Membrane roofing systems, especially TPO and PVC, are some of the most slippery roof coverings out there. They can be somewhat slippery throughout the year with water and rain, but they are particularly slippery when it snows. With the right temperature outside, if you slip on a moderately sloped flat roof (4/12 pitch or less), it can be almost impossible to stop sliding.
This can be surprising and unexpected when many owners of flat roofs may assume that because the roof is mostly flat, it is safer to walk on in the winter. However, even when a roof is completely flat, there is zero friction between your shoes and the membrane below. One wrong step can result in serious injury or death.
Safely Accessing a Flat Roof
If you feel that there is a definite need to get on your roof, it is important that you take every possible safety precaution. I want to emphasize again that even if you do take each of these precautions, it is still not entirely safe to venture onto your roof in the winter. There are too many things that could go wrong or be overlooked.
When setting up the ladder, an extension ladder is much safer than a step ladder. The rungs of the ladder need to extend 3′ above the eave line and should be secured with a rope to the gutter or close pipe, etc before climbing from the ladder onto the roof. This should be done tight enough to keep the ladder from sliding to the side when getting on and off the ladder. Never step on a rung that is higher than the eave line as this could push the bottom of the ladder out and cause it to slide.
First, plant the ladder firmly, on a flat surface, and somewhere where there is no snow or ice. An extension ladder is much safer than a step ladder. The rungs of the ladder need to extend 3′ above the eave line. Check the rungs for ice. A slippery step could cause a fall before you even reach your roof. Place the base of the ladder a distance from the vertical wall equal to one-fourth the working length of the ladder. For example, if your roof will connect with your ladder 16 feet off of the ground, place the bottom of the ladder 4 feet away from the side of the house or building.
Clean and dry your boots from snow before you climb onto the ladder. The typical rule of thumb is the ‘3 point rule’. Essentially, it is important to keep at least three points of contact with the ladder at all times. Two feet and one hand or two hands and one foot are both acceptable positions to take as you ascend the ladder.
Stop when your head is about 2 feet above the line of the roof, so that you can easily reach down and touch the roof. If there is snow on the roof, it is essential to thoroughly remove the snow. A metal snow shovel or hammer to break the ice will damage the membrane. Instead, use a plastic bladed shovel. Remove the snow as thoroughly as you can safely remove it from the point of the ladder.
While removing the snow, keep the core of your body inside the ladder rails. Do not lean to the side so that you are hanging outside the rails, this could lead to a serious fall. Instead, move the ladder if you need to reach to the side.
Your ladder should be secured with a rope to the gutter or a close pipe before climbing from the ladder onto the roof. This should be done tight enough to keep the ladder from sliding to the side when getting on and off the ladder. Never step on a rung that is higher than the eave line as this could push the bottom of the ladder out and cause it to slide.
If there is a layer of ice on the roof, you may want to use some salt to deice the membrane. If there is no layer of ice, take a towel and wipe off the area you will be stepping on. You need to thoroughly dry the area, so that it is no longer slippery to the touch. Once it is completely dry, you can carefully climb on.
Repeat this process, removing snow and ice and drying the area you will walk on with a towel. Be very aware of where you are standing. Do not step anywhere where there is any snow. Do not think that you will be able to keep your balance if you step on the snow, it is incredibly slick and you can easily fall.
Other Safety Measures
Even if the membrane was not as slippery to walk on, you still would need to remove the snow to reveal any possible hazards as you are walking across the roof. For example, a layer of snow can easily conceal a skylight or other opening. If someone stepped in this area, they could fall through the roof. There are also gas pipes and other tripping hazards throughout the roof. In order to properly avoid these, and a serious accident, all snow must be removed.
In the interest of your roof, it is important to remember not treat your roof the same you would treat your driveway. For instance, do not wear cleated shoes on your roof to help improve traction; the shoes will cause puncture holes in the membrane. Hacking at snow and ice could also cause problems. Only use a plastic bladed shovel and salt to remove snow and ice.
Safely Hanging Christmas Lights
If you are looking to get on your roof to hang Christmas lights, try hanging them from a ladder instead. We recommend home depots instructional safety video below. Remember to move your ladder often as you are hanging your lights.
In the end, it is not worth the risk to climb up onto your flat roof in the winter. Calling a professional will be a responsible, safe choice that will still fix whatever problem you may have. If you are worried about spending the money, just remember that any fee a professional would charge to remove snow will cost less than a hospital bill.