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Here we discuss debris on building roofs as a source of stains and roof damage. This article series tells readers how to identify & explain the most-common causes of black, brown, red, gray, green, or white stains appearing on roof shingles and on other building surfaces. Roof shingle stains are often caused by black algae, bleed-through or extractive bleeding of asphalt, dirt, soot, or organic debris.

See Causes of Roof Stains and  Catalog of All Roof Stains for the causes and types of stains that occur on building roofs. There are other sources of roof staining, from cosmetic to harmful to the roof. For the diagnosis and cure of other building stains, see STAIN DIAGNOSIS on Building Exteriors and STAIN DIAGNOSIS on Indoor Surfaces.

© Copyright 2010 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

ROOF DEBRIS STAINING - Black & Brown Debris Stains on Asphalt Shingle Roofs

Debris staining on roofs produces fairly uniform black or brown staining in areas where due to low-slope or presence of overhanging trees, leaves, or organic debris collects on the roof slope.

Decaying debris may encourage fungal or algal growth (cited above).

Lichens or even thick moss may also grow on such roof areas. Debris, lichens, or moss on a roof will shorten its life by holding water on the roof surface, preventing drying, and (in cold climates) adding wear and tear on the roof surface by freeze-thaw cycling.

In contrast, debris from an upper roof gutter that spills onto lower roof slopes may result in tan, white, or other stains depending on the metal of the gutter and the length of time that leaves and debris rest in it. (Photo at left).

The decision to permit the upper roof gutter to spill down the lower slope also risks creating an early wear-area and thus leaks on the lower slope roof.

Remedies for black or brown or gray debris staining on asphalt shingles: As cited above, cleaning off debris (gentle sweeping or washing, watch out for damaging the roof during cleaning), or cutting unnecessary overhanging tree branches may help.

See Proximate cause roof shingle stains and also see ALGAE, FUNGUS, LICHENS, MOSS on SHINGLES for details about these growths on buildings.

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ASPHALT ROOF SHINGLES
  ASPHALT SHINGLE DEFINITIONS
  ASPHALT SHINGLE FAILURE TYPES
  ALGAE, FUNGUS, LICHENS, MOSS COMPARED
  ALGAE STAINS ON ASPHALT ROOF SHINGLES
  ALGAE STAIN TEST METHODS
  ALGAE, FUNGUS, LICHENS, MOSS on SHINGLES
  BLACK STAIN REMOVAL & PREVENTION
  BLISTERS on ASPHALT SHINGLES
  CRACKS in FIBERGLASS SHINGLES
  CUPPING ASPHALT SHINGLES
  CURLING ASPHALT SHINGLES
  FISHMOUTHING ASPHALT SHINGLES
  GRANULE LOSS from SHINGLES
  HAIL DAMAGED SHINGLES
  LADDERING & STAIR STEPPING SHINGLES
  LIFE / WEAR FACTORS in SHINGLES
  MECHANICAL DAMAGE of SHINGLES
  MOSS & LICHENS on SHINGLES
  ORGANIC FELT SHINGLE DEFECTS
  SPLICE DEFECTS on ASPHALT SHINGLES
  STAINS on ROOF SHINGLES
  WHAT ARE ASPHALT SHINGLES
BUILT UP ROOFS
CERTIFICATIONS for ROOFING CONTRACTORS
CHIMNEY INSPECTION & REPAIRS
CHOOSING A ROOFING CONTRACTOR
CLAY TILE ROOFING
FIRE RETARDANT PLYWOOD
LOW SLOPE ROOFING MATERIALS
MEMBRANE ROOFS
METAL ROOFING TYPES
MODIFIED BITUMEN ROOFING
ROOF INSPECTION SAFETY & LIMITS
ROOF VENTILATION SPECIFICATIONS
ROOF VENTING ENERGY SAVING DETAILS
SLATE ROOF INSPECTION & REPAIR
SOD ROOFING
SIDING WOOD
STAIN DIAGNOSIS on Building Exteriors
STAIN DIAGNOSIS on Roofs
  Causes of Roof Stains
  Catalog of All Roof Stains
  Catalog of Black Roof Stains
  Black Algae
  ALGAE STAIN TEST METHODS
  Black Stain Removal & Prevention
  Bleed-Through
  Chimney-Caused Roof Stains
  Debris Staining on Roofs
  Lichens on Roofs
  Moss on Roofs
  Rust Stains on Shingles
  Soot Staining

• 7/07: thanks to Roger Hankey & Cheryll Brown, ASHI home inspectors in Minnesota, for the rooftop soot staining photograph. Mr. Hankey is a past chairman of the ASHI Technical Committee, serves as co-chairmain of ASHI legislative committee, and has served in other ASHI professional and leadership roles.

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More Information on Building Diagnostic Inspections and Repairs

• Roofing
• ASPHALT ROOF SHINGLES

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