The shingles are sliding down the roof because they are high nailed. The nails are supposed to go through a strike zone in the center of the shingle. All of these nails are about 2 to 3″ above that strike zone.

 In this picture, you can see how the shingles are high-nailed. Below the nail holes, there are red dots that represent where the nails should be.

These pictures don’t need much explanation. The chimney is genuinely about to fall off the roof. The mortar is falling out all over, and the bricks have massive gaps between each other. One good push, and this entire chimney would fall off the roof!

As you can see, the roofer chose to put this roof on used shingles instead of metal flashing to flash the chimney. This allows water to get in all around the chimney!