Asbestos Dust Hazards from Cement Asbestos Roofing or Siding Shingles

How to evaluate the level of hazardous asbestos dust exposure
Explanation of asbestos dust hazards

POST a QUESTION or COMMENT about dust hazards from removal or demolition of cement asbestos roofing or siding

Dust hazards from asbestos cement siding or roofing demolition or removal: this article discusses potential asbestos-dust hazards from power-sawing cement-asbestos siding materials.

This article series 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.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

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Asbestos Dust Hazards from Cement-asbestos Wall Shingles or Roofing Products

Is it safe to buy a home with cement asbestos siding? Most cementious building 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 at ACRM Roofing Disposal Regs.

Asbestos-cement products were developed in an era of ingenuity for creating easy to install and economic building materials.

Although asbestos-cement has acquired a poor reputation by association of its title, it has not gained that reputation through a lack of durability or utility. In order to preserve this twentieth-century material, understanding what makes, or does not make, asbestos a hazard is truly important.

In this case, no hazard is created when asbestos-cement building materials are sound and left in place, or when treatments incorporate non-abrasive means. - "Keeping a Lid on It...|, Woods, NPS technical brief

Should We Worry about Sawing Asbestos Cement Shingles?

Reader question: I was helping an older gentleman fix a screen door that was brushing the siding of the over hang of his house.

I just got a saw and trimmed a quarter inch off of a 4 foot section ....later it came to my mind that it was likely cement asbestos type siding...loks just like the picture you have that is pointing to the siding.

The cutting was overhead and dust and debris was flying. I did not wear a mask ...I didn't realize it was that type siding.

Should I be concerned? Or is it long term exposure that would typically be more of an issue?

I would appreciate any feedback you can give me. - M.S.

Reply: Maybe ..

For an accurate answer to your question of whether or not you exposed yourself (and anyone else nearby) you'd need to:

Confirm that the material you were sawing contained asbestos -

though in fact breathing high levels of nearly any construction demolition dust can be a respiratory irritant or worse. 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.

See ASBESTOS CEMENT SIDING or for a more broad look at identifying asbestos-containing materials

See ASBESTOS IDENTIFICATION IN BUILDINGS.
Estimate of the amount of asbestos-containing dust to which you were exposed,

its concentration in the air, how long you were breathing it. In our opinion it's not so likely that making a single 4-foot power cut along asbestos-containing material produced a large asbestos contamination issue, but it is more of a concern that using a power saw to cut any asbestos-containing product produces a cloud of fine dust particles that was right in the face of the person operating the equipment.
Consult with a doctor

who specializes in environmental medicine.
Clean up asbestos-containing dust and debris

from the job. A acceptable approach to cleaning up any asbestos dust mess that you may have left at the jobsite

So really we don't know the answer. Very acute exposure to high levels of asbestos containing dust, such as workers at the world trade center collapse on 9/11/01, indeed has led to health problems for those individuals, as has been much in the news.

A different example of hazardous dust exposure that was serious was that of workers in industry or shipyards who were exposed to high levels of dust (less than the WTC collapse) over long periods of time.

A short exposure to low dust levels may not produce a measurable effect on someone. For example, asbestosis among contractors who installed asbestos-insulated heating piping has not been widely reported, while asbestosis among shipyard workers, workers in brake shoe factories, and emergency workers at the 9/11 site has been a concern.

We can suggest several steps:

Consult with an environmental physician, describe your exposure, and ask what symptoms, complaints, or tests you should watch out for or consider
Watch out: there are many many lawyers, a few doctors, and others who profiteer on environmental-fear and who may be happy to offer you costly services that you don't need - that's why you should start with a professional MD who has experience in this field
DO NOT do that again - it's a bad idea to run power saws, grinders, etc. that make dust out of asbestos containing siding.

Background On Asbestos Dust Hazards

As we discuss at ASBESTOS CEMENT SIDING:

Asbestos cement wall 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.

Siding materials that use fibers and aggregate other than asbestos are properly called "fiber cement" building siding 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.

In this photo of a house in New York State we can see both original cement-asbestos wall shingles and newer fiber cement replacement wall shingles that do not contain asbestos. But only an expert or a lab can tell the new fiber cement from the old asbestos fiber cement shingles - or you can with help of the inspection and repair tips we provide below.

How can we tell the difference between asbestos-containing shingles and fiber-cement wall shingles?

It's tricky.

But here are some ways to distinguish between asbestos containing shingles and non-asbestos fiber-cement shingles:

Age or date of installation

: installed before 1978 the shingles probably contain asbestos.

Layers of paint or finish coatings;

the original shingles of both asbestos-cement and fiber cement usually come from the factory painted white on one side.

Owners often painted cement asbestos shingle siding to make it look fresh, or if it was weathered and fuzzy, to preserve it.

On a building that has has a portion of its original cement asbestos shingles replaced with newer fiber cement shingles, and where some original asbestos cement shingles remain, you'll see a difference in the thickness of layers of paint on the two materials.

The shingle at the right in this photo clearly has fewer paint layers than the one at left. The left shingle is an older asbestos-cement shingle and the right photo is a new fiber cement shingle we installed.

If an asbestos-cement sided home has been re-modeled such as by adding a window or door, it's likely that the old asbestos cement shingles were broken around that new opening during the construction work - expect to see newer fiber cement shingles there.

The back of a new fiber cement wall shingle

will probably have a code stamped on it such as we show here.

The presence of old dirty demotion materials

may suggest that old asbestos cement shingles have been removed from the home even when new, completely different materials are installed.

We found this cement asbestos siding debris on the ground around a home that boasted new vinyl siding.
The presence of multiple layers of exterior siding

can be spotted by noticing that the wall cladding extends out past the original window or door trim. But beware; when we renovated the building shown above we built-out the exterior trim so that it would continue to project beyond new vinyl siding installed on some wall surfaces.
The nails

used to secure the shingles probably won't help unless some are obviously different from others; installers use the same galvanized box nails to hang these shingles as they did in 1955.

Asbestos dust hazards created during demolition / removal of cement asbestos siding or shingle materials

The risk of high levels of airborne asbestos from cementious products is probably very low unless the workers are using power equipment like sanders and saws on these substances.

Using cement asbestos roofing products as an example, 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.

But it appears that the association may 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.

See ASBESTOS MATERIAL REGULATIONS

and ASBESTOS REGULATION Update that address the handling of asbestos containing building materials, including ACM (asbestos containing materials), PACM (presumed asbestos containing materials), SACM (suspect asbestos containing materials), and ACRM (asbestos containing roofing materials).

Also see other cementious siding materials such

as JAMES HARDIEPLANK® FC SIDING (also see Hardie's Fibrolite™ or Fibro where used in Australia) and cementious roofing materials such

as ASBESTOS & FIBER CEMENT ROOFING

and Corrugated Cement-Asbestos Roofing.

Also see Environmental Issues - Asbestos Roofing/Siding.

A common remodeling practice is to install new vinyl or aluminum siding over cement asbestos shingle siding as well as over many other older siding materials when the old siding has become damaged, leaky, or cosmetically ugly. A typical procedure is to install furring strips on the existing wall, avoiding breaking the existing siding. The new siding is then secured to the furring strips so that the new wall siding will be smooth and flat. Please

see ASBESTOS CEMENT SIDING-OVER for the full article on this topic.

Additional steps may be needed to build out window and door trim for aesthetic reasons - so that the windows and doors do not appear to "recede" into the walls of the structure.

What about replacing the cement asbestos siding or roofing ?

Can you side over the existing asbestos cement siding or roof over cement asbestos roofing or does it need to be removed?

It is very difficult to remove individual broken asbestos-cement wall or roof shingles, but working carefully it can be done. Work by an inexperienced contractor can ruin a cement asbestos shingle wall siding and lead to complete replacement that could have been avoidable.

...

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Citations & References

In addition to any citations in the article above, a full list is available on request.

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
EPA, ASBESTOS IN YOUR HOME [PDF] - 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
"Copy on file as - /exterior/Asbestos_Cement_Shingles_NPS.pdf - Keeping a Lid on it - Asbestos Cement Building Materials - ", Amy Lamb Woods, Technical Preservation Services, National Park Service, 2000. Web search 07/08/2010 original source: http://www.nps.gov/history/hps/tps/recent past/asbestosarticle.htm
Asbestos-cement products were developed in an era of ingenuity for creating easy to install and economic building materials. Although asbestos-cement has acquired a poor reputation by association of its title, it has not gained that reputation through a lack of durability or utility. In order to preserve this twentieth-century material, understanding what makes, or does not make, asbestos a hazard is truly important. In this case, no hazard is created when asbestos-cement building materials are sound and left in place, or when treatments incorporate non-abrasive means.
- END NOTES to the above article provide excellent historical references for asbestos cement products:
  1D.V. Rosato, Asbestos: Its Industrial Applications (New York: Reinhold Publishing Corp., 1959), 1, 62. This text is an excellent resource for information on the manufacture and production of asbestos products.
  2 L. Michaels and S.S. Chissick, eds., Asbestos, Properties, Applications, and Hazards (New York: Wiley, 1979), 1-2. Resource for various kinds of asbestos, their properties and chemical constituencies.
  3 Arnon Bentur and Sidney Mindess, Fibre Reinforced Cementitious Composites (London: Elsevier Applied Science, 1990), 288-304. This text reviewed long-term performances of asbestos-cement and concluded that “in natural weathering the composite is excellent.” More detailed quantitative material properties are also given in this text.
  4 L. Michaels and S.S. Chissick, eds., 306-312
  5 United States Department of the Interior Bureau of Mines, Materials Survey: Asbestos, (Washington D.C.: US Government Printing Office 1952), I-1 - I-4.
  6 Caleb Hornbostel, Construction Materials: Types, Uses and Applications (New York: John Wiley & Sons, 1978), 82.
  7 H. W. Johns, Patent Trademark Materials: Asbestos (New York: H. W. Johns Manufacturing Co., 1878), 12.
  8Rosato,63.
  9 D.A. St John, A.B. Poole, and I. Sims, Concrete Petrography: A Handbook of Investigative Techniques (London: Arnold Publishers, 1998), 320-322.
  10"Asbestos-Cement Products for War buildings," Asbestos (April 1942), 2-4
  11 Rosato, 75.
  12 The National Board of Fire Underwriters, Dwelling Houses (New York: The National Board of Fire Underwriters, 1920), 36-37.
  13 Ernest G. Blake, Roof Coverings: Their Manufacture and Application (New York: D. Van Nostrand Company, 1925), 144-171. Resource for detailed descriptions of many asbestos-cement roof shingle forms, styles, and hardware.
  14 James McCawley, Asphalt and Asbestos-Cement Shingle Residing (New York: United Roofing Contractors Association, 1940).
  15 E. Lechner, “Recent Innovations in the Manufacture of Asbestos-cement,” Cement and Cement Manufacture, 7:6 (June 1934), 180-181.
  16 R.C. Smith, Materials of Construction, Third Edition (New York: McGraw-Hill Book Company, 1979), 358-359
  17 Asbestos Shingle, Slate and Sheathing Company, Asbestos Corrugated Sheathing (Ambler, Pennsylvania: The Keasbey & Mattison Company, 1913), 1.
  18 “Johns-Manville” product advertisement, Sweet’s Catalogue of Building Construction (F. W. Dodge Corporation, 1906-1961), 8b/4.
  19 Rosato, 63.
  20 National Trust for Historic Preservation, "Coping with Contamination: A Primer for Preservationists," Information Bulletin No. 70 (1993), 12.
  21 Bentur and Mindness, 304.
  22 Guidance given here only makes recommendations based on national agency laws and regulations; all applicable federal, state, and local laws and regulations must be followed for any asbestos-containing material project.
  23 Roger C. Whitman, More First Aid for the Ailing House (New York: McGraw-Hill Book Company, 1977), 282.
  24 Martin E. Weaver, Conserving buildings, Guide to Techniques and Materials (New York: John Wiley & Sons, Inc., 1993), 26.
  25 D.J. Hannant, Fibre Cements and Fibre Concretes (New York: John Wiley & Sons, 1978), 146-155. This reference give quantitative engineering properties for asbestos-cement and other fiber-cements..
  26 "The Industrial Uses of Asbestos," Scientific American (22 April 1876), 258-259.
  27 John E. Wilden, A Guide to the Art of Asbestos Cement (Winchester, England: Taylor & Partners Translations, 1986), 108. This resource is primarily concerned with the experience or art of producing asbestos-cement and reflects the practical side of production.
Malco® TSFC Tubo Shear fiber cement cutting tool (sold at Amazon and at other tool distributors) and also the Malco TSF2A Shear Cutting Tool, a heavy-duty pneumatic shear cutting tool for the same purpose (available at Amazon.com) Malco Products, http://www.malcoproducts.com/ specializes in producing tools for the HVAC trade. Malco Products, Inc. - PO Box 400, 14080 State Highway 55 NW, Annandale, MN 55302-0400 P: 800-328-3530 Fax: 320-274-2269
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

ASBESTOS IN YOUR 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
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, ROSATO 1959, D.V. Rosato, engineering consultant, Newton, MA, Reinhold Publishing, 1959 Library of Congress Catalog Card No.: 59-12535 (out of print, text and images available at InspectAPedia.com).
EPA ASBESTOS MATERIALS BAN: CLARIFICATION 1999
"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
In addition to citations & references found in this article, see the research citations given at the end of the related articles found at our suggested

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Asbestos Dust Hazards from Cement Asbestos Roofing or Siding Shingles

How to evaluate the level of hazardous asbestos dust exposure
Explanation of asbestos dust hazards

Asbestos Dust Hazards from Cement-asbestos Wall Shingles or Roofing Products