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Here is our catalog listing the types of black stains that are found on roofs, using asphalt shingle roofs as the prime example. 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.

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CATALOG OF BLACK ROOF STAINS - Aesthetic or Cosmetic Roofing Issues - Black Stains on Asphalt Shingles

BLEED THROUGH - Black Bleed-Through or Extractive Bleeding Black Stains on Asphalt Shingles

Extractive bleeding - bleed-through asphalt shingle stains may be mistaken for but are not black algae or black "fungus", nor are they soot. Extractive bleeding stains on asphalt shingles are caused by loss of black pigment in the asphalt mix intended to impregnate the shingle mat itself.

Extractive bleeding or "bleed through" stains leaving black streaks running down an asphalt shingle roof is an indication of a defective roofing product. Typically bleed-through on asphalt shingles appears as black streaks running down shingles. You'll see black streaks of varying length and width (photo at left). Please see Bleed-Through for our full discussion of extractive bleeding stains on asphalt shingles.

BLACK ALGAE - Black Algae Stains on Asphalt Shingles

Misnamed as "mildew" or "fungus" by some writers, algae staining on asphalt shingles usually in shaded areas or on the more-shaded roof slopes (photo at left) characterized by black staining fairly uniform over shingles, but appearing specifically in areas of the roof shaded by nearby trees. Please see  Black Algae for our full discussion of this topic. The black stains on the roof at above left are probably an algal growth.

DEBRIS STAINING - Black Debris Stains on Asphalt Shingle Roofs

SOOT STAINING - Black Soot Stains on Roof Shingles Around Chimneys

Soot from fireplace flues washing down onto the roof - characterized by staining appearing below and in line with the chimney Please see Chimney-Caused Roof Stains for the full article on this topic as well as some important fire and flue gas safety warnings. Photograph of a soot-stained roof top was provided courtesy of Roger Hankey a Minnesota home inspector.

List of Stains on Building Roofs, Surfaces, Walls

In the following guide we list types of stains by stain color & appearance, by building location or material, and by stain cause. We distinguish among the following stuff that may stain or be found growing building roofs, walls, or other surfaces, with extra focus on asphalt shingle roofs as well as other roofing materials such as wood shingles, wood shakes, roll roofing, and even slate or tile roofs. Some of these types of roof stains or discoloration are only cosmetic in nature, while others may indicate growths that are likely to reduce the roof covering life. A more detailed, illustrated version of the list below is given at Stain Diagnosis on Building Exteriors.

• Algae caused black stains on roof surfaces - Some photos of black algae stains are at Black Algae Stains on Asphalt Shingles. For details see ALGAE STAINS ON ASPHALT ROOF SHINGLES. Algae can produce black stains on asphalt roofing products. Also see  ALGAE, FUNGUS, LICHENS, MOSS COMPARED.
  
• Black stains on asphalt roofing products such as asphalt shingles or roll roofing, caused by extractive bleeding (product defects) - see Bleed-Through and see Roofing material defect / environmentally-caused roof shingle stains.
• Black, brown, or gray stains on roofing products due to debris left on the roof surface, such as piles of leaves and organic waste from nearby trees. See Debris Staining and see Proximate cause roof shingle stains
• Black or other colored stains on roof surfaces may be caused by soot from chimneys, both wood-fired and oil-fired devices. Black or other colored stains may also appear on roof surfaces from nearby industrial activities. See Soot Staining.
• Black stains on building interiors: such as on carpets, drywall, or trim: see STAIN DIAGNOSIS on Indoor Surfaces and then STAIN DIAGNOSIS on Indoor Surfaces and also see STAINS on Indoor Surfaces: PHOTO GUIDE
  
• Brown or red stains on roof surfaces are often caused by rust from wearing steel flashing or other on-roof metal products. See Rust Stains on Shingles.
• Chimney stains on roofs - see see SOOT STAINING - Black Soot Stains on Roof Shingles Around Chimneys and see Proximate cause roof shingle stains
• Debris stains on roof shingles - see Debris Staining - Black Debris Stains on Asphalt Shingle Roofs
• Extractive bleeding stains on asphalt roofs - see Bleed-Through and see Roofing material defect
• Lichens growing on roof surfaces - Lichens are not the same growths as moss or algae, and are difficult to remove without damaging the roof surface. See Lichens on Roofs for details about how lichens can cause roof damage, see ALGAE, FUNGUS, LICHENS, MOSS on SHINGLES for a guide to preventing these roof growths and stains. Also see   ALGAE, FUNGUS, LICHENS, MOSS COMPARED.
• Mold or fungus growing on roof surfaces or on other building surfaces - see ALGAE STAINS ON ASPHALT ROOF SHINGLES. See FIND MOLD in BUILDINGS, HOW TO for a guide to looking for mold contamination in or on buildings, and see WHAT MOLD LOOKS LIKE for a guide to just what mold looks like on building surfaces. Be sure also to see Stuff that is Mistaken for Mold to avoid becoming excited about harmless substances that people think are toxic mold. If you know your building has a mold problem, see ACTION GUIDE - WHAT TO DO ABOUT INDOOR MOLD.
• Moss on roof surfaces - see ALGAE, FUNGUS, LICHENS, MOSS on SHINGLES. Green or other colored mosses are a bit easier to remove than lichens on roofing surfaces, but both can carry away mineral granules and damage the roof surface. Moss tends to hold more water and moisture on the roof surface. So in our opinion moss is more likely to damage a roof surface than lichens or algae. Also see   ALGAE, FUNGUS, LICHENS, MOSS COMPARED.
  
• Rust Stains on buildings - see Rust Staining - Red or Brown Rust Stains (on shingles)
• Soot or Creosote black or brown stains on roof surfaces near or below chimneys - see SOOT STAINING - Black Soot Stains on Roof Shingles Around Chimneys and see Proximate cause roof shingle stains
• Tree-caused stains on roofs - see Proximate cause roof shingle stains
• White stains on roof surfaces may be from wash-down of pigments in paint on surfaces above the roof such as a gable end or dormer wall; white or less-black roof surfaces may also be found below copper or aluminum flashing whose salts run down the roof surface in wet weather, preventing algae or moss growth and leaving a white area on an otherwise stained roof surface. Our article at ALGAE, FUNGUS, LICHENS, MOSS on SHINGLES includes a photograph of this condition on a wood shingle roof.

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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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