Quick Answer When Should Your Remove Snow From Your Roof? Most residential roofs are designed to handle a specific snow weight — not depth. As
Quick Answer
When Should Your Remove Snow From Your Roof?
Most residential roofs are designed to handle a specific snow weight — not depth. As a general rule, act before snow accumulation reaches your roof’s load limit.
20-25 lbs/sq. ft.
average residential roof capacity
~12"
of wet, heavy snow to hit that limit
6"
of ice can be as heavy as 3+ ft of fresh snow
Snow removal is essential for the safety and proper functioning of your roof. Until now, you’ve probably removed snow from your roof when it seemed about right. Still, you might have wondered how deep you should allow the snow to get before taking it off your rooftop.
Table of Contents
What is Snow Load?
Snow load is the downward force exerted on a roof by the weight of accumulated ice and snow. While many houses are built to be durable and last many years, the weight of heavy snow and ice can impact the structural integrity of the roof and the house itself.
The average residential roof can support 20 to 25 pounds of snow per square roof. In snowy climates, however, roofs are designed to support a heavier snow load.
If the weight of snow and ice exceeds what the roof was designed to shoulder, the roof or entire structure can collapse under pressure.
Non-compliance with building code requirements, poor construction, weak roofing materials, inadequate roof drainage, and uneven snow load distribution can further lead to an overstressed roof. Also, snow can accumulate in one area of the roof, creating an increased snow load on some parts of the roof.
The Weight of Different Types of Snow or Ice
The weight of one foot of snow can range from 3 to 30 pounds per square foot (PSF), depending on its moisture content. The actual water content of snow generally ranges from 3% for dry snow to 32% for wet, heavy snow, and about 99% for ice.
The general weight ratio for normal snow is 10:1. This implies that for every 10 inches of snow there is about an inch of liquid content. Fluffy snow is lighter since it doesn’t have as much water content. Fluffy snow has about 1 inch of liquid content in 15 inches of snow. Wet snow is heavier than fluffy snow and holds the most moisture. The ratio is 5:1; for every 5 inches of snow, there’s 1 inch of water.
An inch of water weighs about 5.2 pounds per square foot. As such, a roof designed to carry a snow load of 20 pounds per square foot can support about 12 inches of wet, heavy snow.
Snow density is a function of wind exposure, temperature, and time. Snow will compact over time as it experiences more changes in temperature and wind, and as new snow layers are added to the roof. Warmer temperatures lead to higher liquid content. And when temperatures drop, the water may re-freeze into ice.
| Snow / Ice Type | Density (PSF) | Risk Level |
|---|---|---|
|
Ice |
57.25 |
Extreme |
|
Wet, heavy snow |
46.82 |
Very High |
|
Wind-packed snow |
23.41 |
Moderate |
|
Settled snow |
15.61 |
Moderate |
|
Damp, freshly fallen snow |
6.87 |
Low-Moderate |
|
Fresh / fluffy snow |
3.75 |
Low |
Which Roofs Handle Snow Best?
Slope, design complexity, and roofing material all determine how much snow stays on your roof — and how long it stays there.
A roof with a slope steeper than 7:12 or 5:12, for instance, will allow snow to slide off more readily. Roofs in snowy climates should have at least a 10-degree pitch.
While the angle and pitch of a roof help shed snow, having too many angles for aesthetic purposes could cause problems with snow shedding. Complex designs with many slopes, corners, hips, and valleys disrupt the ability of a roof to shed snow.
Sheds Snow Well
- Steep pitch (7:12 or greater)
- Simple, clean roof lines
- Metal roofing panels
- Single-ply membrane
- Roofs with ≥10° pitch (snowy climates)
Prone to Overload
- Flat or low-pitch roofs
- Complex angles, valleys, hips
- Dormers & skylights (disrupts shedding)
- Asphalt shingles / aggregate finishes
- Layered reroof (extra dead load)
Ice Dams and Your Roof
Snow cover on your roof, heat loss from your living spaces, and outside temperatures interact to form ice dams. Warm, moist air from your home will naturally rise to the attic. If there’s poor roof ventilation, your roof will become warm and melt the accumulated snow.
Snow melt will then flow down and re-freeze into ice when it hits the colder edges of the roof, forming an ice dam. If this repeatedly happens, the ice will grow as it is fed by the melting snow.
Water can back up behind the ice dam and find its way into the attic space through cracks and openings in the exterior roof covering. From the attic, the water could flow into the ceiling and interior walls.
You can minimize the impact of ice dams through proper and adequate attic ventilation and insulation.
Pre-Winter Roof Inspections to Prevent Damage
Heavy snowfall can threaten the safety and structural integrity of your roof. Therefore, it’s important to have your roofing system inspected by a roofing contractor before snow falls. The roofer will look out for deterioration, damage, or other weaknesses that are indicators of possible snow-load trouble.
The inspection will cover different areas, including:
- Exhaust-vent openings
- Gutters and downspouts
- Cold-eave heaters
- Ridge and soffit vents
- Attic
- Rooftop flashing
- Roofing materials
In addition to checking for gaps, cracks, missing seals, and penetration on roof surfaces, they will also inspect roof trusses to make sure they are intact and uncompromised. Your roof needs to be strong enough to endure the pressure of drifted and packed snow.
For thorough roof inspections and help minimizing the risks associated with heavy snow loads, contact us at Adam Vaillancourt Roofing & Gutters, your residential roofing experts in the Southern New Hampshire and Northern Massachusetts area. We know what works best in this area.
Frequently Asked Questions
How do I estimate the snow load on my roof right now?
Measure the depth of snow in inches, then identify the type (fresh/fluffy, settled, wet). Multiply depth × density per inch. For example, 18 inches of wet snow at ~3.9 PSF/inch = roughly 70 PSF — well above a typical residential roof’s 20–25 PSF capacity. When in doubt, call a roofing professional.
Does roof pitch really affect how much snow stays on it?
Yes, significantly. Roofs steeper than 7:12 allow snow to slide off more readily. Below that threshold — especially flat roofs — snow accumulates and takes much longer to drain or melt off. Metal roofing on a steep pitch is the most effective combination for shedding snow quickly.
What are the warning signs of an overloaded roof?
Look for: creaking or popping sounds from the roof structure, doors or windows that suddenly stick or won’t close properly, visible sagging along the roofline or ceiling, and cracking in interior walls or ceiling drywall. Any of these warrant immediate action. Remove snow carefully or call a pro.
Can I remove snow myself?
For single-story homes with accessible edges, a roof rake (long-handled tool used from the ground) is generally safe for removing the lower 3–4 feet of snow without climbing. Avoid shoveling directly on the roof — it’s a fall risk, and aggressive scraping can damage shingles. For large accumulations or multi-story homes, hire a professional.
Additional Roofing Resources
EPDM roofing material is the smooth black surface stretched across flat garages, apartment buildings, and commercial rooftops. Unlike shingle roofs that draw attention with texture
Have you ever stepped back from your house and noticed a dip or curve in the roofline where it should be straight? If you have,