Most commercial roofs don’t need snow removed after every storm. Removal makes sense when the snow load is getting close to what your roof was designed to hold, or when more snow is coming on top of what’s already there. For smaller amounts, the risk of damaging the roof or hurting someone often outweighs the benefit. When snow does have to come off, it should be done by a licensed, insured roofing contractor, using plastic tools, and never all the way down to the membrane.
That last part surprises a lot of facility managers. Here’s how to tell what your roof needs this winter, and what to do before the first big storm.
When Snow Removal Is Worth It
FEMA’s Snow Load Safety Guide says the design snow load of your building is the key to deciding when to begin removal, and that if the existing snow load is close to the capacity of the roof structure, snow removal is prudent. Removal can also make sense after a storm if the snow could melt, refreeze, and add weight, or when more snow is in the forecast.
A few situations where we’d say it’s time to call someone:
- Heavy accumulation after several storms. Snow that never gets a chance to melt between storms stacks up fast
- Drifts. Wind can pile snow against parapets, equipment, and elevation changes, so one corner may carry far more than the rest of the roof
- Ice underneath. A layer of ice under the snow adds weight and can make the pack harder to remove
- Older roofs or ones with known problems. If your roof has ponding water, a history of leaks, or hasn’t been evaluated recently, it’s less forgiving
If you’re not sure where your building stands, that’s a good reason to have someone look at it before the snow flies, not after.
When It’s Better to Leave the Snow Alone
This is the part nobody warns you about. Facilitiesnet notes that a foot or less of snow probably doesn’t need to be removed unless ice has formed underneath. And FEMA’s guidance says that for minor accumulations, the likelihood of damaging the roofing material or the risk of being on a roof outweighs the benefits of removal.
In other words, a few inches on a sound roof isn’t an emergency, and sending someone up with a shovel can cause the exact problem you’re trying to avoid. A cut in a membrane, a damaged flashing, or a crushed drain cover is a leak waiting for the first thaw.
Never Take It Down to the Membrane
If snow does need to come off, the goal isn’t a bare roof. FEMA says at least 2 inches of snow should be left on the roof, and warns that removing snow completely can result in serious damage to the roof covering. That thin layer is a buffer between your tools and your membrane.
A few other basics from the same guidance:
- Don’t use mechanical snow removal equipment
- Don’t use sharp tools like picks or ice chippers
- Use plastic shovels, not metal
- Avoid metal snow rakes, which can damage roofing material
- Remove drifted snow first, then work on the rest of the roof
Our blog post on preparing your commercial roof for Michigan winters covers how drains, flashing, and ponding water play into all this.
Warning Signs That Mean Act Now
Sometimes the roof tells you it’s carrying too much. FEMA lists warning signs that include sagging roof members, popping, cracking, or creaking noises, bowing trusses, doors or windows that suddenly stick, cracks in walls, and excessive water collecting on a low slope roof.
If you see any of these, don’t send anyone up. FEMA says the building should be promptly evacuated and a qualified design professional contacted. Call a structural engineer and a roofing contractor, in that order.
Why Snow Removal Should Be a Pro’s Job
Roof snow removal is dangerous work. It happens at height, on slippery surfaces, in the cold. FEMA’s guidance says it should be performed by a licensed, insured professional roofing contractor who has experience with roof snow removal, and that OSHA rules for rooftop work apply, including fall protection where applicable.
There are a couple of traps that don’t look like traps. Skylights buried under snow are a serious fall hazard. And someone needs to keep people away from the ground below, since snow and ice come down fast.
A roofing contractor also knows where the weak points are. They can tell a flashing from a pipe boot from a drain, and they’ll check for damage as they go instead of discovering it in March.
Build Your Snow Plan Before the First Storm
The worst time to figure this out is during a blizzard. Take care of these now:
- Know your roof. Find out the design snow load and what your roof system is made of
- Mark what’s up there. Skylights, hatches, drains, vents, and equipment all need to be identified
- Schedule a fall inspection. Catch ponding water, worn seals, and damaged flashing while repairs are still possible
- Pick your contractor now. Choosing someone before a storm means you’re not calling around while everyone else is
- Decide your trigger. Agree ahead of time on what accumulation or warning signs will start the call
If your building has a maintenance program, snow response fits right in. Our Umbrella Program builds regular inspections and preventive care into your schedule, so someone is already watching your roof before winter hits.
What to Do If a Leak Shows Up
Melting snow and ice can find the weak spot in any roof. If you notice water coming in, contain it, protect equipment, and call for help. Our post on what to do when your commercial roof is leaking walks through the steps. We offer 24/7 emergency leak repair, and with certifications from over 20 roofing manufacturers, we do our repairs with the proper manufacturer’s materials so you don’t lose your warranty.
Talk to National Roofing & Sheet Metal
We’re a family owned and operated commercial and industrial roofing contractor based in Burton, and we’ve been serving Michigan since 1942. We do commercial and industrial work only, for businesses, government, and educational facilities. Free estimates and inspections are available, and we’re fully licensed and insured.
Call us at (810) 742-7373, Monday through Friday, 8am to 5pm, or reach out to us online any time.
Frequently Asked Questions
How much snow is too much for a commercial roof? It depends on your roof’s design snow load, which is why it’s worth knowing before winter. Heavy accumulation, drifts, ice, and rain on top of snow can all push a roof closer to its limit. If you’re unsure, we can take a look.
Should I remove snow from my flat roof after every storm? Usually not. For smaller accumulations on a sound roof, the risk of damaging the roof or injuring someone can outweigh the benefit. Removal makes more sense when the load is nearing capacity or more snow is on the way.
Can my maintenance staff shovel the roof? We’d recommend against it. Snow removal should be done by a licensed, insured roofing contractor, because it involves fall hazards and it’s easy to damage the membrane.
How much snow should be left on the roof? FEMA’s guidance says at least 2 inches should stay on the roof. That layer helps protect the membrane from tools.
What are signs my roof is overloaded? Sagging roof members, popping or creaking sounds, bowing trusses, doors or windows that stick, wall cracks, and water collecting on a low slope roof are all warning signs. If you see them, evacuate and call a qualified professional.
Can I use a snow blower or ice chipper on my roof? No. Mechanical equipment and sharp tools can damage the roofing material, and the damage often shows up as leaks later.
Do you offer emergency service in winter? Yes. We offer 24/7 emergency leak repair for commercial and industrial buildings.
National Roofing and Sheet Metal proudly serves commercial and industrial clients throughout the Michigan region, including Clio and Flint . Questions about commercial roof leak repair or any of our roofing services? Contact our team today.
