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GSBN: Digest for 12/7/01



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-> Construction en Blocs de Terre Comprimee
     by "Rob Tom" rw_tom@...
-> YakWoman asks about Lime (FWD)
     by "Rob Tom" rw_tom@...
-> GSBN: Lime and Cement Plaster
     by "Frank & Ingrid" strawbales@...
-> 1:1:6, Lime:Cement: Sand, okey dokey in Capitola
     by Kelly Lerner klerner@...
-> More on lime
     by Kelly Lerner klerner@...
-> Re: GSBN:Lime and Cement Plaster
     by matts a myhrman biwb@...


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Date: 7 Dec 2001 20:08:31 -0600
From: "Rob Tom" rw_tom@...
Subject: Construction en Blocs de Terre Comprimee

on 6 Dec 2001 13:01:09 -0600
Athena and Bill Steen absteen@... wrote:
Re: GSBN:Fwd: French translator needed!
>
>When I get it copied I shall.

[a bazillion bytes of unnecessarily repetitive material from a gazillion 
responses <snipped>]

Boy, if I ever see Beel you can be sure I'm going to make him write 1000 
times on the chalkboard, :

     "I will remember to <snip> redundant material when responding to 
messages sent to the GSBN List"

I'm not sure what Beel has but for those who are able to read en francais, 
you may be interested in a somewhat related document from May 1999, a report 
from Canada Mortgage and Housing Corp. (CMHC) entitled :

    "Construction en blocs de terre comprimee "
         by  Ginette Dupuy, B.Arch, M.Sc.A.

It provides test data for 5 different earthen mixes
with properties including :

         (i) densite
        (ii) conductivite
        (iii) resistance thermique
        (iv) chaleur massive
        (v) gel et degel
        (vi) permeabilite
        (vii) absorption de l'eau
        (viii) resistance en compression (blocs)
        (ix) (resistance en compression (prisms)

The cost of the report is $10 for non-Canadians (I think)
and may be ordered by sending a message to the Canadian Housing Information 
Centre (CHIC) at CMHC.

       chic@...
       or on the web
       http://www.cmhc-schl.gc.ca
       or telephone
       1-800-668-2642

If someone here is willing to translate it into English, I suspect that the 
people at CMHC wouldn't mind at all if the translation were to be made 
available to all who are interested (ie all the people on this List) but it 
might be a good idea to get CMHC's "OK" first. CMHC didn't bother 
translating the original because they suspected that the demand for the 
report would be minimal. It'd be nice to prove them wrong.


  --- * ---
Robert W. Tom
Kanata, Ontario, Canada
rw_tom@...

please visit:  http://www.theHungerSite.com daily



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----------------------------------------------------------------------

Date: 7 Dec 2001 20:09:28 -0600
From: "Rob Tom" rw_tom@...
Subject: YakWoman asks about Lime (FWD)

The following is a response from Harry Francis, probably the most 
knowledgable "Limey" in North America. You may recall that 'Arry contributed 
to the "Lime Plaster" issue
of The Last Straw last year, which Athena and Beel Steen guest-edited.


- --------- Forwarded message ----------
From: CALXA@...
To: archilogic@...
Cc: klerner@...
Date: Fri, 7 Dec 2001 11:39:50 EST
Subject: Re: YakWoman asks about Lime

Kelly,

I think Tom is corrrect...either his mix or your propposed mix will work 
fine. I think the contractor is used to using cement for stucco work, and 
just a little lime to make it more plastic ( workable). (This is typical of 
today's need to get it finished quickly mentality).

The 1:1:6 will work fine, I think, but will be slower setting, than  his 
suggested mix...


The main idea here is to use as little cemnetiscous materials as possible 
(lime and/or cement) and as much sand as the cementiscous materiaqls will 
hole. The reason is that the heat expansion of sunlight striking the walls 
can result in cracks if the materials do not expand uniformally. Literature 
says that lime/sand mixes crack less because the expansion of the lime and
the sand are about equal....whereas the cement expands at a different 
rate...causing cracks.


Cement is often caustic, causing burns of workers hands, etc.  Quicklime is 
also caustic...not due to the chemistry, but due to the heat generated when
hydrated ( mixed with water). The resulting hydrated lime is not caustic 
unless additives have been added making it so...

His concerns about your mix being too hot - caustic - may result from 
experience in slaking quicklime. If the hydrated lime is thoroughly soaked 
and aged 24/48 hours before using in the mix, any un-hydrated quicklime
will be hydrated and no heat generated.

However, the portland cement will produce sufficient heat on hydration to 
cause burns, and many Portlands have sufficient sodium hydroxide contained 
to
make it chemically caustic..and result in chemical burns....to the skin and 
eyes...

The old literature suggests 1:3 ratios  cementiscous material to 
sand.....with comments to sue as much sand as the stucco will carry....to 
prevent thermal  expansion cracking.

The contractor may dislike the slow setting of pure lime stuccos, and the 
1:1:6 does help the mix harden quicker...and the specific sand used makes
the difference in ratios needed to make a satisfactory project.... the old 
NLA handbook suggests no more than 20 % Portland cement be added

"Cement, however,  should not be added in excess of 20% of the lime used."

"Then, too, after the lime has hardened it has practically the same heat and 
moisture co-efficients of expansion as does the sand it bind in place."


Kelly, I hope these comments help in your negotioations with the 
contractor...Admititily, many projects today, are simply Portland cement and 
sand, with just a little lime as a plasticizing agent...resulting is short
life, cracks, debonding, etc... and a bad name for stucco....What A 
shame....


Harry
======= End of Forwarded Material =========

  --- * ---
Robert W. Tom
Kanata, Ontario, Canada
rw_tom@...

please visit:  http://www.theHungerSite.com daily



_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp



----------------------------------------------------------------------

Date: 7 Dec 2001 20:14:06 -0600
From: "Frank & Ingrid" strawbales@...
Subject: GSBN: Lime and Cement Plaster

Greetings Kelly and all,

not being an advocate of cement render at all, I still have to agree with
Kelly's plasterer contractor. He is basically using the traditional cement
render mixture. I have rendered with that recipe in Europe and Australia
alike.

The important question really is, why do we need lime in a cement render at
all? There is only two reasons why we need to add lime. 1) without lime, the
mix will not stay homogenous, it will separate into its components (sand on
the bottom/cement in the middle/and water on top) and needs constant mixing
to avoid this separation.  2) lime makes the mix creamier and easier to
apply. A small amount of lime, such as suggested by Kelly's plasterer, will
actually perform these tasks already. Using the smaller amount of lime, as
in the suggested mix of 1 bag cement, 1/4 bag lime and 25 shovels of sand,
will not diminish vapour permeability, because the sand is responsible for
that. Adding more lime may even result in less permeability, because the
lime particles are much finer than the cement and sand particles, and clog
the oxygen pockets of the render.

If you are worried about a hot mix there are actually some clay products you
can use (instead of lime) to keep the mix from separating into its
components. In Australia these are called Plaster Master, Builders Clay or
Renderers Clay and are usually available in 25 kilo bags. This clay will
help keep your mix homogenous and you don't have to worry about lime burning
anything. It costs about the same than hydrated lime (or even less) and is
easy to work with. You can use it as the same mix (as above), that will work
fine and will not affect permeability unfavourable.

We have actually not rendered with cement for several years, thankfully clay
and lime renders are very well received in Australia. I used to hate working
with cement render, it feels dead and is not very pleasant on the skin no
matter how much lime is in it.

I hope I have not confused anyone and good luck with the project.

Regards, Frank Thomas


Please view this website
http://www.members.sia.net.au/tgibson/strawbalesite/index.htm for an
introduction of one of our projects.



----------------------------------------------------------------------

Date: 7 Dec 2001 21:37:47 -0600
From: Kelly Lerner klerner@...
Subject: 1:1:6, Lime:Cement: Sand, okey dokey in Capitola

Hi all,
Thanks to all of you who replied to my query. Typically, it turned out to 
be a simple miscommunication. I told the general contractor 1part lime:1 
part cement:6 parts sand and she told the plaster sub, 1 bag of lime, 1 bag 
of cement and 6 shovels of sand. When I talked directly to the plaster sub 
we had it worked out in a few minutes.

He'll be using 1 bag of lime (hydrated, type S): 1 bag of cement and 36-40 
shovel of sand. A bag is approximately 6+ shovels (add that to conversion 
tables). Now if I can only find some nuns...

For all those who mentioned earth - I too prefer earth plaster inside and 
out, but because of the budget, the schedule, the weather here (rainy) and 
a lack of contractors who can work with earth plasters, we're using the 
lime/cement/sand mix on the exterior.

I'm doing all the interior earth plastering (4 plus rooms of earth over 
straw-bale and over sheet rock ). Nice to get out of the office, but I'm a 
little sore... I'll have about 40 work party volunteers over the weekend to 
focus on the straw-bale walls. Using a 1/2" screened local clean fill-dirt, 
the mix is 1 part water: 4 parts clean fill: 2 parts sand and 3 parts 
chopped straw.

Thanks again, it's nice to know there's a knowledgeable community out there,

Kelly 



----------------------------------------------------------------------

Date: 7 Dec 2001 21:52:44 -0600
From: Kelly Lerner klerner@...
Subject: More on lime


Hi all,
I received this excellent explanation from Harry Francis that you all might 
want to print out and put in your lime folder (and you should all have a 
lime folder if you don't already). Highlight for me was to know that lime 
and sand have a very similar coefficient of expansion. STOP cracks now - 
use more lime.
Toodaloo,

Kelly

>The 1:1:6 will work fine, I think, but will be slower setting, than  his
>suggested mix...
>
>
>The main idea here is to use as little cemnetiscous materials as possible (
>lime and/or cement) and as much sand as the cementiscous materiaqls will
>hole. The reason is that the heat expansion of sunlight striking the walls
>can result in cracks if the materials do not expand uniformally. Literature
>says that lime/sand mixes crack less because the expansion of the lime and
>the sand are about equal....whereas the cement expands at a different
>rate...causing cracks.
>
>
>Cement is often caustic, causing burns of workers hands, etc.  Quicklime is
>also caustic...not due to the chemistry, but due to the heat generated when
>hydrated
>( mixed with water). The resulting hydrated lime is not caustic unless
>additives have been added making it so...
>
>His concerns about your mix being too hot - caustic - may result from
>experience in slaking quicklime. If the hydrated lime is thoroughly soaked
>and aged 24/48 hours before using in the mix, any un-hydrated quicklime will
>be hydrated and no heat generated.
>
>However, the portland cement will produce sufficient heat on hydration to
>cause burns, and many Portlands have sufficient sodium hydroxide contained to
>make it chemically caustic..and result in chemical burns....to the skin and
>eyes...
>
>The old literature suggests 1:3 ratios  cementiscous material to
>sand.....with comments to sue as much sand as the stucco will carry....to
>prevent thermal  expansion cracking.
>
>The contractor may dislike the slow setting of pure lime stuccos, and the
>1:1:6 does help the mix harden quicker...and the specific sand used makes the
>difference in ratios needed to make a satisfactory project....
>
>the old NLA handbook suggests no more than 20 % Portland cement be added
>
>"Cement, however,  should not be added in excess of 20% of the lime used."
>
>"Then, too, after the lime has hardened it has practically the same heat and
>moisture co-efficients of expansion as does the sand it bind in place."
>
>
>Kelly, I hope these comments help in your negotioations with the
>contractor...Admititily, many projects today, are simply Portland cement and
>sand, with just a little lime as a plasticizing agent...resulting is short
>life, cracks, debonding, etc... and a bad name for stucco....What A shame....


======================================================
Kelly Lerner
One World Design, Design and Consulting
925 Avis Drive
El Cerrito, California, 94530, USA
klerner@...   <http://www.one-world-design.com>
510-525-8582 phone, 510-528-8763 fax
======================================================



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There may be important message content
contained in the following MIME Information.
********************************************


- ------------------ MIME Information follows ------------------

- --=====================_3142210==_.ALT
Content-Type: text/plain; charset="us-ascii"; format=flowed

<<<<<< See above "Message Body" >>>>>>

- --=====================_3142210==_.ALT
Content-Type: text/html; charset="us-ascii"

<html>
Hi all, 
I received this excellent explanation from Harry Francis that you all
might want to print out and put in your lime folder (and you should all
have a lime folder if you don't already). Highlight for me was to know
that lime and sand have a very similar coefficient of expansion. STOP
cracks now - use more lime. 
Toodaloo, 
 
Kelly 
 
<blockquote type=cite class=cite cite>The 1:1:6 will work fine, I think,
but will be slower setting, than  his  
suggested mix... 
 
 
The main idea here is to use as little cemnetiscous materials as possible
(  
lime and/or cement) and as much sand as the cementiscous materiaqls will
 
hole. The reason is that the heat expansion of sunlight striking the
walls  
can result in cracks if the materials do not expand uniformally.
Literature  
says that lime/sand mixes crack less because the expansion of the lime
and  
the sand are about equal....whereas the cement expands at a different
 
rate...causing cracks. 
 
 
Cement is often caustic, causing burns of workers hands, etc. 
Quicklime is  
also caustic...not due to the chemistry, but due to the heat generated
when  
hydrated  
( mixed with water). The resulting hydrated lime is not caustic unless
 
additives have been added making it so...  
 
His concerns about your mix being too hot - caustic - may result from
 
experience in slaking quicklime. If the hydrated lime is thoroughly
soaked  
and aged 24/48 hours before using in the mix, any un-hydrated quicklime
will  
be hydrated and no heat generated.  
 
However, the portland cement will produce sufficient heat on hydration to
 
cause burns, and many Portlands have sufficient sodium hydroxide
contained to  
make it chemically caustic..and result in chemical burns....to the skin
and  
eyes... 
 
The old literature suggests 1:3 ratios  cementiscous material to
 
sand.....with comments to sue as much sand as the stucco will carry....to
 
prevent thermal  expansion cracking.  
 
The contractor may dislike the slow setting of pure lime stuccos, and the
 
1:1:6 does help the mix harden quicker...and the specific sand used makes
the  
difference in ratios needed to make a satisfactory project.... 
 
the old NLA handbook suggests no more than 20 % Portland cement be added
 
 
"Cement, however,  should not be added in excess of 20% of the
lime used."  
 
"Then, too, after the lime has hardened it has practically the same
heat and  
moisture co-efficients of expansion as does the sand it bind in
place." 
 
 
Kelly, I hope these comments help in your negotioations with the  
contractor...Admititily, many projects today, are simply Portland cement
and  
sand, with just a little lime as a plasticizing agent...resulting is
short  
life, cracks, debonding, etc... and a bad name for stucco....What A
shame....</blockquote>

<b> 
</b>====================================================== 
Kelly Lerner  
One World Design, Design and Consulting 
925 Avis Drive  
El Cerrito, California, 94530, USA  
klerner@...  
<<a href="http://www.one-world-design.com/";
eudora="autourl">http://www.one-world-design.com</a>> 
510-525-8582 phone, 510-528-8763 fax 
====================================================== 
</html>

- --=====================_3142210==_.ALT--



----------------------------------------------------------------------

Date: 7 Dec 2001 23:21:19 -0600
From: matts a myhrman biwb@...
Subject: Re: GSBN:Lime and Cement Plaster

Kelley,
Matts and I have just completed the second coat of a 1lime:1cement: 7sand
mixture on our strawbale wall across the fronts of our two houses.  No
problem to any of the five applicators, except dry skin.   Hugs.
Judy

Judy Knox and Matts Myhrman
Out On Bale
Tucson, Arizona  

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