Cob: White crystals> efflorescence

[Charmaine R Taylor]

Rosemary, sounds like efflorescence..a "blooming" of alkali salts on the
surface due to salts in the concrete blocks, or in the mortar mix, or landing
on the wall during rains, with acid rain being the modern culprit. .
This crystalization takes place when the salts which are soluable  get wet
and travel to the surface.   I will look up in my techie NLA report and see
what it says you can do besides scrubbing.

There is also a bit of information in the All About Lime book, pg 27, whcih
you have Rosemary.

Charmaine  Taylor
PO Box 6985, Eureka CA 95502
1-888-441-1632
http://www.northcoast.com/~tms
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Rosemary Lyndall Wemm wrote:

> Hi All!
>
> The rendered foundation boots of my cob shed have patches of white
> crystaline substance adhering to the surface.  Can anyone tell me what it
> is?  The concrete and brick tile surfaces are rendered with a mortor
> consisting of 6 parts sand: 2 parts red clay [which may have aluminium in
> it]: 1 part lime: 1 part grey cement + water to mix.
>
> - Rosemary
>
>  ---------------------------------------------------------------------
>  Rosemary LYNDALL WEMM,
>  B.Mus.(Inst.), T.S.T.C., B.A.(Hons), M.A.(Neuropsych.), etc.  _--_|\
>  Clinical Neuro-psychologist                             Perth/      \
>  Perth, Western Australia    lyndall at neurognostics.com.au  -->\_.--._/
>  ------------------- http://www.neurognostics.com.au ---------------v-