If your roof is old, walking on your roof can actually cause more damage than it is worth. We’ll tell you why as well as when it is appropriate.
To understand why walking on an asphalt shingle roof can cause damage you have to first understand the anatomy of a shingle. The main element that you need to be concerned about is that middle layer which is asphalt. Asphalt is that part of a shingle that allows the water to shed off of a roof and keeps you dry. When that middle layer becomes dry, it becomes brittle. With the average asphalt roof life being only 18-20 years, you want to extend the life of your shingle as long as possible.
Brittle asphalt is more likely to crack
When a shingle dries out, more especially in the last 5 years of a roof, the shingle becomes less pliable. When that happens, small cracks occur. They may not even be visible to the human eye. These micro-fractures get small amounts of water in them. When water freezes, it pushes those cracks further apart and each freeze-thaw event pushes even further apart. This can happen dozens of times in a typical Wisconsin winter. That’s why so many people look at their roofs in the spring and wonder how it got so bad, so fast.
The decking of your roof is made out of wood in most cases. The wood tends to remain strong, more especially if your shingles had good underlayments under them. Good decking will also remain somewhat flexible. But the shingles, well that’s another story. The older a shingle gets, the more brittle it becomes.
Like Walking on Potato Chips
Once the asphalt becomes dry and brittle, it can crack. The weight of a person causes the wood decking to slightly flex and that’s ok. What is not ok is that a dry, brittle shingle on top of that decking is not going to flex the same. While some roofers will insist on walking on a roof as part of their sales process, your risk of cracking goes up exponentially the closer your roof gets to that 20 year mark. If the only thing protecting your family is a shingle the consistency of a potato chip, you may want to think twice before allowing a salesman to walk it. Even a good Doctor knows the first rule of medicine is “first do no harm”. Your roofer should follow the same advice.
How can I make my roof last longer?
Good ventilation, which includes both intake and exhaust ventilation, can extend the life of a shingle. The cooler you keep it, the longer it will last. Tree shade can also extend the life of a roof. But caution should be followed when planting trees because if branches fall on your roof they can damage your roof and tree roots can cause damage to your basement foundation. Trees that overhang houses may extend the life of a shingle and even make your house more comfortable in the summer, but you have to weigh your risk tolerance. There’s nothing worse than waking up in the middle of the night to a tree limb crashing into your house during a storm.