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GSBN:Re: fire test -- your opinions?
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
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
I can't wait to find out what the final decision will be! Over to you, boys.
WARNING: Strawbale building can seriously transform your life!
Strawbale Building, Training and Consultancy
Tel/fax: 00 44 (0)1706 814696