What size hail causes roof damage?

On average, it takes a 1″ or above diameter hailstone to cause damage to common asphalt shingles. When referring to hail sizes, here are a few common objects to compare:

• Pea  = 1/4-inch in diameter
• Marble = 1/2-inch in diameter
• Dime or penny = 3/4-inch in diameter (hail the size of a penny or larger is considered severe)
• Nickel = 7/8-inch
• Quarter = 1 inch
• Golf Ball = 1½  inches
• Tennis Ball = 2½ inches
• Baseball = 2¾ inches
• Tea cup = 3 inches
• Softball = 4 inches

Several surveys and studies have been completed to show to damage potential of different size hail stones on various types of common roofing materials. Field observations and ice stone impact tests provide some common correlation between stone size and damage potential.

Material	Hailstone Size
3-Tab organic asphalt shingles	1″
3-Tab fiberglass asphalt shingles	1¼”
Cedar shingles	1¼”
Fiber-cement tiles	1¼”
Flat concrete tiles	1¼”
Heavy cedar shakes	1½”
30-year laminated shingles	1½”
Built-up gravel roofing	2″
S-shaped concrete tiles	2″