Mastering Roof Inspections: Hail Damage, Part 10

by Kenton Shepard and Nick Gromicko, CMI®



The purpose of the series “Mastering Roof Inspections” is to teach home inspectors, as well as insurance and roofing professionals, how to recognize proper and improper conditions while inspecting steep-slope, residential roofs. This series covers roof framing, roofing materials, the attic, and the conditions that affect the roofing materials and components, including wind and hail. 


Elevation Damage
Windows and Doors

Window screens can show streaking or damage from even relatively small or less dense hail.


Vinyl windows are vulnerable to hail damage, especially the sash and exterior bead.

Wood windows, doors and trim are sometimes clad with aluminum on the exterior.  This type of cladding, especially when it's used on horizontal surfaces, can show indentations and spatter marks from hail.

Fiberglass and vinyl windows may have cracked frames. Steel frame windows may have indentations and spatter marks, and, of course, all windows can have broken glass.

If hail carries enough impact-energy, it may break window panes.


Garage doors and trim are typically made of aluminum, and will show damage.

While looking for hail damage, you’re not limited to using your eyes. You can also feel for it. If the surface you’re examining is in the shade, it may be easier to feel damage than see it. It’s often easier to see a hit if you use the side of a piece of sidewalk chalk to color the area around it, although this will create the illusion of larger damage than actually exists.


Aluminum Siding

Aluminum siding is the type of siding most easily damaged by hail, with the damage appearing as indentations, as you can see in this photo. Soaking the siding with a hose will make the damage more apparent, so, if possible, spray it before you photograph it.

Also important to remember is that just because wetting the surface makes hail impressions easier to see doesn’t necessarily mean that the siding has suffered functional damage, such as fracturing, which allows moisture intrusion.

This damage was not caused entirely by hail. You can see spatter marks, but there is also more severe damage. Hail won’t leave damage which looks like a slice, and hail damage doesn’t appear as scratches.

Aluminum dryer vents will also show damage.

Spatter marks are areas where hail impact has removed oxidation from the surface. These marks will re-oxidize and fade over time.

Hail fall is random. It’s not likely to leave marks of identical size, equal distances apart, or on the same part of different shingles, as you see here.

Vinyl Siding

Vinyl siding is easily cracked and broken.  Large hail can leave spectacular damage. This neighborhood was hit by a storm that dropped hail in the size range of 1½-inch to 2½-inches.

Homes in surrounding neighborhoods had hardboard siding that showed only minor damage, such as chipped paint.

This storm left damage on downspouts, vinyl, wood and aluminum trim.

The entire neighborhood looked like it had been attacked by a battalion of teenagers with potato cannons. 

Wood siding can be cracked, dented and broken. Lapped wood siding is more easily damaged than wood panel siding. Lapped siding on older homes was often manufactured from redwood, which is a relatively soft wood that becomes brittle with age.

Is this wood, or a composite with wood-grain overlay? Lack of splintering in the indentation suggests a composite. You’ll sometimes need to look closely to make sure.
Paint may also be damaged if wood is indented. Again, look closely. This is a composite made to look like wood shingles. The lack of space between each shingle is the telltale sign.


Learn how to master a roof inspection from beginning to end by reading the entire InterNACHI series: Mastering Roof Inspections.

 Take InterNACHI’s free, online 
Roofing Inspection Course
Mastering Roof Inspections
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Inspecting Underlayment on Roofs
Fall-Arrest Systems
Roofing (consumer-targeted)
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