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Decramastic Roofing May Contain Asbestos (ACM)


Decramastic Tiles Asbestos


Some versions of mastic or bitumen based Pressed Metal Roof Tiles produced prior to the early 1980s contain asbestos.
Mastic or bitumen was the most common material used to adhere the stone chip to the pressed metal at that time.

All mastic or bitumen based Pressed Metal Roof Tiles should be suspected of containing asbestos until proven otherwise. Particular profiles which are likely to be affected include decramastic and early harveytiles, however other profiles may be affected.

Pressed Metal Roof Tiles manufactured by other parties are believed to have been introduced and manufactured after the ban on asbestos was implemented, but the same care should be taken regardless for any Pressed Metal Roof Tiles which may contain a mastic or bitumen based product.

The presence of asbestos can only be confirmed through sampling and testing by an accredited laboratory in accordance with the Health and Safety at Work (Asbestos) Regulations 2016 and the Approved Code of Practice: Management and Removal of Asbestos. A specialist company such as Hazmat should be engaged to undertake sampling, testing and remediation.

There are no risks associated with Pressed Metal Roof Tiles containing asbestos if they remain in good condition and are left undisturbed. A significant health risk arises when adhesive expires, stone chips become dislodged and asbestos fibres may become airborne and can be breathed into the lungs. This may occur if the tiles may be disturbed during maintenance, cleaning or removal.

Contact Hazmat for more information on 03 366-2262.

Decramastic-Roof suspect Asbestos (ACM)

40 thoughts on “Decramastic Roofing May Contain Asbestos (ACM)”

    1. Hi there Wayne,
      for buildings once Asbestos has been found to be present in Mastic, an asbestos survey and management plan needs to be performed by a company certified by a BOHS IP402 for example like HazMat. If found to be in sound condition, then simply follow the management plan to the letter.

      The Management plan is a living document which ensures Staff / customers / Tradespeople / occupants (if a residential dwelling/ rental property) are safe. For more information about surveys or Management plans call HazMat directly.

      If the survey displays that it is deemed a high risk factor then the best course of action could be for immediate safe removal and reinstatement of another roof by a licensed Asbestos removalist like http://www.hazmat.co.nz.
      Any Licenced company performing a removal should be providing you with a third party assessor clearance certificate which shows the work has been done properly and is safe for re-occupation. For any further information please contact your Local Hazmat Expert

  1. Hi
    If my roof sample comes back positive for asbestos and I am advised to replace it, does the removal affect the insulation in the ceiling?

    1. Hi there Rebecca, depending on how the removal is done and whether or not sarking or building paper is underneath the roof and also if polythene or suchlike is laid to protect it during removal, it may be able to be saved. In reality, best practice and safety usually dictates replacement. Welcome to call us to discuss.

  2. Shirley-Ann Crosby

    Have just found out that my unit has tiles with asbestos in them.
    Can you please advise what my next step is? Who do I need to approach to remove these since my roofer says he cannot.

  3. Hi, wondering if you could advise whether decramastic tiles containing asbestos can be resurfaced/repaired once they have started to rust, or if they have to be replaced. Thanks.

    1. Hey There Kristy, Thanks for the enquiry.
      You did not mention if this was the entire roof that is now nearing this point or a few trouble areas. I will give you advise on both.
      Whole Roof:
      Like most materials, once compromised by rust or weathering, you need to recondition a substrate back so that it can be recoated / painted / remedied. Unfortunately when this material contains Asbestos, Worksafe does not recommend the usual methods of cleaning and preparing a surface for paint/glue/adhesives like scraping, waterblasting, sanding, grinding etc. Therefore I am yet to see a great example of what you can do to recondition an entire roof properly to give you longevity. Decramastic Tiles is one of the few products which does not take well to using encapsulants and membranes as it is gritty. Suggest A Reroof. CONTACT HazMat for a quote for this.

      In the case of point repairs, you may be able to remedy by replacing a line/row/tray using a qualified roofing company with appropriate PPE. I would not attempt this yourselves unless you know what you are doing, the way Decra is put down, it can be tricky. Hope that helps?

  4. I was having some work done on my roof. The company water blasted the roof and removed a lot of the gritty coating before an asbestos test was conducted. It came back positive (Chrysotile).
    My question is the grit that has been left on the ground from the pressure washing a potential hazard ? or would the asbestos be contained within/under the tiles still on the roof?


    1. Hi there Scott, Yes the grit/chip was originally on the roof held together by the mastic/resin/glue which is what contains the asbestos fibres.
      If the grit/chip has been removed residues will still remain on it. This is still very much a contamination issue as I am assuming the area has not been cleared by an assessor. When we remove decramastic roofs (which we do many) in order to gain our asbestos clearance certificate from a third party assessor we must ensure all loose material from interior of roof cavity/ground/spouting etc is vacuumed and removed accordinly. BTW High pressure systems are banned from being used to clean asbestos Decramastic tiles. Hope this helps.

    1. Hi there, sorry we are not qualified to help you on this, in the first instance speak with AHI or chat with a lawyer on options.
      I am not aware of any cases where a claim has been successfully achieved.

    1. Hi there, HazMat are not qualified to give you any advice in this area.
      There has been other cases where damages have been sought from other providers of asbestos containing material.
      See information to this link on wikipedia here https://en.wikipedia.org/wiki/James_Hardie_Industries

      “Asbestos products and controversy
      See also: Wittenoom Gorge, Western Australia
      In 1978 the effects of pleural abnormalities and other asbestos-related diseases were beginning to show up in the former mine workers. Journalist Catherine Martin’s front-page story for The West Australian won a Walkley award and she produced a series of another nine articles highlighting the impact on workers and their families. Martin was made a Member of the Order of Australia on 12 June 1982 for services to journalism.

      While other companies were involved in similar asbestos-related activities, most notably CSR Limited, more than 50% of claims made to the NSW Dust Diseases Tribunal in 2002 were brought against companies in the James Hardie group.[10] Prince et al. claim that this is due to the range of mining and manufacturing interests that James Hardie had throughout its long operating history.[10] The Australian Council of Trade Unions has estimated that 4600 claims for mesothelioma would be made against James Hardie from 2006 onwards, with claims expected to peak in 2010 or 2011 at 250 per year. The total number of past and future claims made against James Hardie for asbestos-related diseases is estimated to be more than 12,500, of which 8103 will be claimed after 2006.[7]

      Bernie Banton AM was the widely recognised face of the legal and political campaign to achieve compensation for the many sufferers of asbestos-related conditions, which they contracted after working for James Hardie. Bernie Banton suffered from asbestosis, pleural mesothelioma and Asbestos-Related Pleural Disease (ARPD), which required him to carry an oxygen tank wherever he went.[11]

      James Hardie and its subsidiaries had been providing compensation for victims of its operations since the 1980s. Though some earlier claims had arisen, the proliferation of cases from the 1980s onwards forced James Hardie to acknowledge that it had known asbestos to be dangerous. James Hardie nonetheless maintained that it had done everything possible to protect workers.[12][13] In 1978 the company began putting warning labels on its products explaining that inhalation of the dust could result in cancer[14] and in March 1987 James Hardie ceased all asbestos manufacturing activities.[15]

  5. Hi,

    Is there a possibility that there could be asbestos in Decramastic Tiles for a house built in the late 1990s like around 1998?



    1. Hi there Colin, given the AHI / RANZ Roofing Association of NZ statement, I would think not, the dates it gave was prior to early 1980’s. I would confirm with the manufacturers and if still in doubt we recommend you get them tested.

  6. We live in a semi rural area with a water tank. We could possibly have a roof which has tiles deteriorating and it is suspected that the asbestos glue was used originally to coat the tiles. If this is the case and we have to replace the roof, what is the pisition with the water tank? Would we need to replace this as well?

    1. Hi there Jane, thanks for the question.
      When you say water Tank, I am assuming you mean you are relying on water from your roof feeding into your water tank.
      Any foreign contaminant (including the glues, asbestos, fill and bitumen) cannot be good for you.
      There are many conflicting research documents and information about whether asbestos fibres in drinking water has a direct link to other cancers.
      I will not be drawn into this knowing the amount of asbestos pipe that is still feeding water into our homes in suburbia Wellington.
      1st – Get it tested, and make a plan from there. If you are in greater Wellington we would be happy to help.

  7. Justine de Spa

    I have just had my Decramastic roof repaired and it looks great. The tiles were very worn, some parts had lost their coating entirely, they were dented, some were beginning to crack, rust etc…&a building inspection suggested a professional assessment.
    My roofer was brilliant, he has had 3o+ years experience. He knew without testing they would contain asbestos in the adhesive & so could not waterblast them to clean them for resurfacing [now illegal] he applied Moss killer one day,then encapsulated the entire roof the next. It was then safe to repair damage, then he applied 3 coats of new adhesive and a layer of chip. The roof is guaranteed for 15 years but will last longer [he says]. This was much more cost effective & environmentally friendly than removal.

    1. Hi there Justine,
      I am glad you are happy with the results.
      Yes, some decramastic roofs, if in a good state of repair, may be able to be safely remedied in this way.
      As long as the applicators has had suitable training around working with Asbestos keeping his workers, homeowner (PPE, face fitted masks, coveralls etc) and treated by double bagging and disposing of all material coming off the roof as hazardous and taken to appropriate Asbestos hazardous waste landfill. The Environmental effects of toxic products and Asbestos running off into the stormwater drains, poisoning streams etc must be avoided at all costs. As too with just throwing out any waste with general waste is a hazard.
      Be aware that Moss killers generally take many months to activate properly before being effective so having applied one day and then coating on top the next, may not be the best course of action. We have tried many types of industrial moss killer to treat moss growing on fibre cement asbestos roofs / claddings and generally we see the moss starting to fall away months after the application. Your roofer of 30 years may be using a product that the roofers and suppliers we work in with, are not aware of.
      In terms of cost effective, the thing to bear in mind is when it comes to resale, you still have a roof that you will need to disclose to potential buyers that it may contain asbestos. In terms of a safe, when it deteriorates again in the future, it will become a hazard again.
      Please feel free to post again for a followup on how your roof is performing in the future. Thanks for sharing.

  8. Geoff & Anne Haycock

    My 1960’s decramastic roof was cleaned and resurfaced with grit added about 8 years ago and it is still in good order. I am considering replacing it with long run iron. It has asbestos in it the test results show .01g per 7.34 g sample. Would the existing tiles be able to be removed without the full asbestos procedure recommended for decramastic roofs?

    1. Hi there Geoff, RANZ tried to seek an exemption to allow roofers to deal with decramastic roofing as the % of asbestos is lower than some other building products. However, they were not granted it.
      The % does not matter. One fibre in your lungs is enough to do the damage,therefore the full asbestos procedure done by worksafe licensed removalists must be followed. This is to ensure safety of workers, occupants and neighbours.

  9. Hi, we are first home buyers looking at buying a house built in 1985 with a decramastic pressed metal tile roof and textured ceilings in the bedrooms. The roof is past its warranty and may be due for a replacement. Although the owners and their builder says they are 99% sure there is no asbestos, is this to be trusted? Are we being overly cautious where we shouldn’t be? Is there any chance of the roof and ceiling containing asbestos?

    1. Hi there Anne, even though their builder and they believe it not to contain Asbestos, I would still have it tested.
      Yes, we have found traces of asbestos in ceiling and roof cavities when there has been an Asbestos Roof or asbestos backing board underneath corrugated iron.

  10. Hi looking to purchase a 1974 house (126m2) with decramastic roof which has seen better days. Ball park figure, how much should i be allowing for roof replacement with colour steel and new guttering, given that roof is likely to contain asbestos? Cheers

    1. Hi there Hannah, Thanks for the enquiry, we will need to know a lot more information to be able to give you an estimate. If you are in Wellington call Chris on 0275842729 or Canterbury call Shane on 021399247. cheers

  11. Hi. My wife and I are social housing tenants. Our decramastic time roof has leaked for over a year. The social housing provider has told us the test was positive for asbestos. Edwards and Hardy are coming to replace the roof. We now have scaffolding so I went up to clean gutters and sure enough the tiles shingle are all coming apart.
    Does the removal work need to be done by a company like yours ?
    So far the landlord has not been responsive to our request for explanation.
    Kind Regards Jonathon

  12. Our house was built in the late 60s with a stone chip corrugated iron roof. Do you know of any issues with asbestos materials used with corrugated iron? All the web sites I visit refer to roof tiles.

    1. Unsure what you mean by stonechip corrugated iron.
      Yes most of the literature refer to pressed metal tiles as it was well documented that in some there was Asbestos found in the Mastic (glue) of what held the chip affixed to the iron. These were known as decramastic tile. I would recommend getting it tested as there is a chance a similiar mastic/glue was used.

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