Shingle pitting

I have seen shingle pitting on roofs that have no attic ventilation at all and it appeared that the excessive temperatures in the attic have contributed to these pitt marks. However this picture came from a roof that had soffit ventilation around the perimeter and turbines on top. Any ideas? Also most of the shingles were tearing.

Turbines are crap in my area. When there are soffit vents installed, they need ridge vents for proper ventilation.

These shingles are simply failing. Write it up as such.

Do you think this is a two fold problem? Pitting due to lack of proper ventilation and then cracking shingles due to age or defect?

BI do quite a bit of roofing inspections for both insurance companies and private parties… I always consider the following when I inspect a roof;

  1. type of roof
  2. age of roof
  3. are there multiple layers
  4. type of attic ventilation and is it adequate
  5. are anomalies isolated or widespread
  6. any information about the wx conditions when they were installed
  7. manufacture information (this can be found on the shingles but would require removal of same)

Blistering usually is the result of either 1.) manufacturer defect 2.) trapped moisture between shingle layer working its way out creating a pit or small pot mark 3.) installing shingles over wet tarp paper and/or shingles themselves being wet when installed…again the trapped moisture is working its way out 4.) improper ventilation can be attributable to a certain degree but then again its trapped moisture/gas working its way out; when its a ventilation issues it is often widespread.
Let me also say that just because shingles are showing blistering does not necessarily mean that their service life is affected hence replacement may not be necessary.

Splitting often occurs either from age or at times from thermal expansion and contraction.
Trying to discern the source of the problem requires one to carefully annotate the age of the shingles which areas are affected in relation to the directional slopes, ventilation of attic and at times manufacturer information all of which can be technically exhaustive.

Depending on the age of the shingles I will either put that the shingles have reached their service life (older shingles) or simply note my findings and comment if such findings affect
the water shedding ability of the shingles or if the manufacturers service life is affected.

Finally let me say that calling for further investigation by a roofing contractor may not yield anything for your client…many roofers are simply installers with limited understanding as to how and why shingles fail… its easier for them to simply call for roof replacement which of which in many cases is not necessary. If possible try to determine the manufacturer and recommend that one of their reps inspect same.

Hope that helps…


Lots of good info. Thanks for the help.

This kind of pitting is really blistering caused by poor ventilation. It typically happens within the first few years after installation and is more common on older roofs.

To be specific, it’s caused by volatiles… parts of the asphalt that are easily evaporated… flashing out of the shingle due to overheating from poor ventilation.

Anyone ever seen bird damage?