Cement asbestos building siding shingles (C) Daniel FriedmanAsbestos in Building Siding Materials
How to identify & inspect asbestos-cement wall siding

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Asbestos-containing building siding identification & history:

This document provides a photo guide and text for the identification of asbestos-containing wall siding products like asphalt shingles & asbestos-cement siding shingles. We include a history of asbestos cement siding & roofing products.

This document assists building buyers, owners or inspectors who need to identify asbestos materials (or probable-asbestos) in buildings by simple visual inspection. In cement asbestos siding article series 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.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Photo Guide to Cement-asbestos Wall Shingles or Siding Products

Cement asbestos roof shinglesIn 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. This is the "wavy edge" asbestos cement shingle siding product.

But only the installer (me in this case) 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.

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.

[Click to enlarge any image]

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

Asbestos cement shingle siding, Hughsonville, NY (C) Daniel FriedmanAsbestos 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.

What forms of asbestos were used in fiber cement products?

Medium length asbestos fibres and possibly also asbestos shorts or fragments were used in fibre cement products.

The fibres, usually chrysotile asbestos (white asbestos), were used to impart strength or resistance to breakage of the asbestos cement product, while shorts or "dust" or fine asbestos particles were used in some products as a filler.

The types of asbestos used may vary, chrysotile is normally always present but crocidolite and amosite (asbestos grunerite) were also added to many products. - (Burdett 2007)

The building shown at left, located in Hughsonville, NY, using the "thatch edged" shingle siding style is almost certainly sided with asbestos-cement shingles.

From the 1940's to perhaps the early 1970's it was popular to cover peeling wood clapboard buildings with this durable material. We estimate that this building was probably re-sided in the 1960's.

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 reinforcing fiber used was asbestos.

Asbestos in granular or powder form may also have been mixed in with cement as a filler when these products were m anufactured.

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. At below left I point to an older asbestos cement siding shingle while to the right of my finger the next shingle is a modern asbestos-free fiber cement siding shingle.

I know the difference because I installed the new material. Otherwise, without close inspection or a lab test it would be difficult to say which was which.

New and old fiber cement and asbestos cement shingles side by side (C) Daniel Friedman New and old fiber cement and asbestos cement shingles side by side (C) Daniel Friedman

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.

Fiber cement siding shingle back side identification stamp (C) Daniel Friedman

Demolition debris from asbestos cement shingles (C) Daniel Friedman

Early History & Age of Asbestos-Cement Siding & Roof Shingles: Production & Use

Hatschek machine for cement asbestos  shingle or sheet production at  InspectApedia.com The Rosato text cited below and our research article and patent search on asbestos cement shingles and siding give insight into the history of and development of cement-asbestos shingles, siding, and cement board used on and in buildings.

Cementious siding and roofing such as fiber-cement siding, lap siding, and fiber cement roof shingles containing asbestos may then have appeared on homes constructed between 1906 and 1980 in North America and contining later in some other countries.

At CEMENT ASBESTOS PRODUCT MANUFACTURE we provide a more-detailed history of the development and use of asbestos in building and other products.

There we describe the Hatschek Machine for Production of Asbestos Sheet Goods.

It was not until 1907 that the invention by an Austrian engineer, Ludwid Hatschek, made possible the manufacture of pre -formed asbestos-cement products.

The Hatschek machine, a wet transfer roller, was used to produce the initial asbestos-cement sheets, while two other manufacturing processes included the Mazza process for pipes, and the Magnani semi-dry process for corrugated sheets. - Woods (2000)

We learn further from patent citations that asbestos-cement products were in use in the U.S. before 1910, as inventions often cite improvements to existing designs and that an explosion of patents and products making use of asbestos-cement ensued between 1907 and 1940.

The improved fire-resistance of cement asbestos roofing led to its recommendation in the U.S. by the National Board of Fire Underwriters in 1920. (National Board of Fire Underwriters 1920).

A similar-looking product, composite siding made of asphalt-impregnated fiberboard was also used for lap siding and wall shingles but is not an asbestos-cement product. See SIDING TYPES, INSTALLATION, DEFECTS for a guide to siding products of various types.

Research on Modern History of Uses ofr Asbestos

When was asbestos used in modern products?

Question: when was asbestos cement siding first used?

Carey Ceramo ceramic glazed asbestos siding from a 1950 catalog (C) InspectApedia.com2016/09/08 Gary said:

In what year did they start to use asbestos in cement siding ?

This question was posted originally at ASBESTOS DISPOSAL REGULATIONS


Gary, a reasonable guess for the start of widespread use of asbestos cement siding in the U.S. would be 1920, but patent disclosures and other research make clear that such products were in development and use one or two decades earlier.

The earliest use of asbestos in modern building products that I found was discussed in a Scientific American article published in 1876 and cited below. Asbestos researchers note that human interest in the properties and uses of asbestos is more than 2000 years old.

The following citations giving a history of the use of asbestos-cement in building products are arranged chronographically, rather than alphabetically - Ed.

Asbestos cement shinlgle patent in 1922 (C) InspectApedia.com

Planning demolition of cement asbestos siding or shingle siding materials?

Corrugated asbestos cement building siding in New York City (C) Daniel Friedman


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.

Our photograph at left illustrates that corrugated asbestos cement (or on newer buildings corrugated fiber cement) panels are also used as siding, not just as a roofing product.

This building was observed in New York City and based on its age, we suspect that the material shown is asbestos cement corrugated siding, not a newer fiber cement product.

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.


Continue reading at ASBESTOS CEMENT SHINGLE WEAR SIGNS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.




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