing. What decides the outcome is the combination of the roof’s own design load, the weight of what actually accumulated, and where it piled up.
Drift is the real hazard
Starting from the roughly 14 psf figure a sloped roof near Charleston is designed to, a steep roof sees less because snow slides off before it builds up, and a low-slope or flat section sees closer to the full converted value. The real danger sits at the parts of a roof the flat conversion does not describe well: against a taller adjoining wall, below a dormer, in a valley where two roof planes meet, or on a lower roof next to a taller one that sheds onto it. Drift can stack snow in a narrow band, and that is where overloaded roofs actually fail, not across the open field of the roof. A state with wide-open, wind-scoured terrain like Nebraska sees a very different drift pattern than West Virginia’s hollows and ridgelines, where terrain and nearby trees break up the wind instead of concentrating it evenly.
Weight, not depth, is what matters, and the two are not the same number twice in one winter. A layer of ice on top of either adds more weight again in a much thinner layer. That is why a foot of snow sitting since January, compacted and partly refrozen, can outweigh a foot that fell fresh last week, and why nobody can honestly tell you how many inches a roof can take without knowing what that snow has become.
Watch for the signs that a roof is carrying more than it should, rather than trying to estimate weight from the ground:
- Interior doors that suddenly stick or won’t latch
- New cracks in ceiling drywall or at wall-ceiling joints
- A ridge line that looks like it’s sagging when viewed from the yard
- Creaking or popping sounds from the attic under load
Raking snow off from the ground with a roof rake, working from the eaves, is the safe response to a heavy accumulation. Climbing onto a loaded roof to shovel it is not, both because of the fall risk and because concentrated foot traffic adds load exactly where the structure is already stressed.
What wind speed must a roof withstand in West Virginia?
The basic design wind speed at Charleston is 107 mph under ASCE 7-16, for Risk Category II, the category that covers ordinary houses. That number is a 3-second gust measured at 33 feet in open (Exposure C) terrain, not a sustained wind and not the kind of figure a weather forecast reports. Compare it to a hurricane’s headline sustained wind speed and the code will look weak by comparison, but the two are measuring different things entirely, and the gust figure is what actually drives structural design.
What the gust speed governs
ASCE 7-22 maps the same point at 107 mph too, so this is one of the rare figures where the newer edition doesn’t move the number at all, even though it’s still the 7-16 edition that IRC/IBC 2021 makes applicable in most jurisdictions today.
That design speed sets the shingle wind rating a roof needs, the nailing pattern the shingles are installed with, how the sheathing is fastened to the rafters or trusses, and the strength of the uplift connections tying the roof structure down to the walls. Roofs fail at their edges first, not in the middle of a plane. Eaves, rakes and ridges are where wind uplift concentrates, which is why proper edge nailing and starter-strip detail matter more at those lines than anywhere else on the field of the roof. Where the wind-borne debris flag applies, the code adds a requirement for impact-rated glazing or shutters on top of the base wind design. Neighboring Kentucky maps at a different basic wind speed at its own reference city, which is one more reason a figure quoted for Charleston should never be assumed to apply statewide, let alone across a state line. Whether a specific roof assembly meets the design speed for its address is something the local building department or a licensed engineer confirms, not something a mapped figure answers by itself.
Does West Virginia require an ice barrier under the shingles?
An ice barrier is a self-adhering membrane installed along the eaves, run up far enough to pass the interior wall line below. Its job is narrow: stop water from an ice dam from working its way under the shingles and into the roof deck. It does nothing to stop snow from accumulating and nothing to stop a dam from forming in the first place.
What actually causes an ice dam
Ice dams form when heat escaping from the living space into the attic warms the underside of the roof deck enough to melt the snow sitting on it. That meltwater runs down under the snow layer until it reaches the cold overhang past the exterior wall, where there’s no warm attic underneath, and refreezes there. The ice builds up into a dam, and water backs up behind it, under the shingles, looking for anywhere to go. NOAA’s 1991-2020 climate normals put Charleston’s coldest month mean minimum at 26.1°F, cold enough, combined with an ordinary winter’s snow load, for that freeze-thaw cycle at the eave to be a real and recurring risk rather than a rare event. The membrane protects the deck once a dam has formed. It does not stop one from forming. Only air sealing the attic floor and adding enough insulation to keep the roof deck close to outdoor temperature actually prevents the dam, and West Virginia’s 55 counties split between IECC climate zone 4A (36 counties) and zone 5A (19 counties), which is the split that sets how much attic insulation a given county’s energy code table calls for. A reader who installs the membrane and stops there has protected against the symptom, not the cause.
West Virginia’s own residential code is the West Virginia State Building Code (87 CSR 4), based on the 2018 edition of the International Residential Code and administered by the West Virginia State Fire Marshal. Adoption, though, is left to each county or city. Where a jurisdiction has adopted the state code, it governs and any earlier local code falls away; where none has, there may be no residential code addressing eave protection at all. As of the most recent check, no update to the 2021 IRC had been adopted at the state level. Whether an ice barrier is required at a specific address, and how far up the roof it must run, is a question for the local building department, since the answer depends entirely on what that jurisdiction has adopted.
What roofing material suits West Virginia best?
The honest answer starts from the loads already covered here, not from a general preference for one material over another. At Charleston’s roughly 14 psf converted roof snow load and 107 mph basic design wind speed, the choice between materials changes what a roof does with that load, not whether it has to carry one at all.
Comparing the options
| Material | Snow behavior | Wind consideration | Added dead weight |
|---|---|---|---|
| Architectural asphalt shingles | Holds snow on the surface longer, spreading the load | Wind rating depends on nailing pattern actually used | Lightest of the common options |
| Standing-seam metal | Sheds snow and ice in sheets, which must land somewhere safe | Panel attachment and clip spacing govern uplift resistance | Comparable to shingles, varies by gauge |
| Slate or concrete tile | Holds snow well, similar to shingles | Fastening detail is critical at edges and ridges | Substantially heavier, adds to the structural load itself |
Standing-seam metal sheds snow and ice cleanly, which is an advantage on the roof itself and a hazard everywhere the shed snow lands. Deciding where that slide discharges, over a doorway, a walk, a driveway or a parked car, is a design decision made before installation, not something to discover the first time it happens. Slate and concrete tile carry their own dead weight in addition to whatever snow sits on top, so that weight has to be accounted for in the structural design from the start, not treated as incidental. Whatever material is chosen, the fastening schedule and the underlayment detail matter more than the material rating on the box. A shingle rated for a high wind speed, nailed to a lower standard than its own installation instructions call for, performs to the lower standard in an actual storm. Before settling on a covering, it’s worth reviewing sound roofing practice on deck preparation and flashing, since those details decide how well any of these materials actually perform once they’re loaded with wind or snow. None of this substitutes for a local building department’s review of a specific project, which remains the only place to confirm what a given roof actually needs to meet.