InspectAPedia®   -   Search InspectApedia

Asbestos roof debris runoff after power washing (C) Daniel FriedmanAsbestos Cement Roof / Siding Power Wash Warning

  • POST a QUESTION or COMMENT about assessing the risk of damaged cement asbestos roofing and site contamination by asbestos fiber runoff after power washing a roof

Asbestos cement roof damaged by washing:

This article warns about un-supervised or un-trained environmental cleanup companies or work crews handling asbestos, lead, mold, and similar indoor contaminants, including identification of amateur or improper asbestos "abatement" projects that failed to properly remove materials or that left abandoned asbestos materials in place.

We also discuss certification & training for asbestos abatement, cleanup, or removal workers & companies, warnings about un-trained asbestos cleanup workers lack of training or job supervision result in improper asbestos, lead, mold and similar contamination removal efforts.

These warnings about using a power washer on an asbestos-cement roof also pertain to asbestos cement siding as well.

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

Asbestos Cement Roof Washing Troubles - "... they power-washed my asbestos cement roof ..."

Asbestos roof debris runoff after power washing (C) Daniel Friedman

Question: Is power-washed asbestos-cement roof runoff an environmental hazard?

I live in Brantford Ontario and a building in my neighbourhood has was I think is a corrugated asbestos roof.

Last weekend some workmen power washed it. The run off, when dried, looked like grey powder and lifted from the pavement in "sheets" almost like parchment paper.

I've attached a couple of photos. Does this present any danger or give cause for health concerns? - D.F., Brantford ONT

[Click to enlarge any image]

Reply: Asbestos hazards are probably present, asbestos regulation violations may have occurred, and further steps are needed

OPINION:

Most likely the debris that was washed off of the roof contains road and other environmental dust that had settled on the roof surface over time, and possibly algae, mold, or lichens that were staining the surface (as in our file photo of corrugated asbestos roofing - left) leading to the desire to wash the roof in the first place.

Asbestos roof debris runoff after power washing (C) Daniel Friedman

But because power washing is a strong approach to cleaning a surface it is likely to also have dislodged asbestos and cement particles from the asbestos-cement corrugated roof itself.

While wetting the material, something that would naturally occur during the power-washing of the cement-asbestos roof surface, would be expected to reduce the airborne level of asbestos during the actual washing process, although when properly performed, wetting to control asbestos particle release includes the addition of a wetting agent to the spray before it is applied.

Corrugated cement asbestos roofing

Power-washing a cement asbestos roof would leave substantial materials on the ground after the cleaning procedure. As the on-ground material dries asbestos fiber and particle risks are likely to be present.

So it would be no surprise if the debris on the ground around the building in your photos contains a high level of asbestos fibers and particles. The material therefore may form an airborne asbestos hazard in the neighborhood, or as it washes into local storm drains, it may constitute an illegal and improper disposal of asbestos dust and debris.

If the added cost to properly clean up this mess is going to be high (which we would guess is the case), it would be appropriate and inexpensive to collect a debris sample for testing by a local, certified asbestos testing lab to confirm that the contents are indeed contaminated at a level requiring professional cleaning.

In addition, power-washing the roof surface risks increasing the friable nature of the material that remains on the building, as the cementious binding has been removed from the uppermost roof surface, first by normal weathering and second, and much more aggressively, by the power washing process.

The building owners should address these questions immediately in order to reduce the spread and thus possible costs of a proper asbestos dust cleanup.

Asbestos regulations for Ontario are published under the Occupational Health and Safety Act and are in Ontario Regulation 278/05 and provide a clearly-written and comprehensive guide to cleaning up and disposing of asbestos containing materials in or on buildings. Discussing [Type 1] asbestos operations that regulation states:

1. Before beginning work, visible dust shall be removed with a damp cloth or a vacuum equipped with a HEPA filter from any surface in the work area, including the thing to be worked on, if the dust on that surface is likely to be disturbed.

2. The spread of dust from the work area shall be controlled by measures appropriate to the work to be done including the use of drop sheets of polyethylene or other suitable material that is impervious to asbestos.

3. In the case of an operation mentioned in paragraph 4 of subsection 12 (2), the material shall be wetted before and kept wet during the work to control the spread of dust or fibres, unless wetting would create a hazard or cause damage.

4. A wetting agent shall be added to water that is to be used to control the spread of dust and fibres.

5. Frequently and at regular intervals during the doing of the work and immediately on completion of the work,

i. dust and waste shall be cleaned up and removed using a vacuum equipped with a HEPA filter, or by damp mopping or wet sweeping, and placed in a container as described in paragraph 5 of section 15, and

ii. drop sheets shall be wetted and placed in a container as described in paragraph 5 of section 15, as soon as practicable after subparagraph i has been complied with.

6. Drop sheets shall not be reused.

7. After the work is completed, polyethylene sheeting and similar materials used for barriers and enclosures shall not be reused, but shall be wetted and placed in a container as described in paragraph 5 of section 15 as soon as practicable after paragraph 5 of this section has been complied with.

Watch out: in 2010 The New York Times reported that

65 to 80 percent of those receiving certification as qualified asbestos removal experts had not received the necessary training.

 




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 2022-07-20 by InspectApedia-911 (mod) - neighbor installing asbestos cement sheets on roof

@Chris,

If you want to have objective data in order to force some appropriate response or action, it might be a smart move to collect a sample of the material in your yard and have it tested by certified asbestos test lab.

If you do that, do keep us informed there may be able to comment further.

On 2022-07-20 by Chris

@InspectApedia-911, Hi Thanks for your advice. Can't see any asbestos debris around my garden, but the good news is that the person next door has changed the roof sheets for new cement ones. I must of got through to him. But I'm still worried about my garden? Thanks for your advice and a great service.

On 2022-06-09 by InspectApedia-911 (mod)

@Chris,

If you see actual white sludge, debris, or dust in or at your property you might take a sample to an asbestos test lab.

Without that objective data any guess would be so speculative as to be of little value.

On 2022-06-09 by Chris

@InspectApedia-911, Hi I remember about 20 years ago he removed it from a shed that he demolished and it's been in his yard till now. Do you think I should wear ppe when cutting my lawn or hedge Thanks.

On 2022-06-06 by InspectApedia-911 (mod)

@Chris,

Even if there's no asbestos, if one is drilling into fiber cement material you should not be breathing the dust.

Where do you think someone found asbestos cement roofing materials so long after its use has been banned?

On 2022-06-06 by Chris

@InspectApedia-911, Hi Thanks for your reply. I have spoken to this person next door and he admitted that it was asbestos roofing sheets he was putting up. After speaking to him he knows nothing about asbestos or wants to. He was on the roof drilling it to fix it , no mask or ppe. I just could not get through to him. Thanks .

On 2022-06-03 by InspectApedia-911 (mod)

@Chris,

Thanks, that's an interesting and reasonable question. I think that any cement-asbestos product exposed to the weather will shed at least some detectable asbestos particles and fibres that might be detected on the ground around and close to the building.

I haven't found objective data or studies reporting on wind-blown asbestos dust from asbestos-cement roofing onto neighbouring properties, though I expect that it's below the limits of detection except if the roofing is being demolished or disturbed,
OR
if the roof was power-washed and the power-washing debris was left on the ground nearby.

In the case you describe, the fellow putting up asbestos cement roofing next-door the dust hazard would arise from grinding, chopping, sanding, sawing the sheets in their current (new) location.

Are you really sure that the product is asbestos-cement roofing? In most countries that material has not been sold for decades now.

So if it's new material it's fibre-cement roofing but not asbestos-fibre-cement.

Post a photo of the work in process.

On 2022-06-03 by Chris

Hi please advise the guy next door is putting up asbestos cement roof sheets that have been jetwashed, previous to construction, will they continue to release fibres in the wind if they are not sealed. worried that they will be in my lawn and hedge that I need to cut. Please advise.

On 2020-08-27 by pressure washer

wet asbestos does not fly. if you see "dust" its water fog 99,9%. car brake pads have had asbestos in them so it is most likely that asbestos can be found from the roadsides all around the world.

On 2019-01-14 by danjoefriedman (mod)

Reader Anonymous wrote by private email:

am writing to see if you could offer me some advice?

I regular walk to work and on my route is a building with a corrugated asbestos cement roof and siding. It seems a small part of the siding has been cleaned at some point in the past. I looked on Google Street view and it has been cleaned for at least two years.

I walk on the opposite side of the road to the building, probably around 40-50 metres away.

Do you think there would be a health risk from this building? I don't know what method was used to clean the siding but power washing is a possibility.
- Anonymous 2019/01/11

Reply:

We just can't bet your health on making an environmental risk assessment by a brief e-text. There are just too many variables.

Actual roof composition, age, condition, method of cleaning, debris removed by cleaning asbestos content in debris, control of or disposition of roof wash-off debris, debris remaining in the area, conditions causing it to be airborne, distances, exposure level and duration, health vulnerability of people, etc.

Reader follow-up

Thank you for the response.

From looking at Google streetview, it would seem the siding must have been cleaned at least 10 years ago. The images show that the appearance has remained 'clean' since then.

I am guessing they must have used a sealer after cleaning it which allays my fears a bit.

Reply:

The measurable hazard (if there is one) would not be the roof it would be powdery residue or debris or dust containing asbestos in the roof wash-off.

On 2016-11-12 by Anonymous

Our neighbour has just power washed his garage roof sending asbestos all over our house and Garden. We are worried about our health and the cat we feel has long hair and should go into quarantine as she's been playing in it.....help!

I've searched the Internet and can't find anyone in the same position. We are upset and also angry but don't know what action to take or how to approach the neighbour. Help!


...

Continue reading at ASBESTOS ROOFING / SIDING DUST 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

ASBESTOS ROOFING / SIDING POWER WASHING 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