Wood Roofing: Separating Cosmetic Damage from Performance-Reducing Damage

High winds, epic blizzards, pounding rain, and hailstorms make Colorado’s weather conditions unique and hard-hitting for homeowners and insurance claim adjusters alike.

Pie’s Dustin Smoot RRC, RRO, LEED AP, an expert in roof damage assessment, shares his roof performance expertise in Wood Roofing: Separating Cosmetic Damage From Performance-Reducing Damage, published in the March 2012 edition of PLRB.

Wood shingles and shakes comprise a small, but significant, portion of the steep-sloped roofing market.  These wood roofing products seem to show up in more and more hail claims. The big question is:  What is performance-reducing damage and what is simply cosmetic damage?  There is a lot of mystery behind the actual determination of hail damage on these types of roof systems.  Let’s first differentiate between cosmetic versus performance-reducing damage.

Properties of Wood Roofing:

In general, wood roofing becomes very fragile as it ages due to normal seasonal weather and exposure to ultraviolet (UV) radiation. Some types of wood roofing materials are more fragile than others.  Longevity and physical properties of wood roofs vary between species of wood and even within a species, depending on the age of the lumber when it was harvested.  Foot fall splits and broken ridge shingles are very common deficiencies found on wood roofing.  It can be very difficult to differentiate between hail impact damage and foot fall splits.


Breaking Storm damage into (2) Two Categories:

1. Cosmetic damage comes in the form of dents in lighter gauge metal and spatter marks on the roof shingles/shakes.  Although these two conditions would not be considered performance-reducing damage, the observation of this “collateral damage” indicates the roof has experienced a hail event which could have damaged the roof.  This typically does not call for the replacement of the items unless the damage is to the extent that it becomes performance reducing.

2. Performance-reducing damage comes in the form of a hail strike which is directly over a fresh split, or adjacent to a fresh split where the hail struck an unsupported section of the shingle/shakes. If the shake is new and still retains much of its original thickness, it would typically take hail over 2-inches in size to cause a split.  Badly weathered shakes can split and crack with 0.75-inch hail.  This situation may call for the replacement of the roof cover.

Inspection/Evaluation Tips:

  • Before determining the extent of the storm damage, observe the condition of the roof beyond any storm damage including quality of shingle, age, installation defects, etc.
  • Wood roofs drain in a different way than do asphalt shingle roofs.  While rain on an asphalt shingle roof flows off as a sheet of water, on a wood roof (particularly shakes) the water finds the path of least resistance causing some of the shakes to be exposed to more water than others.  This causes premature erosion to a wood product in certain areas which can sometimes give the appearance of hail damage.  Although this natural weathering is not related to a single storm event, it can make a roof more susceptible to damage by hail or wind, and could cause damage which can be misinterpreted as storm damage.

Read the full story here .

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