Interesting

I took some pix of a roof I did years back to show the asphalt melting. The pix were taken in June, last year. There were no other issues with the roof. Shingles were still sealed down, none missing, etc.

Same roof after somebody just pressured washed the house. There had been a recent paint job done. Paint is missing from metal on the mansard area, and chimney up above. One corner flashing lifted, Shingle torn loose, window screen destroyed though the pic isn't too good. Washer company says they didn't do it. :blink:

Not sure if you can tell it, but almost all the 'saw-teeth' are now unstuck. What do you think?

Those are Elks. The asphalt is from the sealer strip, not where the tabs are. I also found out that even though she saw the damage when it happened, she procrastinated, then called me, then called them. They did it 6 months ago. I'll just patch it up myself for free and renail the shingles they blew loose.

So was it chemicals from the pressure washing that caused the tar runs?

If they were tabbed for the pitch I would suspect the tabbing material because it looks like what I've seen running out from under a few concrete tile ridges I've repaired where the original contractor used an oily mastic. Aside from that I would suspect spot defects in the seal material which is somehow not in contact with the underlaying shingle. Not sure really. Did you have the opportunity to peel one up and inspect it?

I run into the saw teeth unstuck all the time but I can't say i recall seeing the adhesive melt and run down like that on a shingle roof before.

Seen plenty of tar runs oozing out of rolled rubber roofs but never shinlges.

Of course the steep mansard slope played its role in it but its got to be a defective shingle right?

What kind of shingle did you install?