[GSBN] "Dipped" plaster - Straw Bale buildings

[Andy Horn]

Hi Andre

I could not agree with you more with what you have said, that “you need to
drive the plaster into the bales” I suppose I am wrong to use the word
dipped bales, because once the bale is in or above the “dipping tank” or
bath filled with a yogurt like consistency of earth, we take wooded stakes
i.e. cobbing sticks – and force the slip plaster right into the straw.....so
it is never a simple case of just dipping the bales.

 

As opposed to trying to get the plaster on the bales vertically, by taking a
watery plaster and pouring it from above into your bales positioned above
the dipping tank / bath at a comfortable working height and forcing it into
the bales with a cobbing stick I have found it to be an easy way of getting
a seriously solid clay coating.....typically a minimum penetration of about
80mm. We don’t have such extreme cold so I don’t mind exchanging a bit of
insulation for added thermal mass. We then half dry the bales off until they
stiffen up into the consistency of cob. We then take these “cob-bales” (like
giant bricks of cob) as i like to call them and stack, compact and fix them
onto the walls with a combination of vertical and horizontal staking. We
then immediately begin to work the walls with a cobbing stick and adding on
the plaster. It is quite labour intensive, but a whole lot faster and makes
for very solid walls.

 

See photos and text of some of the process at:
<http://www.facebook.com/media/set/?set=a.555753287791955.1073741825.1903721
04330077&type=3#!/photo.php?fbid=563405057026778&set=a.555753287791955.10737
41825.190372104330077&type=3&theater> 

http://www.facebook.com/EcoDesignArchitects.and.Consultants#!/media/set/?set
=a.555753287791955.1073741825.190372104330077
<http://www.facebook.com/EcoDesignArchitects.and.Consultants#!/media/set/?se
t=a.555753287791955.1073741825.190372104330077&type=3> &type=3

http://www.ecodesignarchitects.co.za/ecodesign-projects/residential-projects
/category/46-house-morris.html

http://www.ecodesignarchitects.co.za/ecodesign-projects/community-involvemen
t/category/20-wolvekloof-training-workshop.html

http://www.ecodesignarchitects.co.za/ecodesign-projects/public-buildings/cat
egory/34-nieuwoudtville.html

 

In 3rd world / developing nations – where I work – labour is cheap and i
believe it is important to create job opportunities for people, so I prefer
using labour based methods wherever possible. I imagine that spraying it on
with machinery is also highly effective, but is not something I advocate for
this part of the world. Here we need to create job opportunities for people
and desist enslaving more and more of our ways to ones that are dependent on
machines and develop simple ways of doing things. We still have a hand
plastering tradition in this country and gunnite / or sprayed plasters are
not used in our building trade except, in the swimming pool industry for
making ferro-cement pools. So here we need to work with hand plastering
methods and what I like about the “pre-coating” method is that it combines
speed with strength in a labour based low carbon dependant method. 

 

But yes I need to change my terminology from using the word dipping to using
the word pre-coating or something similar because the word dipping is really
quite mis-leading.  I find as humans sometimes we can get so wrapped up in
our own jargon / words that we sometimes forget that we may not be
communicating what we intend and wonder why things get misinterpreted.
Thanks for picking on that Andre. 

 

Kind regards,

Andy

 

Logo-and-Address

 

From: GSBN-bounces at sustainablesources.com
[mailto:GSBN-bounces at sustainablesources.com] On Behalf Of
forum at lamaisonenpaille.com
Sent: 06 April 2013 10:08 AM
To: GSBN at sustainablesources.com
Subject: Re: [GSBN] Wall Heights - Larger & Multi-storey Straw Bale
buildings

 

Hello everybody, 

......for instance I would think that if one had an earth plaster for
instance which was very well bonded into the straw (as with say a
pre-dipping method where one has up to 80mm of earth fused with the outer
layer of straw)  

I just wanted to comment on the dipping method for creating a -supposed-
superior bond.

Chris Magwood (correct me if I'm wrong) who has dipped with  French Dip-Tom
Rijven has tested different types of bonding plaster to bales and the
outcome (not surprisingly) was that dipped bales do NOT hold their plaster
any better then other methods. 

I have also dipped with Tom and opening up them bales afterwards showed no
penetration in dense bales.

IMHO, in order to create the best bond one can, one has to drive the plaster
into the bales as hard as one can. 
Letting a bale sit in a few inches of slip does not 'wick' the plaster in a
bale. And if it does go into the bale, I worry about the density of that
bale.

Have a nice weekend,
André
France

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