Half bad roof

[Joshua L. Frederick]

This was a gable and/or Cape Cod style home with dimensional shingles. Half of the structure had vaulted ceiling and the other half had kneewall attics w/reg. ceiling. All vented into upper attic that had gable vents on either side. So, in other words, ventilation was in place. As you can see in the pics the entire bottom section of the west facing half is shot. Any idea on why this is occuring?? Had me baffled, to say the least. Any helpful insight is always appreciated!

[Bill Smith]

Are the deteriorated shingles over the kneewall attic?

[Joshua L. Frederick]

Originally Posted by bsmith

Are the deteriorated shingles over the kneewall attic?

Yes. They're also over the cathedral ceiling.

[Michael Roberson]

My guess: (judging from the pictures only) The roof was partially replaced, or repaired at different times. Those are new-looking and very worn looking shingles, at opposing ends of potential lifespan. If vents are in place, and eliminating the obvious, what you have is a " roof in varying stages of deterioration." There is an outside chance that these shingles are defective, but the end result is the same.

[Joshua L. Frederick]

Originally Posted by mroberson

My guess: (judging from the pictures only) The roof was partially replaced, or repaired at different times. Those are new-looking and very worn looking shingles, at opposing ends of potential lifespan. If vents are in place, and eliminating the obvious, what you have is a " roof in varying stages of deterioration." There is an outside chance that these shingles are defective, but the end result is the same.

Thanks for the input.
I'm almost certain that the other shingles were the same dimensional shingles. The others were definitely older with common wear/deterioration.

[James E. Braun, CMI]

Lack of proper venting.

[ROBERT V. YOUNG]

I tend to agree with Mr. Roberson. Partial roof.
I have seen this before and maybe can drive for 10 minutes in western section off island and see it again.
Did you try to look at nails on both for coloration, measure size for difference, look at starter for it should be in good shape if it was installed at the same time.
The drip edge on damaged area as compared to undamaged area, and so on.
I am just asking questions that I asked all my life when roofing for I did a lot of repairs and trouble shoting for companies.

[mthomas2]

Robert,

Thanks for that post. I had never thought to check the starter... Duh.

[mthomas2]

However... both sections of roof have the same shingle application pattern....

[Frank Albert]

That's an odd one, for sure. Defective shingles is a possibility, but it's too uniform for that. Some of the defective ones would be elsewhere too. Are you sure the ventilation isn't short circuited at the 'juncture'?
1/2 the side done at a different time is a real possibility too.

[Kenton H. Shepard, CMI]

Partial re-roof, possibly due to poor venting, poor thinking or low bank account

[ROBERT V. YOUNG]

Originally Posted by kshepard

Partial re-roof, possibly due to poor venting, poor thinking or low bank account

I am with you on this one Mr. Shepard.
They all play a relevance to this roofing job.