Roof Algae Stain Identification & Cure
Tests, removal or prevention of black algae & other stains on roof surfaces
- ALGAE STAIN TEST METHODS - CONTENTS: How to test for black algae growth and stains on roof surfaces. Algae stains and black marks on asphalt roof shingles: causes, effects on roof life, cure & prevention. Types & photographs of organic felt asphalt roof shingle defects & failures
- POST a QUESTION or READ FAQs about
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
Identification, cure & prevention of algae stains on roof surfaces:
This article explains methods used to test for and confirm black roof stains due to algae or "black fungal growth" on roof shingles. We provide a list of type of stains and colors that appear on roof shingles and on other roofing materials.
Green links show where you are. © Copyright 2015 InspectApedia.com, All Rights Reserved.
Testing to Identify Roof Stain Material
Some roofing consultants, including Mr. Norman (above) assert that all of the black stains on asphalt shingle roofs are due to algae growth.
See ALGAE, FUNGUS, LICHENS, MOSS on SHINGLES
But we found some experts describing an occasional product defect that produces extractive bleeding in asphalt roofing materials. Extractive bleeding occurs in other building materials as well.
See EXTRACTIVE BLEEDING on SHINGLES for more on extractive bleeding;
To test black roof debris for a determination of whether the black stains are due to soot, algae, fungus, or asphalt bleed-through our forensic lab will accept tape samples for processing at no fee between April 2009 and June 2009.
Select a roof material testing laboratory or any forensic or biological test lab that can identify mold, algae, and particles.
Use the tape sampling procedure and mailing instructions found at TEST KITS for DUST, MOLD, PARTICLE TESTS to send off lab samples for testing. (No more than two samples per roof should be necessary. If pre-arranged by email, InspectApedia.com offers limited pro-bono roof stain sample analysis in our own forensic laboratory.)
Be sure to press your tape firmly into the black stain material.
Testing Black Roof Stain Material in the Forensic Lab
In our forensic laboratory (not on a roof itself) we prepare a microscope slide of black roof debris particles for direct examination at low and high magnification. Algae is identifiable by physical characteristics.
If the black material does not appear to be an organic structure we use a solvent on the microscope slide. Xylene or Hexane will cause asphalt products to bleed and stream on a microscope slide.
Our photos above show black stains on a roof and an initial lab photo of the black roof debris at 400x. Sample material from the stained area on this roof was prepared on a microscope slice and mounted in lactic acid. Lactic acid does not dissolve asphalt but that will hydrate and expand algae and mold spores. The debris in our photo (above left) looks like brownish black something that is not organic. But take a look at the photographs just below.
Here is what that same sample looks like under the microscope at 1000x, oil immersion, after allowing five minutes for hydration (expansion of the cells of material.) We see a dark algae on the left and green algae on the right, both found in the same sample material. The black stains on the roof above are definitely algae, not bituminous material.
Testing Black Roof Stains On the Roof
Mr. Norman proposes a simple test of applying a light spray of a diluted mixture of trisodium phosphate [use a TSP substitute, not TSP which is an environmental contaminant] and chlorine (with water) in the proper proportion will determine weather or not this is algae quite readily. If it is asphalt pigment, it will not lighten.
If the residue is bitumen, a petroleum product would be necessary to remove it, but cleaning the roof with any solvent would of course be unwise as you will also damage the shingles as well as risk a fire, explosion, and environmental contamination.
This website tells readers how to identify & explain the most-common asphalt roof shingle failures and
how to obtain asphalt roofing shingle failure claims assistance. These defects occur on organic-mat or fiberglass-mat
asphalt roof shingles.
Readers are also invited contribute roof failure information to the web author for research purposes.
web author for research purposes.
Continue reading at BLACK ROOF STAIN CAUSES or select a topic from the More Reading links shown below.
Or see STAINS on ROOFS for a complete catalog of roof stain sources & causes
Or see LIFE / WEAR FACTORS in SHINGLES
Suggested citation for this web page
ALGAE STAIN TEST METHODS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.
Green link shows where you are in this article series.
- AIR LEAK DETECTION TOOLS
- ALLERGEN TESTS for BUILDINGS
- ANIMAL ENTRY POINTS in BUILDINGS
- ANIMAL or URINE ODOR SOURCE DETECTION
- ANIMAL STAINS & MARKS in BUILDINGS
- ANIMAL or URINE ODOR REMOVAL
- BIOLOGICAL POLLUTANTS
- BLACK LIGHT & UV LIGHT USES
- CHIMNEY STAINS & LEAKS
- EFFLORESCENCE SALTS & WHITE DEPOSITS
- FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
- IAQ DIAGNOSIS via THERMAL TRACKING STAINS
- INSECT INFESTATION / DAMAGE
- MOISTURE CONTROL in BUILDINGS - home
- MOLD APPEARANCE - WHAT MOLD LOOKS LIKE
- MOLD CLEANUP GUIDE- HOW TO GET RID OF MOLD
- OZONE HAZARDS
- OZONE MOLD / ODOR TREATMENT WARNINGS
- PAINT FALURE, DIAGNOSIS, CURE, PREVENTION
- PAINT & STAIN GUIDE, EXTERIOR
- SIDING TYPES, INSTALLATION, DEFECTS
- STAINS on & in BUILDINGS, CAUSES & CURES - home
- STAIN & BIODETERIORATION AGENT CATALOG
- STAIN DIAGNOSIS on BUILDING EXTERIORS
- STAIN DIAGNOSIS on BUILDING INTERIORS
- STAINS & FINISHES, INTERIOR COATINGS
- TREES & SHRUBS, TRIM OFF BUILDING
- UV LIGHT BLACK LIGHT USES
- WALL SIDING TRIM & FINISHES
- FAQs below discusses field reports of problems & solutions for this topic
Frequently Asked Questions (FAQs)
Click to Show or Hide FAQs
No FAQs have been posted for this page. Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Ask a Question or Search InspectApedia
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Search the InspectApedia website
Technical Reviewers & References
Publisher's Google+ Page by Daniel Friedman
Click to Show or Hide Citations & References
- Shingle Shield™ are zinc strips that are inserted under the shingle tabs of individual shingles to reduce moss, lichens, and algae growth on asphalt roofing - see shingleshield.com
- StainhandleR are zinc strips that are inserted under the shingle tabs of individual shingles to reduce moss, lichens, and algae growth on asphalt roofing- see stainhandler.com
- Zinc-Shield® - zincshield.com and Z-stop™ zinc roofing strips - z-stop.com, are roll-out zinc strips intended for installation near the ridge of a roof to reduce moss, lichens, and algae growth on roofs
- 04/09: thanks to William M. Norman, P.E., S.E., Keeler-Webb Associates, 486 Gradle Drive, Carmel, IN 46032 for opening discussion regarding the legitimacy of extractive bleeding as a term to apply to asphalt roofing material. Mr. Norman suggests that many (not all) black stains on asphalt roofing may be due to algal growth. We will report progress in this discussion as updates to this web article.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
- The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.
- Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also Wiley.com. See our book review of this publication.
- Decks and Porches, the JLC Guide to, Best Practices for Outdoor Spaces, Steve Bliss (Editor), The Journal of Light Construction, Williston VT, 2010 ISBN 10: 1-928580-42-4, ISBN 13: 978-1-928580-42-3, available from Amazon.com
- The Journal of Light Construction has generously given reprint permission to InspectAPedia.com for this article. All rights and contents are ©Journal of Light Construction and may not be reproduced in any form.
- Architectural elements: the technological revolution: Galvanized iron roof plates and corrugated sheets; cast iron facades, columns, door and window caps, ... (American historical catalog collection), Diana S Waite, available used out of Amazon.
- Asphalt Roofing Residential Manual,
- Building Pathology, Deterioration, Diagnostics, and Intervention, Samuel Y. Harris, P.E., AIA, Esq., ISBN 0-471-33172-4, John Wiley & Sons, 2001 [General building science-DF] ISBN-10: 0471331724
- Building Pathology: Principles and Practice, David Watt, Wiley-Blackwell; 2 edition (March 7, 2008)
- Built-Up Roof Systems, Manual, C.W. Griffin, Mcgraw-Hill (Tx); 2nd edition (July 1982), ISBN-10: 0070247838, ISBN-13: 978-0070247833
- Concrete Folded Plate Roofs, C. Wilby PhD BSc CEng FICE FIStructE (Author), Butterworth-Heinemann, 1998, ISBN-10: 0340662662, ISBN-13: 978-0340662663
- Concrete Shell Roofs, C. Wilby PhD BSc CEng FICE FIStructE (Author),
- Concrete Dome Roofs (Longman Concrete Design and Construction Series),
- Concrete Roofing Tile, History of the, Batsford, 1959, AISN B000HLLOUC (availble used)
- Copper Roofing, by CDA
- Copper Roofing, Master specifications for copper roofing and sheet metal work in building construction: Institutional, commercial, industrial, I.E. Anderson, 1961 (hard to find)
- Corrugated Iron, Building on the Frontier, Simon Holloway
- Green Roof Plants: A Resource and Planting Guide, Edmund C. Snodgrass, Lucie L. Snodgrass, Timber Press, Incorporated, 2006, ISBN-10: 0881927872, ISBN-13: 978-0881927870. The text covers moisture needs, heat tolerance, hardiness, bloom color, foliage characteristics, and height of 350 species and cultivars.
- Green Roof Construction and Maintenance, Kelley Luckett, McGraw-Hill Professional, 2009, ISBN-10: 007160880X, ISBN-13: 978-0071608800, quoting: Key questions to ask at each stage of the green building process Tested tips and techniques for successful structural design
Construction methods for new and existing buildings
Information on insulation, drainage, detailing, irrigation, and plant selection
Details on optimal soil formulation
Illustrations featuring various stages of construction
Best practices for green roof maintenance
A survey of environmental benefits, including evapo-transpiration, storm-water management, habitat restoration, and improvement of air quality
Tips on the LEED design and certification process
Considerations for assessing return on investment
Color photographs of successfully installed green roofs
Useful checklists, tables, and charts
- Handbook of Building Crafts in Conservation, Jack Bower, Ed.,
Van Nostrand Reinhold Company, NY 1981 ISBN 0-442-2135-3 Library of
Congress Catalog Card Nr. 81-50643.
- Historic Preservation Technology: A Primer, Robert A. Young, Wiley (March 21, 2008)
- Historic Slate Roofs : With How-to Info and Specifications, Tina Skinner (Ed), Schiffer Publishing, 2008, ISBN-10: 0764330012
, ISBN-13: 978-0764330018
- Low Slope Roofing, Manual of, 4th Ed., C.W. Griffin, Richard Fricklas,
McGraw-Hill Professional; 4 edition, 2006, ISBN-10: 007145828X, ISBN-13: 978-0071458283
- Roof failure causes in depth (and specific methods for avoiding them)
- Roof design fundamentals and flourishes, based on voluminous industry research and experience
- New technologies and materials -- using them safely and correctly
- Comprehensive coverage of all major roofing systems
pecifications, inspection, and maintenance tools for roofing work
- Metal Roofing, an Illustrated Guide, R.A. Knowlton , [metal shingle roofs],
- Patio Roofs, how to build, Sunset Books
- Problems in Roofing Design, B. Harrison McCampbell, Butterworth Heineman, 1991 ISBN 0-7506-9162-X (available used)
- Roofing The Right Way, Steven Bolt, McGraw-Hill Professional; 3rd Ed (1996), ISBN-10: 0070066507, ISBN-13: 978-0070066502
- Slate Roofs, National Slate Association, 1926, reprinted 1977
by Vermont Structural Slate Co., Inc., Fair Haven, VT 05743, 802-265-4933/34. (We recommend this book if you can find it. It
has gone in and out of print on occasion.)
- Roof Tiling & Slating, a Practical Guide, Kevin Taylor, Crowood Press (2008), ISBN 978-1847970237,
If you have never fixed a roof tile or slate before but have wondered how to go about repairing or replacing them, then this is the book for you. Many of the technical books about roof tiling and slating are rather vague and conveniently ignore some of the trickier problems and how they can be resolved. In Roof Tiling and Slating, the author rejects this cautious approach. Kevin Taylor uses both his extensive knowledge of the trade and his ability to explain the subject in easily understandable terms, to demonstrate how to carry out the work safely to a high standard, using tried and tested methods.
This clay roof tile guide considers the various types of tiles, slates, and roofing materials on the market as well as their uses, how to estimate the required quantities, and where to buy them. It also discusses how to check and assess a roof and how to identify and rectify problems; describes how to efficiently "set out" roofs from small, simple jobs to larger and more complicated projects, thus making the work quicker, simpler, and neater; examines the correct and the incorrect ways of installing background materials such as underlay, battens, and valley liners; explains how to install interlocking tiles, plain tiles, and artificial and natural slates; covers both modern and traditional methods and skills, including cutting materials by hand without the assistance of power tools; and provides invaluable guidance on repairs and maintenance issues, and highlights common mistakes and how they can be avoided.
The author, Kevin Taylor, works for the National Federation of Roofing Contractors as a technical manager presenting technical advice and providing education and training for young roofers.
- The Slate Roof Bible, Joseph Jenkins, www.jenkinsslate.com,
143 Forest Lane, PO Box 607, Grove City, PA 16127 - 866-641-7141 (We recommend this book).
- Slate Roofing in Canada (Studi4es in archaeology, architecture, and history),
- Smart Guide: Roofing: Step-by-Step Projects, Creative Homeowner (Ed), 2004, ISBN-10: 1580111491, ISBN-13: 978-1580111492
- Solar heating, radiative cooling and thermal movement: Their effects on built-up roofing (United States. National Bureau of Standards. Technical note), William C Cullen, Superintendent of Documents, U.S. Govt. Print. Off (1963), ASIN: B0007FTV2Q
- Tile Roofs of Alfred: A Clay Tradition in Alfred NY
- "Weather-Resistive Barriers [copy on file as /interiors/Weather_Resistant_Barriers_DOE.pdf ] - ", how to select and install housewrap and other types of weather resistive barriers, U.S. DOE
- Wood Shingle Roofs, Care and Maintenance of wood shingle and shake roofs(EC), Stanley S. Niemiec (out of print)