Flat roofs are particularly vulnerable to snow and ice. Their lack of a steep slope allows snow, water, and ice to accumulate, increasing the roof’s weight and stressing the building’s structural framework. In addition, snowmelt and ice can damage roof membranes, leading to water infiltration, leaks, and interior mold or mildew growth.
Here’s more about how snow affects a flat roof, signs of damage, and some tips to help prevent damage to your roof.
How Snow Affects a Flat Roof
A buildup of snow affects a flat roof in many ways due to its weight and water content:
Structural stress
Snow can weigh up to 8 pounds per cubic foot, while ice is up to 60 pounds per cubic foot. All this added weight stresses the building’s beams, which can cause the roof to sag, warp, or even collapse.
Additionally, excessive weight may push roof rafters outward, potentially damaging exterior walls.
While flat-roofed buildings are designed to carry a certain amount of snow load, the additional weight from snow and ice can exceed the capacity of even the strongest structure.
Water damage
The weight of snow and ice can force water beneath the roof membrane and structure, causing leaks. Also, if the roof doesn’t have enough slope or the drains are clogged, snowmelt can pool, seep into cracks, and refreeze. This expansion can damage the roof membrane and seams, leading to interior water intrusion and potential mold or mildew growth.
Drainage problems
Snow can also block roof drains, causing pooling and water damage, as described above.
Ice formation
Snowmelt and refreezing can damage the roof membrane, weaken seams, and create heavy ice that’s hard to remove.
Warning Signs to Look For
Here are some warning signs that you may have flat roof damage caused by snow or ice:
- Interior doors or windows are hard to open and close
- Ceiling stains or cracking drywall
- Drooping ceiling tiles or visible bowing in walls
- Visible sagging of the roof structure
- Popping, creaking, or cracking sounds
- Fire sprinkler lines or heads bending below the ceiling
- Thick ice buildup along roof edges or parapet walls
- Mold or mildew growth
How to Prevent Flat Roof Damage from Snow
- Ensure roof drains are operating properly before winter weather arrives.
- If your roof has a history of issues with snow load, consider reinforcing the structural framework.
- Ensure you have adequate roof insulation, which helps prevent snowmelt and refreezing.
- Call a professional roofer to inspect your roof in the fall to address issues before winter weather arrives.
- Hire snow removal services to safely remove snow and ice from your roof without damaging the roof membrane.
The professionals at New Roofs Inc. are here to help when winter weather arrives. Contact our team today to learn more about our commercial flat roof services.