Oh, winter! The snow, the holidays, the cheer. But what does winter mean to your flat roof? There are a number of season-specific challenges your facility's roof may face in the next few months, particularly if your building experiences extreme weather.
Heavy snow:
While looking deceivingly weightless in the air, snow may generate a lot of pressure when accumulated on your roof. One inch of wet, dense snow equals 1.66 lbs/sq. ft. It may only take a few inches of snow to generate enough extra weight to cause damage, sag and even the collapse of your facility's roof.
Freeze and thaw cycles:
During winter, the outside temperature fluctuates throughout the day and typically drops at night. When your roof's temperature changes from below freezing to above freezing and back, it is called a freeze-thaw cycle. Your building's interior temperature contributes to this process by melting the lowest layer of snow as well. This impacts your roof in a few ways. First, snowmelt or rainwater may seep into tiny cracks on your roof's surface or weak points in seams (if applicable) when temperatures are above freezing. Once the outside temperature drops enough to compensate for the building's warmth, that water will start freezing and expanding, causing the cracks to grow with it. Additionally, the same freeze-thaw cycle densifies the snow accumulated on your roof and contributes to ice dams (see below).
Thermal shock:
When roof materials undergo abrupt changes in temperature due to extreme weather, they are forced to expand and contract over and over. Those cycles generate pressure on the roof's seams and flashings which may lead to cracks and other damage, weakening your roof system.
Ice dams:
Ice dams may occur when the show melts (and then freezes) unevenly from one roof section to another. It is a ridge of ice that typically forms at the roof's edge and prevents proper drainage. Once the water backs up behind an ice dam, it adds additional weight to that area and can penetrate your roof through any weak points it can find.
Safety concerns and property damage:
Snow and ice accumulation on your facility's roof may eventually fall off and can cause damage or injuries to people or property below. On the rooftop itself, ice may become a slip hazard. Excessive snow may block access to your building's vital features, including HVAC units and exhaust vents.
So, what to do?
Start with a comprehensive evaluation to determine your current roof's condition. Storms, UV exposure, vegetation growth and other factors may have created opportunities for water intrusion that you can't see yet. Based on the inspection results, complete all needed repairs as soon as possible - once the snow hits your roof, servicing it will be much more complicated. But what can you do about the snow? There are a few options as well:
✔ Snow removal:
We recommend enrolling in our snow removal plan. You will have priority scheduling for rooftop snow removal with all the safety requirements in place.
✔ Snow monitoring:
The amount of snow on the ground doesn't necessarily represent what is on your roof. CentiMark's sensor-based snow monitoring system allows you to track the actual snow level on your roof and address the uneven distribution of snow weight due to architectural elements or slopes. You can monitor your snow levels from anywhere via a customer portal. Once the weight reaches the established point, our crew will be dispatched to perform the snow removal.
✔ Accessories:
Installing snow management devices like snow guards or heat cables will allow you to control the movement of snow on your rooftop, particularly for metal roofs and slopes.
The cold weather is here and some parts of North America are already experiencing snowfall. Having a solid plan for this winter season is crucial to keep your building watertight. Need help or have questions regarding winter-specific roof maintenance? We are just a call away! Our experienced, highly-trained crews truly understand your local weather challenges because, well, they are your neighbors.
