InspectAPedia®   -   Search InspectApedia

Asphalt roof single tab sealant bleed-out staining on a Maryland roof © InspectApedia Bob SissonsAsphalt Shingle Asbestos
Asbestos in asphalt-based roofing shingles & felt underlayments

This article describes the use of asbestos in asphalt-based roofing products such as asphalt roof shingles and roll roofing, and also the use of asbestos in asphalt shingle siding.

We list the types of asphalt-based roofing products in which asbestos was used, we give known dates of manufacture, and we refer to research on the history of the use of asbestos in asphalt roof shingles, asphalt roll roofing, and related products.

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

Uses of asbestos in asphalt roof shingles, roll roofing, flashings, mastics

Thermal splitting asphalt shingle (C) Daniel FriedmanAsbestos was used in asphalt-based roofing products such as asphalt roofing or siding shingles in North America as early as 1891 and continued into the early 1980's.

The National Emissions Standards for Hazardous Air Pollutants (NESHAP) identifies several asphalt-containing roofing products that may also contain asbestos including

The following Table of Asbestos-containing Asphalt Roofing Products, adapted from Townsend et als (2007) lists what I call the "first order" producers of asbestos-containing asphalt roofing products.

Watch out: these are primary asphalt-based roofing product or material manufacturers.

The asbestos-containing asphalt or related materials produced by these manufacturers might well have appeared in other asphalt shingle brands or roll roofing brands, felt paper brands, and asphalt-based siding brands sold.

For example, a number common single brands sold in North America before the mid 1980's do not appear in this list but may have included products that contained asbestos.

Note: ... asbestos is rarely found in today’s roofing waste; however, one must still exercise caution in using PC waste, and mandatory testing of these materials for asbestos is required by some agencies. (Willis 2013)

Summary of Manufacturers of Asbestos-containing Asphalt Roofing Products

Roofing Manufacturer Years Produced Asbestos-containing Product
Barber Asphalt
Corporation
NA Asphalt-asbestos roof felt
Carey Manufacturing
Company
NA Asphalt-asbestos shingles, asbestos finish felt, mastic
Celotex
Corporation
1906 through
1984
Asphalt roof coating and other miscellaneous
materials
Fibreboard
Corporation
1920 to 1968 Roof paint, roll roofing with asbestos-containing base
sheets, caulking compounds, plastic cements, taping
and finishing compounds
General Aniline and
Film Corporation
1891 through
1983
Roofing asphalt
Johns-Manville
Corporation
1891 through
1983
Asphalt-asbestos shingles, rag-felt shingles, fibrous
roof coating, shingle tab cement, roof putty
Kaylite Company 1891 through
1983
Asbestos surface coating for shingles
National Gypsum
Company
1941 through
1981
Roofing and shingles
Monroe Company 1891 through
1983
Asbestos surface coatings for shingles
Rhone-Poulenc Ag
Company
Early 1930s
through 1976
Adhesives, coatings, sealants, and mastics
United States Gypsum
Company
1930 through
1977
Paper and felt

Notes to the table above

The most commonly-used asbestos fiber in roofing materials is chrysotile (Townsend 2007)

Townsend et als give this critical summary of the use of asbestos in asphalt roofing products that we have adapted with minor modifications. (Townsend 2007)

Source: Townsend, Timothy, Jon Powell, and Chad Xu. "Environmental issues associated with asphalt shingle recycling." Construction Materials Recycling Association, US EPA Innovations Workgroup (2007).

Excerpts from Townsend help interpret the table above:

Asbestos roof felt: Also referred to as asbestos roof mat, it is a component that is impregnated in asphalt that was used as an insulating and waterproofing material between roof boards and shingles (Johns-Manville no date). These roof mats were widely used in “built-up” roofs in the US (EPA 1990c). 

Asbestos roof putty: This was a plastic cement used to stop leaks due to holes in shingles, roofs, or slates (Johns-Manville no date).

Asbestos surface coating: This was a siding and roof coating designed for the application to exterior (and interior) surfaces of asbestos shingles, applied by spray or brush (Amianthus no date).

Mastic: A paste-like material used as an adhesive or seal 

In the 1970s, asbestos was banned from many uses when it became widely understood that workers who had been chronically exposed to the material developed cancer, asbestosis, and related diseases (NAHB 1998).

However, asbestos was not banned from all products, and available information indicates that some asphalt roofing products containing asbestos were manufactured after the 1970s.

According to the US Geological Survey (USGS), there has been no asbestos mining in the US since 2002, but asbestos is still imported and utilized in roofing products, totaling about 55% of the approximately 3,500 tons consumed in the US in 2007 (USGS 2007). The roofing products that still utilize asbestos include roof coatings, cements, and mastics (USGS 2007; Virta 2007).

According to the USGS and the Asbestos Information Association/North America (AIA/NA, an asbestos industry trade group), asbestos is not used in the production of asphalt shingles today, and was phased out as a material used in the production of asphalt shingles in the early 1980s (USGS 2007; AIA/NA 2007).

There are limited data available regarding the asbestos content used in roofing products, including asphalt shingles.

Manufacturer data regarding asbestos content in shingles is sparse, possibly because

(a) potential liability concerns,

(b) the companies that manufactured asbestos containing asphalt shingles no longer exist, or

(c) the data are simply not available.

Johns Manville Corporation, who began manufacturing asbestos-containing roofing products in the late 1800s, manufactured asbestos-asphalt roofing shingles (further described as asphalt impregnated asbestos-fiberglass reinforced shingles) from 1907 to 1979 that contained between 35 and 50% asbestos (EPA 1990d).

It is noted that this data may not necessarily be representative of the amount of asbestos used in the manufacture of asphalt shingles by others, but the data do indicate that the amount of asbestos used by some manufacturers was significant.

Typically, roofs are replaced every 12 to 25 years; however, it is not uncommon to install new roofing shingles on top of old ones, and as a result, roofing shingle waste may sometimes contain two or three layers of old shingles (RMG 2001). Despite this, one still may expect the occurrence of asbestos in discarded post-consumer asphalt shingles to decrease over time given that asbestos use in roofing products was mostly eliminated in the 1970s.

Asbestos is regulated by the US Environmental Protection Agency (US EPA) and the Occupational Safety and Health Administration (OSHA); EPA regulates the handling and disposal of asbestos (through standards known as National Emissions Standards for Hazardous Air Pollutants (NESHAP)), and OSHA regulates occupational exposure to asbestos.  

Asbestos & Metallic Micro-Meteorite Dust Test Results for Granular Debris from an Asphalt Shingle Roof

Roof granules from a Houston TX home tested for Asbestos (C) Daniel Friedman at InspectApedia.com

Photo: a collection of granular roof debris and dust examined first for metallic fragments and potentially metallic meteorite dust and later for asbestos.

[Click to enlarge any image]

Sample No. 10: Location: Houston TX, Asphalt shingle granular debris collected by homeowner, collected 07 April 2017 (by homeowner)

Below: these same roof granules under the stereo microscope in our lab. We also examined this sample in our lab, searching for mineral granules, potentially meteorite dust, following this note from the homeowner:

I ran a magnet through a little pile of shingle granules in the gutters, and found metal particles and flakes. Are there metal flakes, or any metal at all in the granule protective layer of asphalt shingles? Must know before I lecture on meteorites. ...

Roof granules from a Houston TX home tested for Asbestos (C) Daniel Friedman at InspectApedia.comI placed a strong magnet just above the shingles on my roof... no attraction. Then I scraped some of the granules off and tried the magnet... nothing. But when I ran the magnet through some granules that had collected in the gutter, I get many, many small pieces of ferrous metal.

This confirms something I read about the whole Earth being constantly bombarded by meteorites.

Most of them burn up in the atmosphere, but some survive as flakes and particles and land on rooftops (and on everything else, too). Imagine that -- being able to collect space material off your roof.

I've collected about an ounce of flakes and I'm going to give a lecture at my astronomy club on this subject on Friday. It will make an interesting school science project for kids..

We did find some iron (magnetic metal) debris in this sample, including a nail fragment visible in the photo below.

Reply to client:

In this sample I found debris that would adhere to my magnet but I had trouble, even at 1200x light microscopy, identifying shiny spherical objects. Most of what I found looked like rust flakes such as might have been shed by objects like the rusty nail fragment in the sample photo shown above.

And there are of course other metallic and magnetic particles used in asphalt roofing manufacture.

The metals found in roof shingle granules are most-often copper, zinc, or sometimes aluminum in coatings, included for algae resistance, reflectivity, or appearance. Among deliberately-used metals in asphalt shingle roofing manufacture, I'd be surprised to find magnetic or iron based particles.

However there are certainly going to be exceptions to what's common, and some magnetic metals including iron oxides might be used for color purposes, as I'll cite below.

Considering that experts had to search through 300 kg of roof dust and muck (collected over an un-specified interval) in Paris, Oslo and Berlin, using magnets to find just 500 cosmic dust grains, it seems to me that it will be difficult to reliably collect micrometeorites from most roof dust at most homes, particularly if the dust sample does not represent a sufficiently long collection interval.

Independent Lab Test Resutls for Asbestos in rooftop dust / meteorite sample

In 2019 we also sent this sample to a certified asbestos testing laboratory for characterization.

Report below: the EMSL Phase 1 test: Asbestos Analysis of Bulk Materials via EPA 600/R-93/116 Method using Polarized Light Microscopy found:

Asbestos test result for granular roof debris, Houston TX (C) Daniel Friedman at InspectApedia.com EMSL PLM

Positive identification of asbestos requires the determination of optical property characteristics of the six types of regulated asbestos: chrysotile, amosite (grunerite), crocidolite (riebeckite), anthophyllite, tremolite and actinolite asbestos. - EMSL

Report below: EMSL report on the same sample No. 010 using Asbestos Analysis of Non-Friable Organically Bound Materials by TEM via EPA/600/R-93/116 Section 2.5.5.1

Asbestos test results for Houston asphalt shingle roof granular debris (C) Daniel Friedman at InspectApedia.com EMSL TEM

For TEM, an aliquot of the material is organically reduced. This is performed on the sample by ashing (using a muffle furnace), followed by acid digestion to remove the carbonate mineral. Mass determinations are recorded after each step, determining the percent loss for each type of matrix material. - EMSL

Research on Metallic ingredients in asphalt roof shingles

Research on Use of Asbestos in Asphalt-based Roofing Products

Percent of samples of asphalt roof shingles found to contain asbestos - Willis - cited & discussed at Inspectapedia.com

 




ADVERTISEMENT





Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2023-11-06 by InspectApedia Publisher - do they still using asbestos containing roof felt or mastics right now?

@Anonymous,

NO. The Mesothelioma website that you quote makes a CONFUSING CLAIM when they state "Asbestos asphalt roofing compounds are still in use today, including coatings, cement, and mastics, according to Inspectapedia. "

What they say is technically correct, that is "in use today" can be taken to mean that OLD (made in 1984 or earlier) asbestos-containing materials might still be on a building roof.

But it is not the case that modern, new, asphalt shingles would be expected to contain asbestos.

Please read the article above - this page is our original article referred to by the mesothelioma website.

Here do NOT state that asbestos is still in use in the production of modern, contemporary asphalt shingle roof materials.

In this article we provide a table of the years that various manufacturers of roofing products produced materials containing asbestos.

None of those roofing manufacturing companies used asbestos in roofing products after 1984 and most discontinued the use of asbestos before that year.

What these dates mean is that if a U.S. building using asphalt roofing products such as shingles, roll roofing, or mastic flashing cement was built before 1984 AND if that building still contains roof materials from that time, then it is possible that asbestos-containing materials are indeed on the roof.

Because it's not at all likely that 1980's asphalt-based roofing products would still be in active use on a building as it's upper-most (exposed to weather) roofing, the most-likely scenario in which such products would still be in place on a roof would be as an older layer of roofing over which subsequent layers of roof materials have been placed.

Therefore the most likely asbestos hazard from such a roof might occur during building demolition or during a re-roof job or roof repair job that required tearing off (removing) all of the old layers of roof coverings and flashings.

Bottom line: Our article also includes this comment:

Note: ... asbestos is rarely found in today’s roofing waste; however, one must still exercise caution in using PC waste, and mandatory testing of these materials for asbestos is required by some agencies. (Willis 2013)

On 2023-11-04 by Anonymous

do they still using asbestos containing roof felt or mastics right now? I saw it was not banned in commercial use not sure about residential

do they?

www.lanierlawfirm [dot] com/mesothelioma/asbestos-exposure/products/roof-shingles/#:~:text=shingles%20are%20damaged.-,Is%20asbestos%20still%20used%20for%20roofing%3F,and%20mastics%2C%20according%20to%20Inspectapedia.

This website said asbestos use in asphalt shingles are still using and cited you guys, can you confirm if it is reliable?

- re-posted by moderator with link disabled

On 2023-08-21 by InspectApedia Publisher (mod)

@Anonymous,

Thank you for the added detail - that will help other readers.

On 2023-08-21 by Anonymous

@InspectApedia Publisher, they did the most of them, but i think some small dust are remaining and some very small pieces were still on the ground. i don't think it would be a problem as long as the shingles were installed after the asbestos were banned

the ground were very dark at during re-roofing process, but they cleaned it up after, just a bit remaining.

i am guessing it is installed after 2000, is this reasonable guess? what do you think

On 2023-08-21 by InspectApedia Publisher - part of a professional re-roofing job is that the contractor cleans up and removes the construction debris,

@Anonymous,

It seems to me that part of a professional re-roofing job is that the contractor cleans up and removes the construction debris, including shingle remnants.

On 2023-08-21 by Anonymous

@InspectApedia Publisher, the building was built 1920s, and the picture with shingles at good condition was 2011, the damaged one was taken 2022. so I don't think if it is really taking that fast for it to be damaged that much.

even it was installed at 2000, i doubt it can maintain in good condition until 2011. my guess is that it was installed not very long before 2011. Also not just the neighbor, many buildings in this area had shingles in good condition around 2011, but a lot of them were either replaced with new ones or damaged as in 2022.

the shingles were just replaced recently, i am worrying about the pieces remaining on the ground and some of them were still remaining on the roof and sometimes comedown along with rain and stick around my window, i do clear it once i see it, but just in case ,so I want to ask for your opinion, since i am not pro.

On 2023-08-21 by InspectApedia Publisher - can you identify the rough age of the asphalt shingles

@Anonymous,

Apologies, but the photo is a bit blurry and we have no surrounding/supporting information except that you seem to suggest that your building was built before 2000.

I agree that it's unlikely that a mid 1980's asphalt shingle roof would still be usable today and so yours is probably newer than that.

On 2023-08-21 by Anonymous

@InspectApedia Publisher, can you identify the rough age of the asphalt shingles, from what I knew at 2011 the shingles was looking in very good condition, but starting at 2018, there are some small rip offs at the edge for some shingles, and as it continues onto 2022 there were some granules missing and rain leaked.

i am guessing it is installed after 2000, i don't think asphalt shingles from before asbestos was banned can last that long judging by the speed it decays.

also the neighbor's house's shingle were also looking perfect at 2011 but at 2022 it is serverly damaged than the one on the picture, a lot of them having ripping off edges and lost of granules

asphalt shingles (C) InspectApedia.com Anon

...

asphalt shingles (C) InspectApedia.com Anon

On 2023-08-21 by InspectApedia Publisher

@Anonymous,

No. "The shingle itself" is the composite of all of its constituent parts. The "shingle" would not be a "shingle" if you took one or more of those away.

However asphalt-impregnated felt based shingles (older ones, that is) often contained asbestos fibers or fillers or both in the asphalt-impregnated base that forms the body of the shingles. The top coating of mineral granules were not generally an asbestos product.

On 2023-08-21 by Anonymous

@InspectApedia Publisher, are you saying the shingles itself doesn't contain asbestos?

On 2023-07-06 by InspectApedia Publisher

@Anonymous,

Found more likely in the asphalt-impregnated organic mat or substrate of the shingle; less likely in fiberglass mat based shingles.

On 2023-07-06 by Anonymous

@InspectApedia Publisher, were other types also used in rare case, or just none

was the use of asbestos in asphalt shingles common? if it does contain asbestos would every piece of the shingle contain asbestos?

On 2023-07-06 by InspectApedia Publisher - what type of asbestos was typically used in asphalt shingles

@Anonymous,

Chrysotile

On 2023-07-06 by Anonymous

what type of asbestos was typically used in asphalt shingles

Question: do I need to take more than one asphalt shingle sample to test my roof for asbestos?

Anonymous asked: Asbestos Content in Asphalt Roof Shingles

I can't find an answer, so I'm bothering you. Sorry.

I took a 4-inch sample from one of the ashphalt shingles coming off my roof to a lab for asbestos testing. I asked them if I needed to bring five or six samples and they said no, one is sufficient.
Do you agree?

... I had to get a new roof on my house. I'm certain the old roof was all the same shingles. I'm figuring they were 16 - 18 yrs old.

Anonymous by private email - 2019/01/12

Reply: no, not if all of the roof shingles are from the same brand, product, and epoch

Naturally I would tend to agree with the people you're hiring to do the "asbestos" test though without more specific information I'm unclear about why you are testing a modern
Asphalt roof shingles for asbestos.

IF you know that your asphalt roofing materials - such as asphalt shingles, roofing felt, roll roofing, were manufactured before roofing manufacturers in your country stopped using asbestos THEN you might treat the roof as "PACM" - presumed asbestos containing material, OR if facing extra demolition costs (because of PACM) you might want to have a sample tested.

If your home or its roof are in the United States and are newer than around 1985, the chances of asbestos in your asphalt roof shingles are pretty low. Only if a roofer used old roof shingle stock might that be expected.

But the lab cannot see your house, doesn't know its history, won't know the history of the roof, won't know if more than one brand, age, or shingle product is or was installed, and probably knows even less about asphalt shingle roofing practices or inspection.

So ALL that an asbestos lab is likely to tell you is whether or not they detected asbestos in the sample that you provided. They cannot take responsibility for sample selection or the sampling process. To have expert advice on sampling of a roof for asbestos you would need an on-site expert.

Or you can continue as a DIY project in which case it's up to you to know that your sample is representative.

Minnesota's DOH adds this advice

Just having asbestos siding and roofing on your home does not pose a hazard to your health. Asbestos-containing roofing and siding in good condition are best left alone. Damaged roofing and siding should be carefully repaired.

Sometimes asbestos-containing roofing and siding can be covered with new materials. Check your local building codes. www.health.state.mn.us/divs/eh/asbestos/homeowner/roofside.html

Watch out: demolishing asbestos containing materials without following proper procedures for containment and personal protection can be dangerous.

Given your report that your roof is about 18 years old, 2019 - 18 = 2001 = well after asbestos should have no-longer been found in asphalt shingles.

So your lab report would be very important if it finds asbestos.

Do let me know what your lab test reports as that will be helpful to other readers.

Reader follow-up: shingles tested negative for asbestos

The test was negative. The tar paper also. I think we're good.

The lab said asbestos is evenly distributed throughout individual shingles.

I asked if I should have brought 5 or 6 to test and he said no, one's fine. They said over the years, people bringing in multiple samples from the same roof always shared the same results.
This answer would have satisfied most people but ..


...

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

Or see these

Recommended Articles

Suggested citation for this web page

ASPHALT ROOF SHINGLE ASBESTOS 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

Or See

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING ROOFING

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.

Search the InspectApedia website

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

Comment Form is loading comments...

Citations & References

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



ADVERTISEMENT