[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: GSBN:Re: fire test -- your opinions?



I have to say that I love having this forum and that it has never
worked any better than it's working right now!

So, here are a few questions that perhaps some of you with more
experience with lime and perhaps with earth might be able to answer...

Given that we are not going to have 12 weeks to cure the finish on
these panels, is there a likely way that we can do a lime render and
have it stand up to the test, including the hose stream test since if
it fails that it fails the test? And do we know anything about how less
than adequately cured lime render will respond to a couple of hours of
intense heat and then the thermal shock and erosion of the hose stream
test?

Your questions, Barbara, about whether we know enough here to be using
lime plaster well is one that has been on my mind a lot over the last
few years as I listen to people who are really struggling to make these
things work and find themselves redoing jobs and trying to understand
what went wrong. The risk for the use of lime in such a test, if we are
having a hard time getting it right on ordinary walls doesn't reassure
me that it is a good choice here. But maybe I just don't know enough
about it and there are people here who do really know.

And second, I keep thinking about how much clay one would need to have
in the mix to get anything like at least minimal fired-clay
characteristics in earthen plaster?

It would be so much easier to make these decisions if we knew that we
had a back up plan for failure - a way that we could then take what
we've learned and do it again. I've just been at this long enough to
place a very high value on the fact that we now, finally have the
funding to carry out tests that we need, I believe, as much for
convincing the insurance folks and the building officials that this is
a safe and viable building system. We don't need to convince ourselves
of it although I am certain that we still have a great deal to learn...

I suppose some of us have been through the wringer enough times that we
are a bit cautious. One day soon, it's my hope that it is the newly
wide awake insurance and reinsurance sector that funds this sort of
research as they strive to address and survive climate change and peak
oil risks...I'm working on that in a variety of ways but who knows what
will unfold there.

-----Original Message-----
From: Strawbalefutures info@...
To: GSBN@...
Sent: Wed, 26 Apr 2006 23:48:23 +0100
Subject: GSBN:Re: fire test -- your opinions?

 Hi All
Just catching up with this very 'USA' debate. First, though, Fantastic
you've got the funding for it and are putting so much thought and energy
into getting it right. From my European perspective, I am still a bit
bemused at your insistence on using cement in any shape or form in
buildings
since it is has no positive environmental credentials, is rigid instead
of
flexible, waterproofing instead of weatherproofing, and non-permeable to
vapour instead of permeable. It is a major contributor to the green
house
gas effect and global warming, uses up 50% of the UK annual electricity
production to manufacture, does not have a cycle of use that returns it
back
to a harmless natural form and by all accounts also blocks aura's (for
the
spiritual amongst us!). Finally it is a thoroughly modern, (invented in
1824
and used widely from 1914ish) new and untested material in the sense of
withstanding the test of time compared to lime that has at least 12,000
years of continuous successful use and clay which has far far longer,
probably as old as the human race itself. As well as only specifying
natural
plasters and renders of either lime or clay we have also pioneered
low-impact foundations that use no cement, and solid floors made with
either
lime or clay. All these designs have already been passed by UK Building
Regulations.
I think you need to beware of limiting your vision to testing what you
know
will pass the test (i.e. lime/cement render, which has been thoroughly
tested already) instead of making sure you all have the opportunity to
catch
up with Europe and enshrine the use of cement free renders and plasters
in
your building codes - but you have to believe that our centuries of
tradition are valid, of course.
There is one other point to consider, though, which is that you also
need to
understand the way lime works to use it effectively, because it is not
like
cement, and this in itself may be your own limiting factor - do you know
enough about it to use and specify it?
My vote, in case you hadn't realised by now, would be for a feebly
hydraulic
lime render on one wall and the best clay plaster you have on the other.
Both will pass the 2 hour test I'm sure but the clay may or may not
pass the
hose test, would be interesting to find out. And to use bales flat for
one
and on edge for the other because hey, why not. Even though we pretty
much
know what will happen.
As Chug said, we were involved in a fire test with the Building Research
Establishment that can't be given a BS stamp but never-the-less showed
that
lime rendered strawbale walls with straw laid flat will withstand fire
for
more than 2 hours - the walls failed because of the design of the jig
and
would probably have withstood fire for longer in a real situation. We
used
feebly hydraulic lime, applied 12 weeks before the test, to both sides
of
the wall.
I can't wait to find out what the final decision will be! Over to you,
boys.
Barbara Jones


WARNING: Strawbale building can seriously transform your life!

Amazon Nails
Strawbale Building, Training and Consultancy
Hollinroyd Farm
Todmorden
OL14 8RJ

Tel/fax: 00 44 (0)1706 814696
email: info@...
web: www.strawbalefutures.org.uk



----
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 GSBN
as an
advisory board and technical editing arm.

For instructions on joining, leaving, or otherwise using the GSBN list,
send
email to GSBN@...HELP in the SUBJECT line.
----