Could be one of two things. One of them you are right about. The sun will kill these shingles after a few years. My gues is that this roof would be about 10-12 years old.
The other possibility is defective shingles. If the roof is newer this may be the case. It is possible that there were two different lots of shingles used on the home. However, I am betting on the sun.
The west and south sides of the house will always get much more sun exposure than the other two.
I’ve seen houses that had new roofs installed in cooler temperatures and in the hot summer, the shingles started to have problems with temperature expansion. Putting on a new roof isn’t as easy as it sounds.
I have seen this happen on new roofs when the shingles were installed in very cold temps.often times when summer sun and heat gets to them they will go ahead and lay down. We have also seen defective shigles do this and they will break off easy,and catch in the wind ect.Sometimes old bundles of shigles will be mixed into the new bundles when deliverd.We always check before unloading.One bad bundle can cause terrible grief for the roofer and the homewowner.
Check out www.airvent.com, you will find formulas to determine what the necessary ventilation would be for this home. I am concerned about your statement that there are 2 turbines and 2 gable end vents, this is not a very balanced system and is prone to short circuiting. I too am curious about the dormer, is the space the dormer serves a finished space or open attic? If it is finished then I ask how is the attic ventilation system you detailed supposed to serve the area. If it is unfinished then you likely have a dead air problem, the air is entering the gable end vent and going straight out the nearest turbine.
The ideal attic/roof ventilation system will wash the underside of the roof from eave to peak with cool air, just as rain water flows the opposite direction on the top side of the roof.
Look at air as a lazy entity, it seeks the easiest path to get back out of the attic once it comes into the attic through its inlet area. However the air that is just sitting around in places here and there is likely to continue to do so.
Be wary of obstructions that may be in the attics that can block the flow of air in an attic. I have experienced situations where the boxes of ‘sh…tuff’ was piled so high the attic could not vent correctly.
Look closely too at the flashing at the bottom corner of the dormer, I would have fired an employee that installed this way. The method used allows for a direct entry point for water providing that there is not any other flashing that is out of site under the shingles (I doubt that there is), this is a common mistake made by people that install roofing and siding and the reason for most of the leaks I repair at the corners of dormers and chimneys.
I’m new to this… in my second year of inspecting. My questions is, is there any way of telling how much life is left on a curled shingle like this? Does it rob the shingle of its life expectancy?
