More of what tinner found

The underside of the decking in this house was damp. I don’t know what the age of the roof was, probably atleast 10 yrs. But, as you can see, no large granule loss. Water going right through.

Why do you think I Dutch-Lapped my roof? :mrgreen:

That is just insanity if you ask me.

looks like a nail in the water channel to me. that will do

Nope. The 2nd pic is same shingle on the other side. No hole. There were many shingles that looked like this. Coming through right at the keyway. Some of them had ice droplets on the back.

Do you know what brand of shingle that is?

No. Is there a way to tell other than if its marked on it somewhere? I still have the old roof in my trailer.

Is there any way the water was traveling under the shingles? That shingle does look sopping wet!!

Get used to it. They are very porous lately.
I pass up many shingles repairs every year. Of the darned few I take, 90% have water coming through normal looking shingles.

I have done many t/o jobs that the felt had water stains right in the key way.After shingles were off,you could see the lines where keys were.