If you have lived through a Colorado or Wyoming hailstorm, you already know hail does not play fair. One storm can leave your neighbor with a totaled roof while yours looks untouched. The size of the hail is the biggest factor, but it is not the only one. Here is a practical breakdown of what different hail sizes tend to do to a roof, and why two roofs on the same block can come out so differently.
Before we get into sizes, three things matter almost as much as the diameter of the stone:
Keep those in mind as we walk through the sizes.
At this size, solid ice and wind driven hail can cause damage, especially on older roofs. This used to be a point of debate, but recent research from the Insurance Institute for Business and Home Safety found that even sub severe hail under one inch can speed up the aging of asphalt shingles and knock loose granules, leaving the roof more vulnerable to the next storm. Asphalt shingle roofs in the ten to twenty year range are the most at risk. The damage is not always obvious right away and may take time to show, but it is real. Newer impact rated shingles often shrug this off, though heavy, fast moving ice can still leave marks. If your hail was the soft white kind that exploded on contact, your roof likely came through fine.
This is the size where damage really ramps up. One inch hail is the National Weather Service threshold for a severe thunderstorm, and that line was drawn because hail damage increases sharply at this point. Expect hail hits across the majority of aging asphalt roofs. Other materials hold up better:
Now we are in serious territory. Solid ice at an inch and a half can damage the large majority of roofs out there. For reference, the impact resistant shingle testing done by IBHS uses lab made hailstones in the one and a half to two inch range, which tells you how punishing this size is.
At two inches you also start seeing heavy collateral damage beyond the roof, including broken windows and dented siding.
At this size, almost everything is on the table for replacement.
For perspective, baseball sized hail measures about 2.75 inches, and anything in the four inch range is softball sized. Colorado has seen exactly that. The May 8, 2017 storm that hit the west Denver metro produced hail ranging from baseballs to softballs, broke through the roof of the Colorado Mills mall in Lakewood, and flooded the building with several inches of water. That storm caused an estimated 2.3 billion dollars in damage and remains the costliest catastrophe in Colorado history. In Wheat Ridge alone, city officials estimated that about half of all homeowners had roof damage.
Your roof is not the only thing exposed. Two inch and larger hail commonly damages vinyl siding, cedar and wood siding, and LP siding, which may need to be replaced, repainted, or restained. Fiber cement products like James Hardie tend to hold up best. Gutters, downspouts, and skylights are often part of the same claim, so it is worth having the whole exterior looked at after a major storm.
The same storm that barely marks a two year old roof can total a twenty year old one. As shingles age, they lose granules and grow brittle, so they bruise and crack far more easily. IBHS research found that weathered shingles that had already taken smaller impacts were roughly ten times more susceptible to damage in a later severe hail event. If your roof is in that ten to twenty year window, treat even a moderate hailstorm as a reason to get an inspection.
Hail damage is often invisible from the ground, and waiting can let small problems turn into leaks. If a storm has rolled through your area in Colorado or Wyoming, the safest move is a professional inspection.
At Excel Roofing, we have been helping homeowners across the Denver metro, Colorado Springs, Casper, and Sheridan since 1993. We will tell you straight whether you have damage worth filing on, and you do not pay a cent until you are content.