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RE: GSBN:Exterior cladding question



In terms of risk relative to prominence I humbly agree with Rene's humble
opinion.  Are you sure you cant convince the owners?


Dr John Straube
Assistant Professor
Dept of Civil Engineering & School of Architecture
University of Waterloo
Waterloo, Ont. Canada
<a  target="_blank" href="http://www.civil.uwaterloo.ca/beg";>http://www.civil.uwaterloo.ca/beg</a>


-----Original Message-----
From: GSBN [<a  target="_blank" href="mailto:GSBN@...";>mailto:GSBN@...] On Behalf Of Rene Dalmeijer
Sent: Monday, February 07, 2005 5:44 PM
To: GSBN
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

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