When I first looked at the roof, the shingle damage was puzzling, have never seen this particular damage. The question was answered as I proceeded with the inspection. Thought it would be interesting to ask for opinions as to what caused the unusual surface damage. Here we go!
moss that has been removed
Chicken pox…
It’s called blistering and often is a result of the manufacturing process, many manufacturers state that it is a cosmetic issues however my take is that depending on the severity, it does result in the mineral mat being exposed to solar rays which can and will deteriorate the longevity of the mat itself.
Another theory is that when shingles are applied wet or upon a wet substrate that moisture can wick into the shingles and as the shingles heat up (as well as improper venting techniques or lack thereof) can attribute to blistering.
Eitherway, its is not normal.
The granule coating on shingles not only offer aesthetic beauty but also are a fire retardant and a protective coating for the mineral fiber mat itself. Studies performed by companies such as Haag (producers of often incompetent hail damage specialist that whore themselves out to insurance companies) that state that loss of granules have little to no effect on shingles is laughable at best. There is a reason that manufactures put over a pound of granules on each shingle.
I would note the defect and direct them to contact the manufacturer about same, often if argued wisely, the manufacturer will have the shingles replaced versus getting bad publicity.
regards
Jeff
It is blistering, but only located in a section of the rear slope (gable roof). As I discovered in the attic, there was a house fire. About one half of the entire roof structure had been replaced, but not where the defective shingles are located. Half a-- repair?? 
That could explain the area of concern being localized and not the entire roof.
It is blistering and Mr. Haynes is correct in his opinion in my view.
Manufacturing defect. Kenton will know or Mr.Cyr,s in-depth indexing on roof shingles.
Yes you can do a specific area of the roof with new shingles as long as the match and the original shingles are not brittle, old, faded, etc. They must be pliable and easy to work with.
Remember that the shingle ages are different and the roof will only last as long as the original shingles.
It is a simple repair.
Blistering used to be a manufacturing defect, but now that everything is mixed by computer, it usually due to excessive heat, often from poor ventilation, and often happens in the first year or two after installation. A fire would do it though.
Over time the caps will erode away, exposing the mat.
There’s some disagreement about whether it will cause shingles to fail prematurely. The more widespread the blistering, the greater the chances that it will contribute to premature failure. Bear in mind that beneath each of theose shingles, there’s another shingle and that the amount of time it takes for UV to damage them enough to cause leaks, will probably be close to equal to the service life of the shingles anyway. The quality of the shingle enters into it too. The lower the shingle quality, the more likely it may be a problem.
That’s what I tell clients.
Probably 15-16 years or even lower!
That is a good point Brian.
I have witness shingles lasting 35 to 40 years.
I think home owners mostly change roofs because of several reasons.
1;Sold a job. Meaning that a home owners thinks its ten years as warranted on the singles package …Old word of mouth.
2: They see fading, again getting estimations and roofers tell the to redo.
3: Small leaks. Mostly around flashing and vents. It can be repaired at a small cost as compared to re-roof.
ETC.
Yes 16 years is a norm.
They are not doing the maintenance yearly.
