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GSBN: Digest for 2/7/05



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-> Ooops! repost request
     by billc_lists@...
-> Re: Exterior cladding question
     by Derek Roff derek@...
-> Re: GSBN:Exterior cladding question
     by Rene Dalmeijer rene.dalmeijer@...
-> Re: GSBN:Exterior cladding question
     by "Lorenzo Robles" lorobles55@...


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Date: 7 Feb 2005 13:44:43 -0600
From: billc_lists@...
Subject: Ooops! repost request

Hi folks,

While making some configuration changes to our mail systems last
night in order to battle spam, I managed to leave GSBN (and a couple
of other addresses) out.

If you sent any GSBN mail since last night and haven't seen it come
through yet, please resend.

Apologies for the inconvenience.

- --
Bill Christensen
<<a  target="_blank" href="http://sustainablesources.com/contact/";>http://sustainablesources.com/contact/</a>>

Green Building Professionals Directory: <<a  target="_blank" href="http://directory.sustainablesources.com";>http://directory.sustainablesources.com</a>>
Sustainable Building Calendar: <<a  target="_blank" href="http://SustainableSources.com/calendar/";>http://SustainableSources.com/calendar/</a>>
Green Real Estate: <<a  target="_blank" href="http://SustainableSources.com/realestate/";>http://SustainableSources.com/realestate/</a>>
Straw Bale Registry: <<a  target="_blank" href="http://sbregistry.sustainablesources.com/";>http://sbregistry.sustainablesources.com/</a>>
Books/videos/software: <<a  target="_blank" href="http://bookstore.sustainablesources.com/";>http://bookstore.sustainablesources.com/</a>>


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Date: 7 Feb 2005 14:12:13 -0600
From: Derek Roff derek@...
Subject: Re: Exterior cladding question

- --On Sunday, February 6, 2005 10:38 PM -0500 Chris Magwood
cmagwood@... wrote:

> The issue is permeability. Obviously, the compressed earth bricks are
> going to be less permeable than the plaster, based on the thickness (10
> inches) and the density.

I think the issue is a bit bigger than permeability.  You will have a
materials change interface outside your insulation, between the bales and
the block.  This means that almost every day, during part of the day, the
compressed block will be substantially cooler than the interior of the
building.  This will be worst in the winter.  While the bales will have a
temperature gradient from inside to outside, the bale to block interface
will be a condensation site, much of the time.

I think this creates a potential site for serious moisture problems.
Substantial liquid water from condensation will be more destructive than
the same amount of moisture would be, if it stayed in vapor phase.  And the
moisture in vapor phase might still be a problem, given the relatively low
permeability of ten inches of compressed earth block.

Are there other options?  One that comes to mind, is to build your brick or
compressed block appearance walls at the outside of an unheated wrap-around
porch space.  The bale walls could be set inside by eight or so feet.  This
space could be a comfortable display space during part of the year, and an
airlock-like wind/weather buffer during the winter.

I don't know if this will work with the site and the plans, but my point is
to look for new options for meeting the appearance desires, without having
the bales close to the bricks or blocks.

Derek

Derek Roff
Language Learning Center
Ortega Hall 129, MSC03-2100
University of New Mexico
Albuquerque, NM 87131-0001
505/277-7368, fax 505/277-3885
Internet: derek@...



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Date: 7 Feb 2005 17:11:32 -0600
From: Rene Dalmeijer rene.dalmeijer@...
Subject: Re: GSBN:Exterior cladding question

Chris,

This is my humble opinion.

I am almost certain the mud bricks will have too little permeability to
be completely safe. It might work because these bricks can buffer quite
a bit moisture and let it out during the drier season but I would not
count on it at least not for such a prominent building. I don't think
an experiment is right in such a location. Stick to what you already
have quite extensive experience with, plaster carefully and maybe even
score the surface to replicate the effect of stone buildings. I am sure
you will be able to create a pleasing effect without the risk of an
experiment.


On Feb 7, 2005, at 04:38, Chris Magwood wrote:

> Hello all,
>
> I'm in the midst of designing a building for the Town of Haliburton,
> Ontario, which will provide a new space for a charitable group in which
> they will run their food bank and thrift store operations. It's a great
> project, as the building has an honourable end use and will be located
> right in the centre of the town, next to the art gallery and a park.
> They are also keen to make it as sustainable as possible.
>
> One of the requests of the town council is that the building be
> designed to "fit in" with the existing local architecture. The art
> gallery used to be a train station, so it's a nice building to echo.
> But part of fitting in in this part of Ontario is a having a brick
> finish. I've done some brick and stone facades in front of bale walls
> before, but I'd rather not do them again.
>
> One option I'm looking at is the use of compressed earth bricks. I had
> a chance to see them being produced and even to lay some up during the
> ISBBC in Denmark this summer. A local builder has recently purchased
> one of these machines, and I've already decided to use them in the
> floor.
>
> I don't have any doubt that the earth bricks can be used as an exterior
> cladding. What I'm wondering is this: If I lay up the bricks as an
> exterior load-bearing wall, can I stack the bales directly against this
> wall? I'm a convert of the Tom Rijven school of dipping bales in clay
> slip, so I would dip the back side of the bale and press it against the
> earth bricks, then give the interior the usual coat of earth plaster.
>
> The issue is permeability. Obviously, the compressed earth bricks are
> going to be less permeable than the plaster, based on the thickness (10
> inches) and the density. But do you think this will be problematic?
> Will the earth bricks be capable of taking up migrating moisture and
> letting it go to the outside at a reasonable rate? I'm pretty good at
> detailing a bale building by now, so there won't be any gross air
> leakage, just what makes it through the plaster. I would treat the
> earth bricks with silicate paint, which shouldn't hamper the
> transpiring of moisture much.
>
> I don't really want to do a typical brick veneer with an air space
> between the bales and the bricks. Having done it before, I know that
> it's nigh on impossible to maintain an even air space with a bale wall
> unless you get into using wooden spacers or other material and time
> intensive fixes. It seems to me that a patchwork of air gaps surrounded
> by bales contacting the bricks would be worse than no air space at all.
> So my option is use the bricks, or don't use any cladding and just make
> the exterior plaster nice and square.
>
> Let me know what you think...
>
> Chris
>
> ----

>
>
Rene



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

Date: 7 Feb 2005 18:53:35 -0600
From: "Lorenzo Robles" lorobles55@...
Subject: Re: GSBN:Exterior cladding question

Hello Chris;



   What I can tell, from my own observation and experience, both in France
and in Morocco,

is that earth, once dried, has an enormous capacity to deal Slowly (but
surely) with moisture in buildings.

   Even with very thick walls (in Southern Morocco, good old Kasbah walls
are often 80 cm thick or more (that's about 30 inches at least) never heard
of moisture problems.   Well, you could say it may be because Morocco is
like Arizona: very  hot, very dry,  So  moisture never matters...

   But in France there are quiet a lot of old farms, houses, and even
Chateaux, built with mud bricks or rammed earth or cob.

   Not only in the south; in wet and cold areas too; in winter, it was wet
outside, all the people breathing inside, plus the cattle in old times, and
it just did it; these houses lasted hundreds of years and many still exist



   When I was building in Morocco, often with mud bricks, I was amazed how
fast mud gets dry.

  When a brick came out of its mould, it looked like thick yogurt almost,
you could get easily a finger right through, effortless. After a day, you
could lift the brick, it wouldn't break easily.    After 3 days you could
use it  (even though I had them standing a whole week for total safety).
Each piece was 13 X 6  X 4 inches.

  We could say, definitely, that earth is always "in a hurry" to loose any
enclosed water . It is absolute breathability.

  Earth is the best friend of straw because it will drive away all presence
of moisture.



In your Halliburton project, I am 100% confident you can   proceed as you
describe, no  fear: connect fully the bales to the brick wall.

  There wont be condensation , because mud , especially if mixed with some
chopped straw (for the contact mud mortar) is not cold and shiny, but warm
and micro porous,  doesn't condensate the tiny water drops of  vapour. It
allows it inside via its porous surface.

   You could probably get a  condensing. point if the clay carried a lot of
sand (witch may get colder, and has a "locked" surface, non absorbing.

   Or by polishing, pressing in, the clay surface, like when building an
earth floor: then water is stopped at the surface because everything was
done to stop it.

  This doesn't happen with mud bricks, or cob :  compression is not
sufficient.

   All mud aren't identical: depending on microscopical structure diversity,
some being more breathable than others.

   Testing their qualities before choosing an earth for bricks or cob is
preferable.



   Does Ontario have earthquakes?  Because  an other advantage of full
contact between bales and the wall is extra solidity

added: the bales will reinforce structurally the wall they stick to.



Lorenzo Robl#232#s

- ----- Original Message -----
From: "Chris Magwood" cmagwood@...
To: "GSBN" GSBN@...
Sent: Monday, February 07, 2005 4:38 AM
Subject: GSBN:Exterior cladding question


> Hello all,
>
> I'm in the midst of designing a building for the Town of Haliburton,
> Ontario, which will provide a new space for a charitable group in which
> they will run their food bank and thrift store operations. It's a great
> project, as the building has an honourable end use and will be located
> right in the centre of the town, next to the art gallery and a park.
> They are also keen to make it as sustainable as possible.
>
> One of the requests of the town council is that the building be
> designed to "fit in" with the existing local architecture. The art
> gallery used to be a train station, so it's a nice building to echo.
> But part of fitting in in this part of Ontario is a having a brick
> finish. I've done some brick and stone facades in front of bale walls
> before, but I'd rather not do them again.
>
> One option I'm looking at is the use of compressed earth bricks. I had
> a chance to see them being produced and even to lay some up during the
> ISBBC in Denmark this summer. A local builder has recently purchased
> one of these machines, and I've already decided to use them in the
> floor.
>
> I don't have any doubt that the earth bricks can be used as an exterior
> cladding. What I'm wondering is this: If I lay up the bricks as an
> exterior load-bearing wall, can I stack the bales directly against this
> wall? I'm a convert of the Tom Rijven school of dipping bales in clay
> slip, so I would dip the back side of the bale and press it against the
> earth bricks, then give the interior the usual coat of earth plaster.
>
> The issue is permeability. Obviously, the compressed earth bricks are
> going to be less permeable than the plaster, based on the thickness (10
> inches) and the density. But do you think this will be problematic?
> Will the earth bricks be capable of taking up migrating moisture and
> letting it go to the outside at a reasonable rate? I'm pretty good at
> detailing a bale building by now, so there won't be any gross air
> leakage, just what makes it through the plaster. I would treat the
> earth bricks with silicate paint, which shouldn't hamper the
> transpiring of moisture much.
>
> I don't really want to do a typical brick veneer with an air space
> between the bales and the bricks. Having done it before, I know that
> it's nigh on impossible to maintain an even air space with a bale wall
> unless you get into using wooden spacers or other material and time
> intensive fixes. It seems to me that a patchwork of air gaps surrounded
> by bales contacting the bricks would be worse than no air space at all.
> So my option is use the bricks, or don't use any cladding and just make
> the exterior plaster nice and square.
>
> Let me know what you think...
>
> Chris
>
> ----
> GSBN is an invitation-only forum of key individuals and representatives of
> regional straw construction organizations. The costs of operating this
> list are underwritten by The Last Straw Journal in exchange for use of the
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>
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>
>


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