Roof shingles are exposed to a lot of wear and tear as extreme heat sun wind and precipitation come into contact with them.
Why does the roof have dark stain.
Three years ago i had a new fiberglass asphalt shingle roof installed.
The algae feed on the limestone in shingles.
It was the same color as my old roof a light tan.
But now this black algae is termed a roof shingle algae because of the annoying discoloration on a asphalt shingle roof.
Roof discoloration stain diagnosis cure prevention advice for trimming trees away from buildings.
I ve got a problem.
It is not uncommon for roof shingles to turn black over time.
Roofing manufacturers have tackled the problem of roof algae by creating shingles containing copper which is deadly to algae.
While the dark streaks are unsightly experts tell our team that the greatest danger to the roof is from moisture retention or root damage that algae and other life forms can cause.
Light spots on roof shingles dark colored asphalt shingles may appear lighter and patchy as they age.
Replacing the shingles on your roof just because you have black stains is not necessary however and you should be suspicious of any roofer that suggests roof shingle replacement as the only solution to your algae problem.
Once stains redevelope and stay then it s time to recoat the entire roof since this dark algae can develope anywhere upon it.
Stains on roofs have a variety of causes but noticing the stain color its location and the relation of he roof stain color and location to roof components such as chimneys flashings and the stain relation to roof conditions pitch shading nearby trees debris roofing materials will.
As the blue green algae accumulate they develop a dark hardened outer coating which results in the black stains you see.
When that happens it is generally caused by mildew algae mold or dirt stains.
Also algae and fungus can grow together to form lichen the roots of which can wrap around and feed on the granules covering the shingles.
Alan carson a home inspection educator and researcher points out that on cathedral ceilings where we see dark streaks following exterior studs or roof joists on cathedral ceilings very often this is often associated with condensation on the wall or ceiling surface and dirt in the air sticking to the condensation.
Water stains if the discoloration seems to be damp check the attic or ceiling below the roof stain and investigate for a leak.
This job goes much faster if you can borrow or rent a 12 volt diaphram garden sprayer with a large tank and a slew of hose preferably on a reel be sure to wear rubber boots plus gloves and stay upwind while applying the solution.
Look in the gutters for signs of asphalt granules that have washed off and expect to need a replacement.