Mold On Roof Shingles ?

It's MOSS. Put some zinc sheet neer the top of the roof - the zinc ions work pretty well at killing moss. So does copper sulphate solution. Lots of commercial preps too - but most tend to stain anything they touch.

Why do you say that moss is an indicator ofa failing roof?

Once you begin to see that green stuff on your roof, that's an indicator it's time for a new roof. Replace it before winter or you will have leaks.

It is just a sign that the roof is staying damp and has organic material exposed. CAN be due to a deteriorated roof - but also can be due to being too well shaded with trees close by that have moss on THEM.

Moss is an indicator that a roofs going to fail at some point. The shingles keep lifting up as it grows.

Greg

ALL roofs will fail at some point.

up till a number of years ago no roof around pittsburgh had that wierd discoloration, now every roof does that faces north. something big must of changed.

if you believe every roof needs replaced the shingle companies will be thrilled, at least around western pa its every home except those with metal roofs

theres a company that advertises they clean roofs, i dont know what they use but was told not to use bleach

It did. The makeup of the shingles changed. I think it was copper, but could have been something else that was added to the shingles to keep the moss and mold down. In order to make them cheaper , that was left out of the shingles, or greatly reduced.

I have seen it mentioned that if you take a copper wire and weave it in the shingles about every 4 or 5 rows, it will help.

My garage keeps getting blacker. The green moss that built up on my two sheds, lifting the shingles, gets to a half inch thick. Those are both under trees with complete shading.

Greg

I'm pretty sure zinc will work but not copper.

Greg?

Where do you live, I've never seen moss on a roof that thick, only on the north side of trees in a deep forest.

Undisturbed the moss makes a half decent roof - - -

Pittsburgh. I've seen it before on other houses sheds. My home sheds roof was going bad before I moved in 7 years ago. There are holes in the roof now, and walls. Been waiting to get tore down. Pine limbs also rest on top of roof adding to problem.

Greg

I've seen an inch on cedar shake roofs. Next to blue spruce trees or pine that totally shaded the roof. Can't remember which side - but damp because right down by the swamp