Asbestos cement sheet product production, properties, & uses: this article describes asbestos cement sheet materials including asbestos roofing tiles or shingles, asbestos-cement shingle siding, flat asbestos-cement sheet products such as asbestos millboard and asbestos insulation, and corrugated asbestos sheeting used for both roofing and siding.

Cement asbestos materials: this article series describes asbestos cement products & materials and the history of their production and use.

This article includes text & data Adapted from Rosato (1959 out of print) on the production and use of asbestos-containing materials, adding photographs, inspection, repair and maintenance advice, and updates on asbestos hazards involved in the installation, repair, or demolition of asbestos cement products such as roofing and siding or asbestos millboard that remain in place on buildings.

Our page top photograph shows badly broken cement asbestos roofing shingles on a building in upstate New York.

Asbestos Cement Sheet Products

The following text is adapted & expanded from Rosato p. 75-78 [1] © 2021 InspectApedia.com

Asbestos is safe and legal to remain in homes or public buildings as long as the asbestos materials are in good condition and the asbestos can not be released into the air. - US EPA

[Click to enlarge any image]

The major production of asbestos-cement materials is in the form of shingles and sheets. The principal products, in order of their volume,* are siding shingles, flat sheets, roofing shingles, and corrugated sheets. Flat sheets and corrugated sheets are utilized for interiors as well as exteriors.

The oldest use of asbestos-cement products involves the use of fire-proof roofing shingles.

Additional products manufactured are simulated ceramic bathroom tile, facings of acoustical materials, electrical switchboard panels, laboratory table tops, electrical conduits, electrical sheets, and others.

Asbestos-cement sheets are made either in the dry or wet mixing process.

Manufacture of Asbestos Cement Siding Shingles.

Asbestos-cement siding is being used in millions of homes, inasmuch as it is both attractive and 'serviceable. Sidings are presently available with improved weather-resistance and with distinctive surface texture or color. They have been accepted widely for exterior use in new homes of all price groups.

* The Asbestos-Cement Products Guide, New York, Asbestos-Cement Products Association.

** "Advanced Designing with Asbestos Siding," New York Asbestos-Cement Products Assoc.

The colors are permanently embedded throughout the sheet. They will not powder or peel off. Different methods to improve the weather resistance of siding have been developed.

They are used in the dry process. Sodium silicates are one of the materials used for this purpose. Originally, they were not successful since they were only insoluble after baking at temperatures higher than 900°F.

This temperature condition is detrimental to the cement base. A combination of sodium silicate and sodium fluoborate becomes stable when heated at 500°F for 1/9 hr. After the reaction has occurred, an insoluble semi-gloss finish is produced. To pro-duce approximately one ton of material, 48 lb of sodium silicate and 6 lb of sodium fluoborate can be used with 16 lb of water and 18 lb of iron oxide pigment.

Silicone resins have been developed for use with asbestos-cement shingles to provide for a water repellent structure. One example involves coating a silicone composition on shingles to make them water repellent and bloom resistant.

Asbestos Cement Siding:

some building siding materials contain asbestos: Cement-asbestos siding shingles (photo at left) (non-asbestos-containing replacement products now available) and cement asbestos board siding as well as undersheeting.

This is a cementious material and is unlikely to release significant levels of airborne asbestos fibers unless during severe demolition activities or someone using a power saw or sander on the material.

See ASBESTOS CEMENT SIDING for more details about cement asbestos building siding, its repair, removal, demolition, or cover-over.

Manufacture of Asbestos Cement Roofing Shingles

Asbestos-cement roofing shingles provide for permanent and decorative structures.

The weather resistant and fire resistant characteristics of shingles make them desirable for both industrial and home applications.

They provide for one of the light, weight-high strength roof-ing materials.

They are available in colors which range from light pastels to deep tones and include both white and black.

Some shingles are designed in solid colors, while others pro-vide a blended color effect..

Painting is not needed to pre-serve shingles but if a change in color is desired, they can be painted.

See details at FIBER CEMENT SIDING PAINTS

 

Properties & Manufacture of Asbestos Cement Flat Sheets & Asbestos Millboard

Asbestos-cement flat sheets were at one time manufactured only in the typical gray color of cement and usually only accepted for industrial purposes. However, they are now available in such a variety of colors and surface finishes that their usefulness has been greatly expanded.

Chrysotile asbestos is the principal source for these products.

* Philadelphia Quartz Co.. 32, No. 6, P and Q, Philadelphia, Penna.
Union Carbide Corp., American Patent 2, 833. 673 (May 6. 1958).

Sheets are available with smooth surfaces; they are waxed or lacquered with a variety of colors for use as office partition walls, kitchen walls, table tops, acoustical panels, electrical sheets, building corridors; they are used generally where ease of cleaning is important.

Flat sheets are used both internally and externally. Exterior sheets are made so that they resist outdoor weather. They are impervious to water; they prevent the entrapment of moisture within the building walls, a situation which would normally cause the decay of wood. Decorative sheets can be used for table tops to provide chemical resist-ant surfaces.

Complete asbestos-cement boards or flat sheets are used; however, combinations incorporate asbestos-cement in sandwich structures. "Transitop" * is a typical composition board consisting of an integrally impregnated insulating board core, faced on both sides with asbestos-cement board. Waterproof adhesive is used to laminate the insulating core as well as to bond the noncombustible asbestos-cement faces to the core.

This combination of materials provides for structural strength, high insulation values and maintenance-free interior and exterior finish in a single fire-resistant panel. See Table 3.2. It is suitable for indoor or outdoor use. The wood fiber insulating core is integrally impregnated to provide maximum strength and a highly resistant barrier to moisture without appreciably affecting the insulating properties.

The conductivity of the core complies with Federal Specification LL.L-F-321h-Class A. The sheet products are also used where electrical requirements exist. Examples of electrical applications are provided by Canadian Specifications; Spec. 34-GP-8 pertains to asbestos-cement electrical conduit.

Asbestos Cement board used as a "fire proofing" over and near boilers and wood stoves - also called "cement wallboard" and "asbestos millboard".

Note that asbestos cement board is a hard cementious product easily distinguished by eye from more friable and dangerous soft asbestos panels used as building fireproofing such as these almost pure tremolite asbestos ceiling panels shown above.

More about this building can be read

at ASBESTOS FIREPROOFING SPRAY-On Coatings.

Asbestos millboard (photo at above left) used for stoves and heaters, in garages, as fireproof wallboard, as gaskets, as washers in electrical applications, stove mats, safes, motion picture booths, automobile hoods. Asbestos millboard is a cementious product that was produced in sheets and used for fire barriers and in other applications.

The material is quite similar to cement asbestos roof shingles and siding, and was produced in sheets of varying thickness (typically 1/8"- 1/4") and dimension depending on its intended use.

Asbestos millboard was used as a fire barrier behind and over and around wood stoves, coal stoves, & heating appliances in buildings up to 1978. It was also used in some locations where a moisture-resistant building material was desire.

Also see ASBESTOS CEMENT FLAT SHEETS

* Johns-Manville Corp.

Rosato detailed the production of asbestos millboard. He described asbestos millboard as a "heat insulation" product, an appellation with which we disagree.

Because of its dense and cementious nature asbestos millboard, while fireproof, can conduct heat towards combustible materials that it might cover, such as wood framing. Without an adequate air space or other insulation, heat conducted through non-combustible materials can still result in a fire. (Rosato 1959, 100-102)

Because the production methods used for asbestos millboard are essentially the same as for asbestos paper, also see details

at ASBESTOS PAPER DUCT INSULATION - manufacturing process description.

Details about how asbestos cement board or millboard was produced are

at ASBESTOS MILLBOARD PRODUCTION

Perforated asbestos-cement

Perforated cement-asbestos sheets are manufactured with sound absorbing elements. These particular sheets are used in broadcasting studios, music rooms, and auditoriums where specific resistance to fire and moisture exists. Federal Specifications SS-A-118b, Type 2a and Class A are applicable.

Notes to the table above

* Johns-Manville corp.

Manufacture of Asbestos Cement Corrugated Sheets.

Asbestos-cement corrugated sheets are generally only produced in the color gray.

Their principal use has been for industrial walls and roofs where corrosion resistance is important. In recent years, this type product has been incorporated in farm buildings, commercial interiors and home exteriors. Its principal use on the farm is based on fire safety, strength and resistance to rats and termites.

Our photo, left, shows typical corrugated asbestos cement roofing installed. T

he dark areas are probably algae and the light reddish-brown areas may be a form of lichens.

Details and more photos of corrugated cement asbestos products are found

at CORRUGATED CEMENT ASBESTOS ROOFING.

Asbestos Insulating Board Cleaning or Repair

• HSE, UK, CLEANING LIGHT FITTINGS ATTACHED TO ASBESTOS INSULATING BOARD (AlB) [PDF] (2017) UK Health and Safety Executive, retrieved 2021/11/11 original source: https://www.hse.gov.uk/pubns/guidance/a5.pdf
  
  Excerpts: This sheet describes good practice when you need to clean a contaminated light fitting attached to AlB, eg to change a bulb or tube. This sheet is not appropriate where the AlB is damaged or may be damaged, eg by ‘rocking’ the screws during cleaning. Use an HSE licensed contractor for such work. See sheet em4 Using a Class H vacuum cleaner for asbestos when removing a screwed-in fitting, and sheet a6 for minor damage repair.
  
  This guidance is issued by the Health and Safety Executive. Following the guidance is not compulsory, unless specifically stated, and you are free to take other action. But if you do follow the guidance you will normally be doing enough to comply with the law. Health and safety inspectors seek to secure compliance with the law and may refer to this guidance.
• HSE, UK, ENCLOSING UNDAMAGED ASBESTOS MATERIALS to PREVENT IMPACT DAMAGE [PDF] (2007) UK Health and Safety Executive, retrieved 2021/11/11 original source: https://www.hse.gov.uk/pubns/guidance/a8.pdf
  Excerpt:
  This sheet describes good practice when you need to protect asbestos materials from impact damage, and you do not want to remove them. Examples include:
  
  asbestos insulating board wall panels that could be damaged by trolleys; or
  
  lagged pipework running along the bottom of a wall that could be scuffed.
  ...
  This sheet is NOT appropriate where the asbestos material is badly damaged or where you disturb the asbestos. Use an HSE-licensed contractor for such work.
• HSE, UK, REPAIRING MINOR DAMAGE to ASBESTOS INSULATING BOARD (AIB) [PDF] UK Health and Safety Executive, retrieved 2021/11/11 original source: https://www.hse.gov.uk/pubns/guidance/a6.pdf
  
  Excerpt: This sheet describes good practice when you need to repair small areas of damaged AlB, eg a broken corner or scratches. This sheet is not appropriate: if work lasts more than one hour for one worker in a seven-day period, or exceeds two hours for two or more workers in a seven-day period; where the material is badly damaged. Use an HSE-licensed contractor for such work.
• HSE, UK, USING a CLASS H VACUUM CLEANER for ASBESTOS [PDF] (2017) UK Health and Safety Executive, retrieved 2021/11/11 original source: https://www.hse.gov.uk/pubns/guidance/em4.pdf
  
  Excerpt: This sheet describes the Class H vacuum cleaner, how to use it to minimise asbestos fibres released during a task, and how to use it to clean contaminated items. The cleaner must comply with British Standards. A Class H vacuum is not mandatory for non-licensed work but can be a useful piece of equipment on a number of tasks. Never use domestic vacuum cleaners, even those fitted with high efficiency particle arrestor (HEPA) filters as these are not adequate for use with asbestos, and will allow asbestos fibres to pass straight through.

...

---

---

ADVERTISEMENT

---

---

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2022-06-11 by InspectApedia-911 (mod) - condition of asbestos cement panels will determine proper steps to take

@Terry,

No.

But you might want to inspect its condition to see if there are repairs needed. If there's severe weathering you might want to paint it. Don't power wash it.

You'll see more details about safety, care of, & repairs to asbestos cement siding and it's younger brother, fiber cement siding, in the index to related articles.

On 2022-06-11 by Terry

We have discovered that our building built in 1976 uses Asbestos cement panels for the exterior of the building. Does this material need to be removed?

On 2022-02-18 by Inspectapedia Com Moderator

@Al,

Possibly in some special construction applications but certainly not likely in a common building or residential structure design.

On 2022-02-18 by Al

Would there be asbestos in a concrete foundation circa 1979/1980?

On 2021-12-26 by ruth woods

@Inspectapedia Com Moderator, im not talking about leftover dust from it but the dangers if it does contain asbestos in the cement mix and further exposure down the years,would asbestos not become airborne of it just laying there or would it have to be busted up again to be a danger?

On 2021-12-25 by Inspectapedia Com Moderator - need factual information to determine presence of asbestos

@ruth woods,

A fictional but nevertheless expert and smart medical forensic detective (Thorndyke) remarks in Richard Austin Freeman's (1862-1943) "The Vanishing Man ..."

... there is no use in speculating a priori; we should have to reconstruct a purely imaginary situation, the circumstances of which are unknown to us, and we should almost certainly reconstruct it wrong.

That's what our discussion here is being pressed to do.

We don't know if there was asbestos, we don't know the possible outdoor airborne levels nor the variation in such a level from dust from the debris, and we have no basis for guessing beyond my original reply: uncommon but possible.

Without that factual information, further speculation and worry about the possibilities of leftover dust of an uncertain material of uncertain hazard at an unknown level are, with all due respect, simply so speculative and lacking in data as to not be useful.

If the presence of the material is causing you worry, that worry by itself can be a health hazard that might make collecting samples and having them tested by a certified environmental or forensic lab could be justified.

On 2021-12-25 by ruth woods

@inspectapedia.com.moderator, ok so since the concrete pieces have already been broken into smaller pieces from the driveways and such and they are put on the bank,if they were asbestos containing would it get into the air since the sides are broken up?

On 2021-10-21 by inspectapedia.com.moderator

@ruth woods,

As you referred to in your first comment, it looks like a section of a walkway, patio, driveway or other surface using concrete and bricks.

On 2021-10-21 by ruth woods

@inspectapedia.com.moderator, im wondering if you know what this would be or was used for thats in the back hoe?

On 2021-10-15 by inspectapedia.com.moderator - asbestos unlikely in broken up concrete debris

@ruth woods,

It's possible that it contains asbestos, probably not however.

Is it hazardous? Not particularly when you have basically non-friable cementious material without chopping, grinding, or sawing it up to make a lot of dust.

On 2021-10-15 by ruth woods

@inspectapedia.com.moderator, ok my neighbor has put this all over the creek bank and my cats wonder all on it so wondering if there would be a danger of it getting on my cats if it has asbestos

would asbestos be in old concrete driveways,foundations,sidewalks and such

...

On 2021-01-05 by danjoefriedman (mod) - what percentage of asbestos within a corrugated roof sheet

Anon:

Keep in mind that corrugated fiber cement sheets made after your country stopped using asbestos will contain no asbestos at all;

Among asbestos-cement products, the asbestos content reported by asbestos test labs varies considerably depending on just what process is used and what the lab checks-for (e.g. long fibres vs. short asbestos "dust" used as filler in many products); as a result you might see lab reports stating asbestos content as "above 2%" to as much as 30% or even more in some products.

Typically, however, American made asbestos cement shingles and roofing contained about 18% asbestos, while imported products contained around 13% asbestos - note that this is by weight, not by volume. (Asbestos is light.)

Other sources (Woods 2000) claim that

The proportion of cement to asbestos fibers varied over a range of ten to seventy-five percent by weight, depending on the desired characteristic.

See details in

ASBESTOS CEMENT SHINGLES PRODUCT DESCRIPTION [PDF]

Additional References:

Woods, Amy Lamb, "KEEPING A LID ON IT: ASBESTOS-CEMENT BUILDING MATERIALS" [PDF]

Who was in turn citing

D.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.

- a book that we have re-published here at InspectApedia.com at

ASBESTOS, ITS INDUSTRIAL APPLICATIONS, Rosato 1959

On 2021-01-05 by Anonymous

what percentage of asbestos within a corrugated roof sheet

 

...

Continue reading  at CEMENT ASBESTOS PIPE MANUFACTURE or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• Asbestos, Its Industrial Applications - Rosato: Text & Chapter Index [1]
  • ASBESTOS, ITS INDUSTRIAL APPLICATIONS, ROSATO 1959
  • ASBESTOS ORIGIN & NATURE - p. 1-36
  • ASBESTOS PROPERTIES - p. 37-61
  • ASBESTOS CEMENT PRODUCTS - p. 62-66
  • CEMENT ASBESTOS PRODUCT MANUFACTURE - p. 66-73
  • CEMENT ASBESTOS PRODUCT CURING - p. 73-75
  • CEMENT ASBESTOS SHEET PRODUCTS - p. 75-78
  • CEMENT ASBESTOS PIPE MANUFACTURE - 78-85
  • ASBESTOS TILE MANUFACTURE - p. 86-93
  • ASBESTOS INSULATION - 94-105
  • ASBESTOS ELECTRICAL WIRE INSULATION - p. 106-112
  • ASBESTOS FRICTION MATERIALS - p. 113-129
  • ASBESTOS TEXTILES - p. 130-141
  • ASBESTOS in PLASTICS - p. 142-177
  • ASBESTOS PACKINGS & GASKETS - p. 178-184
  • ASBESTOS FILTERS - p. 185-193
  • ASBESTOS OTHER PRODUCTS - p. 194-200
  • ASBESTOS BIBLIOGRAPHY - p. 201-207
• ASBESTOS & FIBER CEMENT ROOFING - home
• ASBESTOS MILLBOARD
• SIDING, FIBER CEMENT
• FIBER CEMENT PRODUCT MANUFACTURERS
• FIBER CEMENT PRODUCT STANDARDS
• FIBER CEMENT ROOF SHINGLE ASBESTOS TEST RESULTS

Suggested citation for this web page

CEMENT ASBESTOS SHEET PRODUCTS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to ASBESTOS HAZARDS

Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia

Ask a Question or Search InspectApedia

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.

Note: appearance of your Comment below may be delayed: if your comment contains an image, photograph, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Apologies for the delay.

Only one image can be added per comment but you can post as many comments, and therefore images, as you like.
You will not receive a notification when a response to your question has been posted.
Please bookmark this page to make it easy for you to check back for our response.
Our Comment Box is provided by Countable Web Productions countable.ca

Citations & References

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

---

ADVERTISEMENT

---