Asbestos in Plasterboard?

[noideamad]

The internal walls in my house are plaster board. I'll probably need to re-plaster some of the kitchen walls as part of the reno's I hope to do. The plaster is quite thick (8-10mm) and quite rough on the reverse side. Its quite powdery like plaster and has a hemp fibre through it much like old plaster cornice. Initially I wouldnt have thought there would be asbestos in it but everything I am reading is suggesting that almost everything built prior to 1982 would most likely have asbestos in it. Even in this plasterboard? - the house was built in the 50's.

[rod@plasterbrok]

It is not "plasterboard" it is fibrous plaster sheet. Now called plasterglass.

It will have ZERO asbestos in it.

[Bloss]

As Rod says - if it has plaster in it then it does not have asbestos.

Asbestos "fibro" sheeting is very hard and brittle, when old almost like stone or tile, and a grey/ green or blue/ grey colour (although when cut or drilled usually produces a whitish powder). Fibro was also usually no more than 6mm thick and often 4-5mm only - most plaster boards were 3/8" 10mm or even a little thicker.

What you describe is just the plaster sheeting that was made in factories all over the country before the paper covered plaster panels such as gyprock came on the market.

Might be hemp reinforced, but horse-hair was also quite common as was copra fibre - anything that was available and cheap.

Still wise to use a good mask when cutting, drilling, sanding or sawing plasterboard.

[Ashwood]

I'd agree with rod & bloss ... no asbestos in that. My place is exactly '50s, has the same thick plasterboard with the hemp/coconut pra fibre and powdery material when you break it.

The asbestos ones are thinner, brittle and if you see any broken pieces, you can see crystalline shaped material in the broken sections, a bit like microcospic-snowflakes.

[noideamad]

Thanks for the replies. Sounds like I can be confident about no Asbestos in my walls then, not the ones I want to remove anyway. Just need to determine whether my lino flooring has any in it now!

[Bloss]

Thanks for the replies. Sounds like I can be confident about no Asbestos in my walls then, not the ones I want to remove anyway. Just need to determine whether my lino flooring has any in it now!

In a domestic residence it would be highly unusual to have asbestos in the lino or vinyl flooring although pre 1984 it was common for asbestos sheeting underlay to be used - masonite hardboard underlay was more usual.

This is bound/bonded asbestos (AKA as fibro or compressed AC sheet) and is relatively safe - although all the usual precautions should be used if you decide to lift it or the overlying tiles. Removal and disposal of any asbestos would need to accord with your State's regulations. Any use of power tools or any disturbance that will create dust should be avoided.

Loosely bound asbestos was used under some brands of lino and vinyl tiles for commercial and industrial premises for short time in the late 50s and early '60s. It is very dangerous stuff as it emits airborne particles when disturbed.

There is no real reason to remove the tiles at all if you are in any doubt. Simply cover with new underlay and place your new finish over the top of that. It will be higher of course, but is a relatively common practice in renovations.

You should always wear good masks with filters (at least P2 paper, but full face silicone with twin canisters are better) when checking this stuff out. Tiny amounts of inhaled asbestos can do very great harm - and you won't know for 20-30 years by which time it is too late.

[noideamad]

Bloss, thanks for the info on lino. I wouldnt have thought that the lino covering would have had asbestos in it, however my concern is what is underneath the masonite. I have lifted some of the lino up, and it is masonite underneath. I also removed a piece of the masonite and there was a fibery substance under it? Not very thick at all, in fact not thick enough to really have any purpose at all, but still of some concern. It is a hairy/hemp like layer that has sort of stuck to the floor boards. Do you know of anything like this? I'll probably send a sample off and get it tested just for peice of mind, just curious in the mean time.

[totoblue]

Bloss, thanks for the info on lino. I wouldnt have thought that the lino covering would have had asbestos in it, however my concern is what is underneath the masonite. I have lifted some of the lino up, and it is masonite underneath. I also removed a piece of the masonite and there was a fibery substance under it? Not very thick at all, in fact not thick enough to really have any purpose at all, but still of some concern. It is a hairy/hemp like layer that has sort of stuck to the floor boards. Do you know of anything like this? I'll probably send a sample off and get it tested just for peice of mind, just curious in the mean time.

noideamad, you ought to read this thread
https://www.woodworkforums.com/showthread.php?t=20083
particularly the part about Noel Arnold and Associates who will do free testing (subject to conditions).

[Bloss]

Fair chance that the stuff under the masonite is simply hession - it used to be laid down and glued over to strengthen very old lino and sometimes rubber flooring laid directly onto floorboards.

Or simply the backing from the original lino that had adhered to the floorboards and was left there when the masonite underlay was put down.

No real reason or likelihood for it to be a dangerous substance and extremely unusual for it to be asbestos given your description.

If you are really concerned then getting tests done is always an option - but a costly one and since this is low risk site (IMHO) I doubt it is justified.

Asbestos is a dangerous substance when ingested as a dust or aerosol - so in that bound form I referred to earlier it is stable and so long you do not disturb it by drilling, sanding, filing etc and you follow standard simple safety procedures then you will be at little risk.

Since you already have good awareness of the issues then just go ahead and use your commonsense.

As you describe it I would be just laying your new coverings over the top of the exiting underlay unless it is breaking up or you need to remove it for some other reason.