Roof Defect?

I often come across roof coverings which appear wavy, and sometimes with lifted edges. I’m not sure what the cause of this is. Is it a poor installation? Caused by being a multiple layer? Manufacturers defect? Sheathing issue?

Any help from anyone with knowledge or experience with this would be helpful. Thanks.

Is it installed over shake shingles?

No, it doesn’t appear to be.

My guess is there is multiple layers, I see this allot under shakes. The cost involved in stripping a multi layer roof plus shakes, and a re sheet is a bit higher that a shingle over. I would recommend a further investigation.

It looks like the roofer also installed the siding. :smiley:

multiple layers, what did u see in the attic?

I agree ,multiple layers most likely, and that sure is a big bird at the upper window.
Maybe he is trying to pick up the tabs for nesting material.:slight_smile:

Multiple layers.

What’s out of level… the soffit or the siding?


Next time you are doing an inspection and you see this, bring along a torpedo level.
Here is what I have noticed in my years roofing and applying siding.
You have an untrained gang ,mostly 2 guys to do a job and they do not know how to chalk lines to follow the courses as they move up a side.
There is a gabled roof garage and they get no horizontal reference.
They have no reference start. They start with a line level or worse a 4 foot level and do not adjust the courses of siding every 7 to 10 courses up.
By the time they get to the roof they can not adjust there line.
Its the sidding that is out of level. To me.
Put a torpedo level in your kit. 8 to 10 dollars.

No attic space, which raised my question even more knowing that there is not enough ventilation to prevent the sheathing below from rotting.

John,it is easy to see how many roofs are there by looking under the starter course or going to the side of the roof if its not a hip style roof and again looking under the shingles for the layers.
To me its a re-roof and a poor one but it is what it is.
There is a trick to applying shingles over shingles and not have that wavy affect and I will post it one day shortly.
Its slower and most roofers work by the square 10 by 10 square feet. They want to be as fast as they can be.
That is why you also see tin work being sealed with overlap joints instead of wrist lock jointing. Its faster.

Thank you. I did know it was a multi layered roof, I was just wondering if that was the underlying cause (no pun intended), and based on everything said here, it appears that it is.