As winter sets in, the accumulation of snow and ice on roofs can pose significant risks to both the structure of your home and your safety. De-icing your roof is a crucial winter maintenance task that helps prevent potential damage and ensures the safety of those in and around your home. In this post, we’ll explore effective methods and safety measures to safely de-ice your roof.
A Word of Caution
Before diving into de-icing methods, it's essential to understand the potential risks associated with accumulated snow and ice on a roof. The weight of snow can cause structural damage, while ice dams may block drainage, leading to leaks and water damage inside the house. Additionally, falling ice or snow from a roof can pose hazards to individuals below.
What is an ice dam?
An ice dam is a ridge of ice that forms at the edge of a roof and prevents melting snow (water) from draining off the roof. The water that backs up behind the dam can leak into a home and cause damage to walls, ceilings, insulation and other areas.
Effects of ice dams
Moisture entering the home from ice dams can lead to the growth of mold and mildew. These can cause respiratory problems.
Prevent the growth of mold and mildew by immediately drying out portions of the house that are wet or damp.
Take immediate action to get rid of the water source, clean the home environment and maintain its air quality.
What causes ice dams?
Nonuniform roof surface temperatures lead to ice dams. Heat loss from a house, snow cover and outside temperatures interact to form ice dams. For ice dams to form there must be snow on the roof and, at the same time, higher portions of the roof's outside surface must be above 32 degrees F (freezing) while lower surfaces are below 32F. These are average temperatures over sustained periods of time. For a portion of the roof to be below freezing, outside temperatures must also be below freezing.
The snow on a roof surface that is above freezing will melt. As water flows down the roof it reaches the portion of the roof that is below 32F and freezes. This causes the ice dam.
The dam grows as it is fed by the melting snow above it, but it will limit itself to the portions of the roof that average below 32F. So the water above backs up behind the ice dam and remains a liquid. This water finds cracks and openings in the exterior roof covering and flows into the attic space. From the attic it could flow into exterior walls or through the ceiling insulation and stain the ceiling finish.
What causes different roof surface temperatures?
Since most ice dams form at the edge of the roof, there must be a heat source warming the roof elsewhere. This heat primarily comes from the house. In rare instances, increased heat from the sun may cause these temperature differences. Ice dams can be prevented by controlling the heat loss from the home.
Here are 6 of the most common ways to remove snow, ice and ice dams from your roof this winter.
1. Rake Snowfall Off the Roof
Use a lightweight roof rake — ideally one with a long extension — so you can stay safely on the ground. While the snow is still soft, usually right after significant snowfall before it has a chance to refreeze, use the rake to clear your roof’s eaves of snow to reduce the potential for ice buildup.
It’s also a good practice to keep your eaves clear from buildup of leaves and branches before a snowfall. Keeping your gutters clear of debris can help water drain away from your roof instead of pooling onto it, which is how it could refreeze into an ice dam.
2. Add Attic Insulation
The freeze/ thaw cycle of snow and ice is caused by the warmth of your house and the cold air outside. To prevent heat transfer to the snow on your roof — and keep the energy in your home where it’s needed — investing in quality attic insulation will reduce the potential for ice dams to form and save you money on your energy bill.
3. Seal Interior Airflow Leaks and Ventilate Your Attic
Heat rises, meaning even with the best ventilation, warm air flowing from your living space can still mean your attic is too warm. The solution is to change the direction of hot air flow to prevent overheating. A quality insulating foam applied to any gaps around vent pipes, and rerouting bathroom and dryer vents from the attic to a side exterior wall of your home, can really help.
Attic vents can also be installed along the underside of roof eaves, and exhaust vents can be placed near the top of the roof. This keeps the air moving and helps with cooling instead of heat collection in your attic. For this, we recommend enlisting professional help, especially to make sure you develop an efficient ventilation system for your home’s specific roof and attic configuration.
4. Install De-Icing Cables
Most home improvement stores should have roof de-icing cables, which can be installed directly on top of your roof’s shingles or clipped over the eaves. They will prevent ice dams from forming, but you’ll have to be careful not to dislodge them if you are raking freshly fallen snow from your eaves. These can also help remove ice dams in a pinch.
5. Melt Ice Dams With Calcium Chloride
Calcium chloride is the same chemical used for melting ice on driveways and sidewalks, and it can help remove ice dams all the same. Though it is safe for shingles and vegetation, be careful not to sprinkle it directly on the ice dam: instead, fill tube socks or pantyhose legs with the granules and tie off their ends with string. Position each sock vertically over the ice dam, leaving the end of the sock an inch or two off the roof’s edge. As the calcium chloride causes the ice to melt, it will create a channel to allow additional water to melt and run safely off of the roof.
Warning: do NOT substitute calcium chloride with rock salt for this task. Sprinkling rock salt on your roof can result in shingle damage, as well as kill any landscaping or foliage underneath the eaves.
6. Break Up Ice Dams With a Mallet
In addition to the other techniques listed here, you may choose to clear the excess snow and ice from your roof by force. You can chip away at the ice with a roof-safe mallet to widen runoff channels and create better drainage. Be careful not to use tools that could cause further roof or shingle damage, such as an axe, hatchet or other sharp or heavy tool.
Since you don’t want to be underneath large banks of ice and snow that may slide and fall off your roof, you’ll need to be cautious and do this from a higher vantage point — likely on your roof. This is a somewhat dangerous task if you are not comfortable climbing onto a frozen roof, plus you’ll want to avoid injuring anyone or any foliage beneath you, so it may be best left to the professionals.
When to hire a professional
Roofing contractors are professionals who can deal with the heat transfer problem that creates ice dams.
The contractor you hire should conduct a blower door test to evaluate how airtight your ceiling is. They also may use an infrared camera to find places in the ceiling where there is excessive heat loss.
Do not repair interior damage until ceilings and walls are dry.
Interior repair should be done together with correcting the heat loss problem that created the ice dam or the damage will occur again.
Anyone on the roof during the winter or performing work on the roof from below risks injury and may cause damage to the roof and house.
It is important to contact professionals to carry out this job.
Whenever a house is tightened up, ventilation systems, exhausting devices and combustion devices must have enough air to operate safely and effectively.
De-icing your roof is a crucial aspect of winter home maintenance. By following these methods and safety precautions, you can effectively mitigate the risks associated with snow and ice buildup, ensuring the safety and integrity of your home during the winter months.
Remember, if you're unsure or uncomfortable performing roof de-icing yourself, it's always best to seek professional assistance to prevent any accidents or damage. Stay safe and proactive in maintaining your home during the winter season.