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Asbestos in Building Roofing Materials - How to identify asbestos-containing roofing MoldAPedia © Enter your search terms Submit search form   Search This Website - InspectAPedia.com

• How to recognize asbestos materials in building roofing materials, roof shingles, roof tiles
• During what years was asbestos included in roofing products like shingles or roofing felt paper?
• Photo guide to asbestos-containing roofing products, asphalt shingles, cement-asbestos shingles
• Photographs of asbestos containing roofing materials (ACRM)
• List of asbestos-containing building materials
• Non-asbestos materials sometimes mistaken for asbestos

Here is our photo guide and text that can help in identification of asbestos-containing roofing products like asphalt shingles & asbestos-cement roof shingles. This document assists building buyers, owners or inspectors who need to identify asbestos materials (or probable-asbestos) in buildings by simple visual inspection. In the website sections listed below, we provide photographs and descriptive text of asbestos insulation and other asbestos-containing products to permit identification of definite, probable, or possible asbestos materials in buildings.

While an expert lab test using polarized light microscopy may be needed to identify the specific type of asbestos fiber, or to identify the presence of asbestos in air or dust samples, many asbestos-containing building products not only are obvious and easy to recognize, but since there were not other look-alike products that were not asbestos, a visual identification of this material can be virtually a certainty in many cases.

Photo guide to asbestos containing roofing products

Most roofing materials are considered to be non-friable, and are probably less hazardous than other friable asbestos products such as asbestos pipe insulation. However removal of asbestos-containing roofing products is regulated as we discuss below.

Guide to Asphalt-asbestos Roof Shingles, Roll Roofing & Roofing Mastics & Coatings

(in process)

Also see our articles at ROOFING INSPECTION & REPAIR

Guide to Cement-asbestos roof shingles

Asbestos cement roof shingles were in popular use in the U.S. from the 1920's (est) through the 1960's (est). A mixture of asbestos fibers and portland cement the material was durable and fire resistant.

The typical life expectancy of an cement asbestos shingle roof was given as 30 years, but we've seen these roofs that were now 50 years old in good condition. Typical roof wear or failure patterns are either failure of the shingle fasteners or broken and falling shingles.

Asbestos cement corrugated roofing has been in use over the same time period and was generally a thicker material used in low-cost applications such as on sheds, barns, and low-income housing in some areas.

Roofing materials that use fibers and aggregate other than asbestos are properly called "fiber cement" roofing products. Some manufacturers use the term "fiber-reinforced cement" for these products. All of these products use some sort of fiber along with cement. Before 1978 in the U.S. the common fiber used was asbestos.

Cement asbestos shingles (or asbestos cement roofing shingles) have a medium in-place cost and durability compared with other roofing products and a a fire rating of Class A or B.

Also see Corrugated Cement-Asbestos Roofing.

Environmental Issues With Cement Asbestos Roof Shingles

The asbestos in cement asbestos roofing products is not friable under normal conditions. That is, it is not normally easily crushed into dust by hand. However very work asbestos cement shingles, or shingles that are mishandled during demolition (breaking into many small pieces, running power saws to cut the material) risks creating airborne asbestos-contaminated dust which could be a health and environmental hazard.

Also in some communities special measures and added costs are involved because of a requirement for air-testing during removal and possibly costs to dispose of the material in an appropriate landfill. (After all, originally this material came from the land.)

Some wear signs to watch for on cement asbestos roofs include these

• Active roof leaks - showing up in the attic or living area
• Broken cement asbestos roofing shingles (at the left of my hand in the photo above), possibly leaving exposed openings or nails - roof leaks (patch with sheet metal if necessary). Do not try walking on an asbestos cement shingle roof - you'll almost certainly break shingles at every step.
• Freeze-thaw damage: some modern reinforced fiber cement roof shingles are not intended for use in freezing climates and may lack resistance to frost damage. (That's why we don't like leaving moss on shingles.) If you are buying replacement fiber-cement shingles to repair an asbestos-shingle roof, check with the manufacturer about the suitability of the product for your location.
• Missing roofing shingles, probably leaving exposed roof sheathing and leaks Moss growing on the roof: we don't like seeing heavy moss or lichens or even leaves or pine needles on a building roof because these hold moisture which can speed the wearing out process, especially in freezing climates. Moss or lichens on a roof, especially the moss (lichens are hard to remove) can be reduced using industrial cleaners (like deck cleaner) if the contractor works carefully, or even by light brushing; usually we leave moss or lichens alone on an older roof as we are afraid of causing more damage than good.
• Mold and staining on roofs (mildew does not grow on roofs) is a mostly cosmetic concern that can be addressed by light gentle spray cleaning with a mildewcide or deck cleaner; be careful not to cause roof damage by too-aggressive use of a power washer. You can gradually kill off and prevent future moss or lichens or mold on most roof surfaces by installing aluminum or copper strips along the width of the roof near the ridge. Metal salts washing down the roof seem to kill off moss and lichens and most molds. You can convince yourself of the efficacy of this trick by simply noticing how often a roof surface is clean of moss and lichens below areas of metal flashing that are washed by rain.
• Prior repairs using tar, flashing cement - not a durable remedy, leaks likely
• Prior roof leaks showing up in the attic or living area, possibly repaired in a less than durable manner.
• Roof-over or re-cover limitations for fiber-cement roofs: NRCA says that some fiber-cement roofing products may not be suitable for a "roof-over" application; some roofing manufacturers permit roof-overs with their shingles, but the placement of any new roofing material on an old surface which is not smooth risks future shingle breakage, damage, and leaks. A "tear off" of the old roof is always a better roofing job (and it about doubles the cost).
• Slope limitations: beginning in about 1996 the NRCA recommended a minimum slope of 4 in 12 (33%) for these products; use on a low slope means shorter roof life or leaks.
• Underlayment requirements: in snow climates an underlayment is recommended to reduce the chances of ice dam leaks. See ... Prevent Ice Dam Leaks on Buildings

Maintenance Tips for Asbestos Cement Roof Shingles

We consider asbestos cement roof shingles a durable and fire-resistant roof and an asset to the building provided that the roof is in good condition. But because the material is easily damaged by a heavy-footed worker unfamiliar with the materials involved, asbestos cement roofs have to be repaired and maintained with the same care and expertise as slate roofs.This means that roof repairs may cost more even though the materials should also last longer than some competing roof systems.

Work by an inexperienced contractor can ruin a cement asbestos shingle roof and lead to complete roof failure. Small roof repairs to individual shingles can be made using copper or aluminum flashing material -- it will often weather to a color that looks alot like the remaining cement asbestos shingles, and this approach minimizes the chances of breaking more shingles during the repair. Follow our slate roof repair advice at SLATE ROOF INSPECTION & REPAIR.

Sources of Replacements for Asbestos Cement Roof Shingles

One manufacturer of cement-asbestos shingles was Ruberoid Co., who made 8" x 16" tapered singles with a surface pattern resembling wood and called "Ru-Ber-Oid-Eternit Tapered Timbertex Asbestos-Cement Shingles." 260 singles/525 lbs/square, were available in a wide range of colors.

Contemporary roofing product manufacturers make reinforced fiber-cement roofing shingles and other roofing products which look like, perform similarly to, and need to be installed similarly to the original asbestos-cement shingles - but these new products are free of asbestos. The replacements for asbestos cement roofing products are reinforced with a variety of fibers including fiberglass. Other replacements for asbestos-cement roofing use both different fibers and a different aggregate (perlite) to replace the asbestos. Some of the substitute products have been in use for more than 30 years (2008).

For maintenance or replacement of asbestos-cement roof shingles (or wall siding) contact Supradur Manufacturing Corporation, PO Box 908, Rye NY 10580 800-223-1948, or from within New York State, call 914-967-8230. Ask about their Supradur(R) mineral fiber shingles.

For handling and disposal guidance concerning old roofing material contact the US EPA, your state Department of Environmental Protection/Conservation, or your local building and health departments.

Also see our articles at ROOFING INSPECTION & REPAIR

Corrugated Cement-Asbestos Roofing

Virtually all of the inspection points, installation limitations, and environmental concerns which we discussed at Guide to Cement-asbestos roof shingles also apply to corrugated asbestos-cement roofing products.

Also see our articles at ROOFING INSPECTION & REPAIR

Asphalt-asbestos paints and sealants

Asbestos-filled asphalt paint was used damp proofing on building foundations and as a roofing sealant for many decades up to 1978

Also see our articles at ROOFING INSPECTION & REPAIR

OSHA Regulation of roof demolition where asbestos containing roofing materials ACRM are present

Beginning in 1986 OSHA set a permissible exposure limit (PEL) of 0.2 fibers per cubic centimeter (f/cc) of air over an 8-hour time-weighted average exposure period. OSHA also set an action level of 0.1 f/cc of asbestos for an 8-hour TWA average, and (the highest permitted short term asbestos fiber exposure) 1.0 f/cc "excursion limit" for a 30-minute time period. According to NRCA, the National Roofing Contractors' Association, their studies up to February 1992 had not found a single roofing job at which these limits were exceeded, and NRCA reported that in some cases no fiber release was detected.

We note that the association would have been referring only to asphalt-based roofing materials, not jobs involving the demolition of other ACRM such as cement-asbestos roof shingles (or "asbestos roof tiles" as some consumers refer to them) which might produce different statistics.

© Copyright 2008 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.

Technical Reviewers

Particular thanks are due to experts and also consumers who read these articles and suggest corrections, changes, and additions to the material. Content suggestions, technical corrections and content critique are invited for any of the content at our website.

• Daniel Friedman - principal author/editor of the InspectAPedia ^TM Website
• Asbestos products and their history and use in various building materials such as asphalt and vinyl flooring includes discussion which draws on Asbestos, Its Industrial Applications, D.V. Rosato, engineering consultant, Newton, MA, Reinhold Publishing, 1959 Library of Congress Catalog Card No.: 59-12535 (out of print).
• "Handling Asbestos-Containing roofing material - an update", Carl Good, NRCA Associate Executive Director, Professional Roofing, February 1992, p. 38-43
• EPA Guidance for Controlling Asbestos-Containing Materials in Buildings, NIAST, National Institute on Abatement Sciences & Technology, [republishing EPA public documents] 1985 ed., Exposure Evaluation Division, Office of Toxic Substances, Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency, Washington,D.C. 20460
• "Asbestos in the Home," U.S. EPA, Exposure Evaluation Division, Office of Toxic Substances, Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency, Washington,D.C. 20460
• NRCA Roofing and Waterproofing Manual, 4th Ed., available from the National Roofing Contractors' Association.
• "Tips for working with fiber-cement roofing products", Thomas L. Smith, AIA, RRC, Professional Roofing, September 1996
• Critique, contributions wanted: Contact Us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.

Use links just below or 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.

IDENTIFICATION of ASBESTOS in BUILDINGS
Asbestos Risk Assessment
Asbestos in Good Condition
Asbestos in Poor Condition
Asbestos Removal, Amateur, Incomplete
Asbestos Foamed-Over
Asbestos Air Ducts
Asbestos Air Duct Vibration Dampers
Asbestos Pipe Insulation
Asbestos Roofing Materials
Asbestos in unusual places
Carbon Nanotube Materials
Ceiling Tiles Containing Asbestos
Fireproofing containing Asbestos
Floor Tiles Containing Asbestos
Paper Duct Insulation Containing Asbestos
Transite Pipe Chimneys & Flues
Transite Pipe Air Ducts
Vermiculite Insulation Containing Asbestos
Other Asbestos-Containing Materials
Asbestos Under the Microscope
Asbestos-Free Insulation Materials
How to Identify Building Insulation Materials
Asbestos-Free Insulation Materials
Insulation Materials
  Asbestos Pipe Insulation
  Balsam Wool Batt Insulation
  Cotton Insulating Batts
  Cellulose loose fill insulation
  Fiberglass Insulation
  Foam Board Insulation
  Foam Spray Insulation
  Mineral Wool/Rock Wool Insulation
  Paper Duct Insulation
  Perlite Insulation
  Vermiculite Insulation

More expert information on Asbestos Identification, Recognition, & Testing

More Information on Asbestos Contamination, Other Airborne Fiber Hazards, & Building Diagnostic Inspections and Repairs

• Asbestos: How to find and recognize asbestos in Buildings - visual inspection methods, list of common asbestos-containing materials
• Asbestos HVAC Ducts and Flues field identification photos and guide
• Fiberglass: Indoor Air Quality Investigations: Health Concerns About Airborne Fiberglass: Fiberglass in Indoor Air from HVAC ducts, and Building Insulation
• Enviro-Scare: Electric Power Lines, Electromagnetic Fields, Cancer Risk, & "Enviro-Scare" - The Normal Curve Cycle of Public Fear of Environmental Issues
• Dust from the World Trade Center collapse following the 9/11/01 attack: the lower floors of this building contained spray-on fire-proofing asbestos materials.
• Asbestos Information Links: Asbestos Detection, Testing, Recognition, Hazards, Field Photos, and Information Sources, including health-related links such as legal services and information about mesothelioma and other cancers.
• Asbestos Identification and Testing References
• Asbestos Identification, Walter C.McCrone, McCrone Research Institute, Chicago, IL.1987 ISBN 0-904962-11-3. Dr. McCrone literally "wrote the book" on asbestos identification procedures which formed the basis for current work by asbestos identification laboratories.
• Stanton, .F., et al., National Bureau of Standards Special Publication 506: 143-151
• Pott, F., Staub-Reinhalf Luft 38, 486-490 (1978) cited by McCrone

For more information about fiberglass as an indoor air quality concern see:

• Fiberglass in Indoor Air, HVAC Ducts, and Building Insulation
• Fiberglass Particle Identification in the Fiberglass Test Laboratory
• Goodman Gray Flex Duct Deterioration and Failures
• Mold in Fiberglass Insulation
• Optimum Indoor Air Filters
• Owens Corning Flex Duct Deterioration and Failures
• World Trade Center Dust Particle Identification

For more information about asbestos as an indoor air quality concern with focus on easy ways to identify asbestos materials in buildings, see:

• Asbestos Identification in Buildings: How to find & identify asbestos-containing materials
• Asbestos in Good Condition
• Asbestos HVAC Ducts - Asbestos Materials On or In Heating and Cooling Duct Work
• Asbestos paper duct wrap
• Asbestos Transite Chimneys, Flues, & Pipes in Buildings
• Asbestos under the microscope
• Asbestos Vibration Dampers & Asbestos in the Air Handler
• Ceiling tiles: How to recognize ceiling tiles that may contain asbestos
• Examples of unusual uses of asbestos in buildings

Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Research & Advice

The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems

Home Inspection Construction Consulting Services & advice for home buyers

Use this simple, economical mold test kit by following our instructions on how to collect and mail mold samples to our lab

Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.

Contact Daniel Friedman for website content suggestions or for fee-paid consulting

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