How Heavy Snow Can Damage a Commercial Flat Roof
Winter weather can create serious challenges for commercial buildings, especially those with flat or low-slope roofing systems. Heavy snowfall, ice accumulation, freezing temperatures, and repeated freeze-thaw cycles can all place additional stress on a commercial roof.
For building owners and property managers in New Jersey, understanding how snow affects a commercial flat roof can help prevent leaks, drainage problems, structural concerns, and costly repairs.
R Stevens Commercial Roofing, located at 1312 Pleasant Valley Way, West Orange, NJ 07052, provides commercial roofing services throughout New Jersey and helps businesses maintain roofing systems through changing seasonal conditions.
Why Heavy Snow Is a Concern for Commercial Flat Roofs
Flat roofs are designed to handle normal weather conditions, but snow can become especially problematic when it accumulates faster than it melts or drains away.
Unlike steep-slope roofs, where snow may naturally slide off, commercial flat roofs can hold significant amounts of snow for extended periods.
As snow accumulates, it adds weight to the roofing system. Wet, compacted snow is especially heavy and can place considerably more stress on a roof than light, powdery snow.
The risk becomes greater when several storms occur close together without enough time for the existing snow to melt.
Snow Can Add Significant Weight to the Roof
One of the biggest concerns with heavy snowfall is the additional load placed on the building.
Fresh snow is often relatively light, but as temperatures fluctuate, it can become denser and heavier. Rain falling on existing snow can increase the weight even further.
Ice buildup can also add substantial weight.
Commercial roofs are engineered to withstand specific loads, but unusually heavy accumulation can still create problems, especially if the roof already has structural weaknesses or drainage issues.
Warning signs of excessive roof load may include:
- Unusual roof sagging
- Cracking or popping sounds
- Ceiling movement
- Doors or windows becoming difficult to open
- Visible structural movement
- Large amounts of standing snow or ice
If there are concerns about excessive snow accumulation, a commercial roofing professional should evaluate the situation before anyone attempts to remove snow from the roof.
Melting Snow Can Cause Roof Leaks
Snow itself is not always the main problem. The water created as snow begins to melt can expose weaknesses in a commercial roofing system.
If a roof has damaged seams, punctures, deteriorated flashing, or worn membrane areas, melting snow may find its way into the building.
Leaks can develop around:
- Roof penetrations
- HVAC equipment
- Flashing
- Drains
- Seams
- Skylights
- Parapet walls
- Roof edges
Even small roofing defects can become more noticeable during winter because water may repeatedly freeze and thaw around them.
A roof that appears fine during dry weather may suddenly begin leaking after several inches of snow begin to melt.
Freeze-Thaw Cycles Can Make Existing Damage Worse
New Jersey winters often involve frequent changes in temperature.
During the day, sunlight or warmer temperatures may cause snow and ice to melt. At night, temperatures may drop below freezing again.
This repeated freeze-thaw cycle can be hard on commercial roofing systems.
Water can enter small cracks or openings and then expand when it freezes. Over time, this process can make existing damage worse.
Repeated freezing and thawing may affect:
- Roofing membranes
- Seams
- Flashing
- Drainage systems
- Roof edges
- Penetrations
- Sealants
Small roofing issues that might otherwise remain manageable can become larger problems after repeated winter weather exposure.
Snow and Ice Can Block Roof Drains
Proper drainage is essential for commercial flat roofs.
Roof drains, scuppers, and gutters are designed to move water away from the building. During winter, these drainage systems may become blocked by snow, ice, leaves, or other debris.
When melting snow cannot drain properly, water may begin to collect on the roof.
Standing water can increase the weight on the roofing system and may increase the chance of leaks.
Blocked drains can also contribute to ice formation when water refreezes.
Before winter weather arrives, roof drainage systems should be inspected and cleared to help reduce the risk of backups.
Ponding Water Can Develop After Snow Melts
Ponding water occurs when water remains on a flat roof instead of draining away.
After heavy snowfall, large amounts of meltwater can develop in a relatively short period of time.
If the roof has low spots or drainage issues, that water may remain on the surface.
Persistent ponding water can place additional stress on the roofing membrane and may contribute to premature deterioration.
It can also make existing leaks more severe.
Building owners should pay attention to areas where water regularly collects after storms.
Repeated ponding may indicate that the roof needs drainage improvements, repairs, or further evaluation.
Ice Can Damage Roofing Components
Ice accumulation can create another set of problems for commercial roofs.
Water may freeze around drains, flashing, seams, and roof edges. As ice expands, it can place pressure on roofing materials.
Ice can also form around rooftop equipment and penetrations.
In some cases, large sheets of ice may remain on the roof long after surrounding snow has melted.
Removing ice improperly can damage the roofing membrane, especially if sharp tools or aggressive scraping methods are used.
Commercial roof snow and ice removal should be handled carefully to avoid creating additional damage.
Wind Can Make Snow Problems Worse
Winter storms often bring strong winds along with snow.
Wind can cause snow to drift into certain areas of a commercial roof, creating uneven accumulation.
For example, snow may collect around:
- Parapet walls
- HVAC equipment
- Mechanical units
- Roof transitions
- Higher building sections
These drifts may create heavier localized loads than the rest of the roof.
Strong wind can also affect loose roofing materials, flashing, or membrane sections that were already damaged.
After a major winter storm, a commercial roof inspection can help identify problems that may not be visible from inside the building.
Should Snow Be Removed From a Commercial Roof?
Not every snowfall requires roof snow removal.
However, unusually heavy accumulation, repeated storms, drifting, or existing structural concerns may make removal necessary.
Building owners should avoid sending untrained employees onto a snow-covered roof.
Winter roofs can be extremely slippery, and skylights, drains, edges, and rooftop equipment may be hidden beneath the snow.
There is also the risk of damaging the roofing membrane with shovels or other tools.
When snow accumulation becomes a concern, it is safer to contact experienced professionals who understand commercial roofing systems and winter roof conditions.
How to Prepare a Commercial Roof for Winter
Preventative maintenance can help reduce the risk of snow-related roof damage.
Before winter arrives, commercial property owners should consider scheduling a roof inspection.
A professional inspection can help identify:
- Loose or damaged flashing
- Open seams
- Punctures
- Drainage problems
- Clogged roof drains
- Deteriorated sealants
- Membrane damage
- Areas of ponding water
- Previous leak locations
Addressing small problems before the first major snowfall can help prevent them from turning into larger winter repairs.
Watch for Signs of Roof Problems After Heavy Snow
After a major snowstorm, property owners should monitor the building for potential signs of roof trouble or storm damage.
These may include:
- Water stains on ceilings
- Active leaks
- Damp insulation
- Bubbling or blistering roofing material
- Standing water
- Clogged drains
- Sagging areas
- Unusual odors
- Moisture around walls or ceilings
Even a small leak should be investigated quickly.
Water can travel beneath roofing materials before becoming visible inside the building, so the source of a leak may not always be directly above the interior stain.
Commercial Roof Inspections After Winter Storms
A professional commercial roof inspection can help identify damage caused by snow, ice, wind, and temperature fluctuations.
Roofing contractors can evaluate the membrane, seams, flashing, drainage systems, penetrations, and other important components.
Routine inspections are especially valuable after severe winter weather.
Finding problems early may help reduce repair costs and extend the life of the roofing system.
Commercial Roofing Services in New Jersey
New Jersey winters can place significant stress on commercial flat roofing systems.
Heavy snow, ice accumulation, melting water, blocked drains, freeze-thaw cycles, and strong winds can all contribute to roofing problems.
Property owners can reduce the risk of serious damage by monitoring snow accumulation, maintaining drainage systems, scheduling routine inspections, and addressing roofing problems promptly.
R Stevens Commercial Roofing, located at 1312 Pleasant Valley Way, West Orange, NJ 07052, provides commercial roofing services throughout New Jersey.
For businesses dealing with winter roof damage, leaks, drainage problems, or concerns after heavy snowfall, R Stevens Commercial Roofing can inspect the roofing system and recommend appropriate repair or maintenance solutions.
