Wednesday, July 15, 1998 12:23:03 PM
GSBN Item
From: Huff and Puff Constructions,huffnpuff@...,Internet (greenbuilder)
Subject: Re: Soil Cement- my 2
To: strawbale@...,Internet
Cc: GSBN
John Glassford here

I would like to add my comments to Bill's post re wall-coatings. I too
have an aversion to PC (portland cement) in wall finishes, however it is
early days here and our building authorities understand PC. It is hard
enough getting SB (straw bale) approved with PC render and would be even
harder with clay/lime finishes. Firstly load bearing walls require PC
for strength and secondly we do not have any data on alternative renders
in combination with load bearing walls to satisfy Councils as to their
strength. I want to use clay/earth/lime renders and floors as soon as
possible. My questions to the list:

Are there any people out there who have built load bearing walls
with clay/lime renders or earthen that have obtained building
approvals? If so how strong was the clay/lime render?

Is there anyone doing research on alternative renders in
combination with load bearing walls? If not, are there any
potenial PHd students out there who want to?

Has any survey been conducted on existing SB houses that have
been up for some time from the point of view of moisture
penetration? Would it be possible to do such a survey and if so
how could it be funded? For my part I would help from our end.
Between New Zealand and Australia we would have 30-40 houses up
now.

We have a SB wall that we built 18 months ago, it was built in a
workshop`situation and as a consequence was not finished. This has
meant that we have a wall in three phases of construction. I use the
wall to demonstarte to potential clients. However the wall is now
deterioting badly in the areas that did not have the brown or finish
coats. I have also sampled straw from the finished areas and even the
straw in these areas are high in moisture and starting to go mouldy on
the edges. We are experiencing a very wet winter. Our rainfall is
normally 48" per annum, we had 8" in one day last month. I will be
pulling the wall down soon, (we are leaving Kangaroo Valley and moving
out West) and I will do an analysis on the wall and let you know what
has happened.

My genuine concern is that we do not know enough yet about PC, moisture
and SB and more observations and research are needed. In the mean time
I will carry on building and pursuade my clients to have large eaves and
preferably wide verandahs. The people of NE Poland who have had SB
houses up for some 35 years built theirs with verandahs all round and
down to the ground.

Regarding cracking in this wall we did not get any at render time
however it started to crack 6 months ago and has developed three large
vertical cracks indicating to me that the render in the walls are now
taking all the weight.

In the complex of buildings at Moss Vale we painted all the walls with a
cement based acryclic paint. (See my web page on current project).
This paint goes by the trade name Murrobond and is claimed to be
breathable as well as waterproof. It had better be, as there are no
eaves on these buildings.

Regards John Glassford. Wet, Worried and Wondering about Water.
http://strawbale.archinet.com.au

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Date: Wed, 15 Jul 1998 10:10:47 +1100
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Subject: Re: Soil Cement- my 2
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