Newark’s design ground snow load is 25 pounds per square foot, and that’s the figure a New Jersey building permit is built on. Once the code applies its exposure, thermal and slope factors for an ordinary heated house roof, that ground number lands closer to 18 psf, the value that actually reaches the rafters. If you’re pulling a permit or ordering truss drawings, it’s the converted figure a plan reviewer checks, not the raw ground number. Confirm both with your local building department, since elevation and distance from the coast shift them across the state.
What is the ground snow load in New Jersey?
Ground load vs. roof load
Newark’s mapped ground snow load is 25 psf under ASCE 7-16, the edition IRC/IBC 2021 makes applicable in most states. That’s the load spread across open, level ground, not the load sitting on a rafter. The code takes that ground number and runs it through exposure, thermal and slope factors before it becomes a design value for a specific roof. For an ordinary heated house with a sloped roof, that arithmetic brings the number down to roughly 18 psf. A flatter roof, a shaded site or an unheated space can push it back up, and a steep roof shedding snow readily can push it lower still.
This is the figure that shows up on a permit application, that a plan reviewer checks a truss package against, and that a builder hands to a lumberyard when ordering engineered rafters or trusses. It’s not decoration. A truss drawing stamped for a lower load than the site requires is a real defect, and the only people qualified to say whether a specific roof meets it are the local building department or a licensed engineer, not a homeowner reading a map.
Two code editions, not two snowfalls
A newer edition, ASCE 7-22, maps the same point at 45 psf. That is not more snow falling on Newark and it is not a sign that existing roofs were built undersized. The two figures sit on different bases: ASCE 7-16 is a nominal value used with a 1.6 load factor, while ASCE 7-22 is a strength-level value used with a 1.0 load factor. A few jurisdictions are beginning to adopt the newer edition, but the number that governs a New Jersey permit today is the 7-16 figure.
Both figures belong to Newark specifically. Snow load climbs with elevation and shifts with distance from the coast, so a site on higher ground elsewhere in the state can carry a different mapped value entirely. New York’s Adirondack elevations, for comparison, produce a very different picture, covered in our guide to New York’s roof snow load and wind rules. If your address isn’t Newark, treat this figure as a starting point and ask your building department for the number that applies to your site.
How much snow can a roof hold in New Jersey?
There’s no single answer to that question, because it depends on the roof’s shape, its exposure, and what the snow on it has become, not just how many inches fell overnight.
Where drift changes everything
Start from Newark’s roof value, roughly 18 psf for an ordinary heated sloped roof once ASCE 7-16 factors are applied. That number assumes snow spread evenly. Real roofs rarely see it that way. Snow drifts against a parapet or a taller adjacent wall, piles up below a dormer, collects in a valley where two roof planes meet, and stacks deepest on a lower roof sitting beside a taller section of the same house. Those drift zones can carry several times the uniform design value in a single spot, and drift is where roofs actually fail, not across the open field of a simple gable.
Turning depth into weight
Depth alone tells you very little, because snow’s weight changes with what it’s made of. Fresh, light snow runs roughly 5 to 7 pounds per square foot for every foot of depth. Settled or wet snow runs two to three times that for the same depth, and an ice layer on top adds more weight again in a much thinner slab. That’s why a foot of powder in January and a foot of wet, heavy snow in March are not the same load, even though a tape measure reads the same number both times.
| Snow condition | Approximate weight per square foot, per foot of depth |
|---|---|
| Fresh, light snow | 5 to 7 lb |
| Settled or wet, heavy snow | Two to three times fresh snow |
| Ice layer on top | Heavier again, in a much thinner layer |
Signs a roof is asking for too much
Watch for practical warning signs rather than trying to estimate a load from the ground:
- Interior doors that suddenly stick or won’t latch
- New cracks appearing 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 framing under a heavy load
If you see any of those, the safe response is to rake accessible snow from the ground with a roof rake, working from the eave and taking off manageable sections rather than one huge slab at once. Climbing onto a snow-loaded roof to shovel it is not the safe response. It adds your own weight to a structure that may already be near its limit, on a surface that is, by definition, slick.
What wind speed must a roof withstand in New Jersey?
What the gust figure actually measures
Newark’s basic design wind speed is 115 mph under ASCE 7-16, for Risk Category II, an ordinary house. That’s a 3-second gust measured at 33 feet in open, flat terrain, not a sustained wind speed and not the headline number a news report gives for a storm’s top speed. Comparing it directly to a hurricane’s reported wind speed will make the code look weak when it isn’t measuring the same thing at all. ASCE 7-22 maps this same point at 115 mph too, so unlike the snow figure, the wind number for Newark doesn’t shift between editions.
Newark is the inland reference point for this figure. New Jersey’s coastline carries a materially higher design speed and its own wind-borne debris region requirements, which is a real, costly obligation where it applies: impact-rated glazing or approved shutters on new construction. A reader near the shore should not assume the inland figure covers their address, and should check the exact design speed and any debris-region flag with their local building department before ordering windows or shutters. Alabama’s Gulf coast counties show how far that gap can run, laid out in our guide to Alabama’s roof snow load and wind rules.
Where uplift concentrates
The wind speed figure governs the shingle wind rating a roofer selects, the nailing pattern used to install it, how the sheathing is fastened to the rafters, and the uplift connections tying the roof structure down to the walls below. All of those numbers trace back to the same design speed. Edges, rakes and ridges fail first in a wind event, because that’s where uplift pressure concentrates most, which is why code nailing patterns tighten up in those zones rather than staying uniform across the whole field of the roof.
Does New Jersey require an ice barrier under the shingles?
An ice barrier is a self-adhering membrane installed under the shingles, run up from the eave edge past the point where the exterior wall meets the roof below. Its job isn’t to stop snow from sitting on the roof. It’s to stop meltwater that backs up behind an ice dam from finding a seam and reaching the wood deck underneath.
What actually causes an ice dam
An ice dam forms 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 the slope under the snow layer until it reaches the eave overhang, which sits beyond the heated space and stays cold. There, it refreezes, and over time that ice ridge grows into a dam that backs water up under the shingles above it. Newark’s coldest-month mean daily minimum temperature sits at 25.5°F under NOAA’s 1991-2020 climate normals, which means genuinely cold stretches with routine freeze-thaw cycling are a normal winter feature here, not a rare edge case. That’s exactly the climate pattern an ice barrier provision is written for.
The membrane’s job, and its limit
New Jersey’s residential construction rules run through the New Jersey Uniform Construction Code, One- and Two-Family Dwelling Subcode (N.J.A.C. 5:23-3.21), based on the 2024 International Residential Code in a New Jersey edition, and enforced statewide by the New Jersey Department of Community Affairs, Division of Codes and Standards. It’s a uniform code a municipality cannot weaken, though the permit itself is still issued and inspected locally. That 2024 edition took effect on 17 August 2026, with a six-month grace period during which the 2021 edition could still be used, so ask your building department which edition applies to your specific permit.
Given Newark’s winter temperature profile, expect your local building department to require an ice barrier membrane at the eaves on a re-roof, and confirm the exact extent and any local amendment with them directly rather than assuming a number. What the membrane cannot do is stop the dam from forming in the first place. Only air sealing the attic floor and adding enough insulation to keep the roof deck cold stop the melt-refreeze cycle that builds the dam. A homeowner who installs the membrane and does nothing about attic air leaks and insulation has bought protection against the symptom, not the cause, and will likely still see ice ridges at the eave every winter.
What roofing material suits New Jersey best?
Weighing the categories against local loads
Newark’s converted roof snow load of roughly 18 psf, its 115 mph basic wind speed, and a climate split across IECC zone 4A in 14 counties and zone 5A in 7 counties together set the terms for this choice, and none of the three points to one obviously correct material.
Architectural asphalt shingles are rated for wind by the manufacturer’s published ratings, but that rating only holds if the nailing pattern matches what the design wind speed requires. A high-wind-rated shingle nailed to a lower standard performs at the lower standard, full stop, so fastening quality decides performance as much as the shingle itself, a step our broader roofing guide covers in more depth.
Standing-seam metal sheds snow well, which is an advantage for the load sitting on the roof and a design problem for whatever sits below it. A metal roof that sheds a full winter’s accumulated snow load in one slide can drop it onto a doorway, a walkway or a driveway with real force, so where that snow lands has to be a deliberate design decision, not an afterthought discovered the first time it happens.
Slate and concrete tile add their own substantial dead weight on top of the snow load the structure already has to carry. That’s a different problem from wind or snow alone: the framing has to be sized from the start for the tile’s weight plus the design snow load together, not simply swapped onto framing built for asphalt shingles.
The climate zone split also matters here indirectly. Counties in zone 5A need more attic insulation than those in zone 4A to hold the same indoor comfort, and that insulation level is exactly what limits how much heat reaches the underside of the roof deck in winter, tying this choice back to the ice-dam mechanism above. Check the county table or the ENERGY STAR map for which zone applies to your address, since the two zones call for different rows on the insulation table and this page can’t tell you which one is yours.