Asbestos Cement Roofing

[Rob. B]

Hi All,

I have some asbestos cement roofing in my shed that someone has cut to length internally in the past (so you can see the asbestos in the middle) so that the sheets overlap each other.

Is this safe? I.e is the asbestos loose or is it still bonded with cement in the middle?

It has been tested in the past and has got some blue asbestos (as well as white) in it.

It is a timber framed shed so I am a bit concerned that if there is any vibration lots of fibres are going to be released.


Thanks,

Rob

 

[Blagard]

I would not be happy with any known asbestos sheet that has been cut or broken. The fibres are sealed at the original sheet edges, not where it is cut, broken or drilled. I don't know if you can paint anything to such a cut or if it is even safe to attempt that.

My own local authority will accept sheets suspect of having asbestos content providing they are double wrapped in 1000 gauge plastic sheet taped up. Removing it is a question of removing the fixings and the sheets whole without further breaking or cutting.

See
http://www.hse.gov.uk/pubns/guidance/a14.pdf

 

[Rob. B]

I would not be happy with any known asbestos sheet that has been cut or broken. The fibres are sealed at the original sheet edges, not where it is cut, broken or drilled. I don't know if you can paint anything to such a cut or if it is even safe to attempt that.

My own local authority will accept sheets suspect of having asbestos content providing they are double wrapped in 1000 gauge plastic sheet taped up. Removing it is a question of removing the fixings and the sheets whole without further breaking or cutting.

See
http://www.hse.gov.uk/pubns/guidance/a14.pdf

So the fibres in the middle are loose then? I thought that the sheets were an asbestos & cement mix sandwiched in between cement

 

[Blagard]

I would not go so far as to say they are loose, your description is OK but the fibres at cuts and breaks are disturbed so there is a potential release of some fibres in such situations. If you want to live with the risk however small that is up to you. If you plan to use machines in your shed that generate vibrations again that is not going to help is it. I know of plenty of garages that still have suspect sheeting as roofs and left well alone I would not be concerned as they only get used for storage.

 

[Lower]

It's the cutting or drilling that releases the fibres. They don't start 'escaping' through the cut after the cut has been made. The asbestos is bonded with cement throughout the sheet in exactly the same way that sand is in cement.

Personally, I wouldn't worry about it.

 

[pilsbury]

As I understand, Asbestos cement sheet roofing isn't really a problem unless you sand, cut, drill or burn it. Even then, it is only a danger at the time whilst fibers can be released. In addition, out of all the ACM, cement bound asbestos is the least likely to release fibers as it is bound in cement making the individual asbestos fibers heavy and hard to get airbourne. The fiberous pipe lagging is the worst.

If it was cut in the past I would say that there is very little risk indeed. To go belt and braces, you could paint some bituminous paint on the edge although I wouldn't bother.

 

[datarebal]

1. get it stripped and replaced
2. Paint it as suggested
3 put up a separate ceiling fully seal the edges