Please take a look at these pictures and tell me what you see. Are the cracks lack of ventilation or a manufactures defect ? Roof was fairly new, ventilation was soffit, gable and a thermostatic controlled attic fan.
Pictures would help.
Ok, I see them now. ;)
Got you
They don’t appear that old, but judging with the algae stains in the background, the cracks look like they would most likely be a Manufacturers Defect.
:)
It would appear that the horizontal cracking is following the roof decking seams. Ventilation problems may be causing this due to excessive thermal cycles in the attic. Those cracks may already be leaking a bit and should be looked at by a roofer.
I don’t see the roof deck seams in those photos.
I am open for further advise.
Your joking right? Not to be harsh Brad but you may want to look at those pics again.
I see one cracked shingle in your pictures. I really wouldn’t consider that a crack to begin with. It was probably done during install or came in the bundle.
How old was the home?
OSB or plywood
Did the vent fan work?
Were the soffit vents open?
From your pictures I see nothing wrong with the shingles. DO you have more pictures of actual crack?
BTW its not going to be anew roof if its stained.
Both Pictures 2 and 3 are showing horizontal cracks Sean.
Just make you wonder if it were not a defect.
I never damaged a shingle like that during installation.
I dont see it. I see 1 shingle with a visible crack but that it. Must be playing with myself too much. Blindness setting in. 
Well, I’ll admit it, I had to put my glasses on. 
Now that I squinted I can see them.
How many were there? A few wouldn’t bother me, every other one may be a manufacturers issue.
That crack is about 4 or 5 feet long. The only thing that would cause that is the roof deck moving and the shingles not. It may be a defect in the shingle that doesn’t allow it to flex enough but, who knows. I would defer to a roofer anyway.
I Warned you over and over Sean you will go blind
LOL. Wonder what the cause is.
Ah, I mean the crack. ;)
Roof was new with a plywood deck. House was built in the 80’s. Soffits were open and fan did work. I know pictures are lacking, but shingles had several cracks that were only on the east side. This is a first, especially on a new roof. This leads me to believe it was during installation on a manufactures defect. That’s why I have called it out and requested a roofer
Probably smart to have a roofer look at it. Even if it costs them $50-$75, better that than the consequence of this getting worse over time and requiring a patch
looks like it may be a problem with the sheathing moving, did you check out the attic?
There’s really only one photo that’s any good. It’s not enough to offer an accurate opinion on.