How Much Snow Can a Roof Hold? Weight, Warning Signs, and What to Do
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There's no single number of inches, because a roof carries weight, not depth, and how much it can hold depends on how it was built. Roofs are designed for the snow load in the local building code, and an older or deteriorated roof may hold less (OSHA, FEMA). FEMA's Snow Load Safety Guide says a foot of fresh snow weighs from about 3 pounds per square foot when it's light and dry to 21 when it's wet and heavy, and a foot of ice weighs about 57. The Maine Emergency Management Agency, citing the Insurance Institute for Business and Home Safety (IBHS), says 3 to 5 inches of old, packed snow weighs about as much as a foot of new snow, and that a typical roof can handle about 20 pounds per square foot. FEMA says most buildings aren't at risk and removing roof snow is often more hazardous than beneficial. Act when snow is unusually deep and heavy, especially after rain or repeated storms, and get out right away if you see the warning signs below.
If the ceiling sags, you hear popping or cracking, or doors suddenly stick, get everyone out of the house. FEMA says a building showing these signs should be promptly evacuated and inspected by a local building official or a qualified design professional, such as a structural engineer, before anyone goes back in. Don't climb up to shovel it off.
What Snow and Ice Weigh
Water content makes snow heavy, so the same depth can weigh very different amounts from storm to storm (OSHA, FEMA). These are rough figures, not a rating for your roof.
| Snow or ice | Approximate weight | Source |
|---|---|---|
| Fresh snow, light and dry | About 3 lb per square foot for each foot of depth | FEMA P-957 |
| Fresh snow, wet and heavy | About 21 lb per square foot for each foot of depth | FEMA P-957 |
| New snow, rule of thumb | 10 to 12 inches equals about 1 inch of water, or about 5 lb per square foot | Maine EMA, citing IBHS |
| Old, packed snow | 3 to 5 inches equals about 1 inch of water, or about 5 lb per square foot; more than 2 feet could be too much for a typical roof | Maine EMA, citing IBHS |
| Ice | A little under 5 lb per square foot per inch; about 57 lb per square foot per foot | FEMA P-957 |
| 2 feet of old snow plus 2 feet of new | As much as 60 lb per square foot, beyond what most roofs are built to carry | Maine EMA, citing IBHS |
Roofs in snowy areas may be designed for more than 20 pounds per square foot; your local building department can tell you the design load for your area (Building America Solution Center). FEMA adds that a house built 40 years ago may not have been designed for snow loads as they're understood today.
Snow also gets heavier as it sits. FEMA says a short rain can soak the snowpack and significantly increase the load, and snow that softens in the sun gets denser and refreezes. Repeated storms stack up too, so if more snow is on the way, FEMA says clearing the roof in between lowers the risk.
Warning Signs of Too Much Snow on a Roof
FEMA says an overstressed roof usually gives some warning. Watch for:
- Sagging ceilings, or a roofline or roof boards that dip.
- Popping, cracking, or creaking noises from the roof or attic.
- Doors or windows that suddenly won't open or close.
- New cracks in walls, ceilings, or masonry, and cracked or split wood framing.
- Severe roof leaks, or water collecting where it shouldn't on a low-slope roof.
- Bowed or bent supports in the attic, such as the bottom boards of trusses.
If you see any of these, don't wait to see whether it gets worse: leave the house and call the local building department or a structural engineer for an inspection (FEMA). Don't go up on the roof; the Building America Solution Center notes that your weight adds to a roof that's already stressed.
What to Do About Heavy Snow
Clear what you can from the ground
On a one-story roof, a roof rake lets you pull snow down from the ground. FEMA says to use a long-handled, non-metallic rake and avoid metal ones, which can damage the roof and pose an electrocution risk.
- Take a little at a time. Start at the edge and work your way up (Maine EMA). OSHA warns that falling snow can hit or bury the person raking, so pull small amounts and stay back from the eave; FEMA says roof snow can slide at any moment.
- Leave a few inches. FEMA says to leave at least a couple of inches of snow on the roof, and Maine EMA says to shave it down to 2 or 3 inches; scraping down to the shingles can damage them and cause leaks.
- Keep the area below clear. OSHA says to keep people back 10 feet from where the snow will land and to wear eye and head protection. FEMA warns that even a short-falling icicle can injure.
- No heat or flame. Maine EMA says never to melt roof snow or ice with a hair dryer, heat gun, or open flame.
Look up for power lines first
OSHA says to keep at least 10 feet between any power line and you, the pole, and the rake, and to treat every line as energized, even if it's down or looks insulated. Maine EMA says to find where the service line enters your house and stay well away from that area. If the snow is near a line, leave it to a professional.
Never climb onto a snowy roof
OSHA's investigations find falls cause the most deaths and injuries in rooftop snow removal. Maine EMA says anything that requires getting onto your roof may be too dangerous for anyone but a trained professional with safety gear, and says no to ladders. FEMA says roof snow removal should be done only by qualified people following OSHA fall-protection practices. For a second story, a steep or low-slope roof, or a heavy load, hire a roofer or snow-removal contractor, and line one up early: FEMA notes contractors are hard to find once a storm hits.
Clear drains, gutters, and vents
- Roof drains and downspouts. FEMA says to check drains, gutters, downspouts, and vents for snow and ice after each storm, and Maine EMA says to keep downspouts clear at ground level so meltwater can get away.
- Furnace and water-heater vents near the ground. If yours vent through pipes on an outside wall, snow and drifts can bury them. Connecticut's Department of Emergency Services and Public Protection warns that when snow blocks these intake and exhaust vents, deadly carbon monoxide can build up inside the home. The U.S. Fire Administration says to keep the dryer, furnace, stove, and fireplace vents clear of snow, too. Check them after every storm and after drifting.
- Keep your CO alarms working. If one sounds, get everyone into fresh air and follow our guide to a carbon monoxide alarm going off.
Ice Dams Add Weight at the Eaves
When heat from the house melts roof snow and it refreezes at the cold edge, it forms an ice dam. FEMA says ice dams create a concentrated load at the eaves and make it harder for a sloped roof to shed snow. Don't chip at it or climb up to it. Our ice dam guide covers what to do from the ground and how to fix the attic heat loss that causes them.
Flat Roofs, Drifts, and Lower Roofs
FEMA says uneven snow loads are a greater risk than a uniform layer, because extra weight piles up in a few spots. Watch:
- Flat and low-slope roofs. Maine EMA says they're at the greatest risk of buckling under heavy snow and ice. They hold snow longer than pitched roofs, and if drains are blocked, meltwater can pond in low spots and add a concentrated load (FEMA).
- Lower roofs below higher ones. Wind drifts snow into the sheltered side of a higher roof, and snow sliding off an upper roof lands on porch roofs, sunrooms, and entry canopies. FEMA says the impact of sliding snow can itself overload a lower roof.
- Valleys and obstructions. Snow piles deeper where two roof slopes meet and against chimneys, dormers, and skylights (FEMA).
- The side away from the wind. Drifts commonly build on the downwind side of a ridge (FEMA).
Does Insurance Cover a Roof That Collapses From Snow?
Usually, under most homeowners policies. The Insurance Information Institute (Triple-I) lists "weight of ice, snow or sleet" as a covered peril on the common homeowners policy forms, including the HO-2 and HO-3, but not the basic HO-1. Triple-I also says standard homeowners policies don't cover flooding, so melting snow that seeps in from the ground up needs flood insurance. Coverage varies, so read your policy.
Frequently Asked Questions
How much snow is too much for a roof?
It depends on the snow's weight and your roof's design. The Maine Emergency Management Agency, citing IBHS, says a typical roof can handle about 20 pounds per square foot of added weight, which it puts at up to about 4 feet of new snow or about 2 feet of old, packed snow, and less on an older roof or one that's had problems. Wet snow and ice get there much faster.
How much does a foot of snow weigh?
FEMA's Snow Load Safety Guide says a foot of fresh snow weighs from about 3 pounds per square foot for light, dry snow to about 21 for wet, heavy snow. A foot of ice weighs about 57 pounds per square foot.
Should I remove snow from my roof?
Usually not for weight. The Building America Solution Center says it usually isn't needed unless the house is older, was built to questionable standards, or is carrying an unusually heavy load. Raking the lower few feet from the ground is mostly about ice dams. For anything you can't reach from the ground, hire a professional.
How do I know if my roof is in danger of collapsing?
FEMA's warning signs include sagging ceilings or roof boards, popping, cracking, or creaking noises, doors or windows that suddenly stick, new cracks in walls or ceilings, cracked or split framing, and severe leaks. If you notice any of them, get everyone out and have a building official or structural engineer inspect the house before you go back in.
The Bottom Line
A roof carries weight, not inches, and most homes handle normal snow. Worry about wet snow, ice, rain on snow, drifts, and repeated storms. If the ceiling sags, the house pops or creaks, or doors stick, get out and call a building official or structural engineer. Otherwise, rake from the ground with a non-metallic rake, leave a few inches, stay 10 feet from power lines, never climb up, and keep drains and furnace and water-heater vents clear.
Sources
- FEMA — Snow Load Safety Guide, FEMA P-957 (PDF, January 2013, via the Whole Building Design Guide) (most buildings not at risk; removal often more hazardous than beneficial; fresh snow 3 to 21 lb per square foot per foot; ice a little under 5 lb per square foot per inch and about 57 per foot; older buildings and drifting provisions; rain on snow, melt and refreeze, ponding; drifts, sliding snow, valleys, chimneys, dormers, porch roofs; ice dams load the eaves; warning signs; evacuate and call a design professional; check drains, gutters, downspouts, and vents between storms; contractors scarce during storms).
- FEMA — Snow Load Safety Guidance, FEMA P-957 (PDF) (warning signs of overstress; evacuate and call a building authority or design professional; removal only by qualified people following OSHA protocol; leave a couple of inches of snow; long-handled non-metallic rake from the ground; avoid metal rakes; snow can slide at any moment; falling icicles).
- OSHA — Falls and Other Hazards to Workers Removing Snow from Rooftops and Other Elevated Surfaces (PDF) (snow weight depends on water content; roof capacity set by local building code and reduced by deterioration; falls cause the most fatalities and injuries; snow rakes from the ground; small amounts to avoid being buried; keep people back 10 feet; eye and head protection; at least 10 feet from any power line, treated as energized).
- Maine Emergency Management Agency — removing snow from roofs (citing IBHS: typical roof handles about 20 lb per square foot; new snow, packed snow, and ice weights; 2 feet of old plus 2 feet of new up to 60 lb per square foot; flat and low-pitched roofs at greatest risk; consider professionals; rake from the edge, small amounts, shave to 2 or 3 inches; aluminum rakes conduct electricity; stay away from the service line; no ladders, heat guns, or open flame; keep gutters, drains, and downspouts clear; signs of a stressed roof).
- Building America Solution Center (DOE/PNNL) — managing snow loads on roofs and decks (removal for weight usually unnecessary except for older homes, questionable construction, or extraordinary loads; roofs in snowy areas may be designed for more; check with the local building department; melt-refreeze, rain on snow, and repeated storms).
- Connecticut Department of Emergency Services and Public Protection — safety concerns following the winter snow storm (snow blocking furnace and water heater intake and exhaust vents can cause deadly carbon monoxide to build up inside).
- U.S. Fire Administration — carbon monoxide poisoning prevention (keep dryer, furnace, stove, and fireplace vents clear of snow and debris).
- Insurance Information Institute (Triple-I) — which disasters are covered by homeowners insurance? (weight of ice, snow, or sleet a covered peril on HO-2, HO-3, and other forms, not HO-1) and mitigation reduces winter weather risks (December 2024; flooding not covered by standard homeowners policies; melting snow seeping in from the ground up needs flood insurance).
Last reviewed October 15, 2026. General information, not professional advice — a sagging ceiling or other warning signs, any roof you can't clear from the ground, and any work near a power line belong to a building official or structural engineer, a qualified roofer or snow-removal contractor, or your electric utility.