[GSBN] Clay plaster language for IBC (GSBN Digest, Vol 10, Issue 18)

[martin hammer]

Rob (and all),

I'm in transit from Oaxaca, Mexico (great earthen building and stone
building traditions) via Santa Barbara (will see David Eisenberg, Laura
Bartels, Art Ludwig from this list at a sustainable policy retreat organized
by Art) and then back to Berkeley CA (no elaboration necessary).

The common criticism is that the International Building Code isn't
international.  It is international (including parts of it being used in the
middle east, and being considered if not already implemented in Mexico and
parts of South America.)  It was intended to be (thus the name).  And it is
expected to become more and more international, like it or not.  You can
argue this was all hubris, and was uninvited by the international community,
but the IBC and its format remain the practical reality we are working with
in the US, and soon maybe you in Canada and others elsewhere.

Yes, it has an American, industrialized building bias, but in some contexts
that¹s not a bad thing at all.  Yes, it has many shortcomings, and is not
particularly ³green².  That¹s why more and more people, like the GSBN¹s
David Eisenberg, have been working for years to change it, or add to it.
That¹s also what I, with help from many others, am trying to do now.

I didn¹t mean to imply that this clay plaster section should or would be
only prescriptive.  It will likely be a mix of prescriptive and performance
language.  Whatever works for the subject at hand.  Whatever works and is
acceptable to a majority of those who sit at the building code table.

The notion that all code language should be performance-based is frankly
nonsense.  Some things do not lend themselves to being defined by
performance, because they are not easily evaluated at plan check or easily
enforced in the field.  In many cases performance language is more
cumbersome than a simple prescription that pretty much guarantees
performance and doesn¹t tie anyone¹s hands.  No one is going to say ³straw
bales shall be dry enough so that they will not bio-degrade² (performance),
when you can say ³straw bales shall not exceed 20% moisture content²
(prescriptive).

Your suggestion ³to simply specify what the straw needs in terms of
protection from wetting, capacity for drainage/drying, fire resistances
etc.², is in many ways appealing, but is not simple.  Also, aspects like
fire resistance and structural capacity are tied very strictly to tested
assemblies, and thus they are prescriptive (but can sometimes be altered
with approved engineering analysis).

However, I agree with your intention, and performance language is my first
choice (because it describes the goal to achieve, but not how to achieve
it), and there is a fair amount of it in this proposed code as it stands.  I
just encourage being open to prescriptive language if and when it works
best.


Martin (I¹m trying to perform but I need a prescription) Hammer



On 1/17/12 4:34 PM, "RT" <archilogic at yahoo.ca> wrote:

> On Tue, 17 Jan 2012 16:02:00 -0500, <GSBN-request at sustainablesources.com>
> wrote:
> 
>> From: martin hammer <mfhammer at pacbell.net>
>> To: GSBN <GSBN at SustainableSources.com>
>> Subject: [GSBN] Clay plaster language for IBC
> 
>> 
>> I proposed a Strawbale Construction section for the International
>> Building Code (IBC) on January 3.
>> One area of this ?code? I feel is under-developed is the part on Clay
>> Plaster (and secondarily Soil-Cement).
> 
> Not being an Murrican, I don't know anything about the
> (not)"International" BC  but it seems overly cumbersome and not
> particularly effective in achieving what I hope is the intended purpose.
> 
> Rather than trying to come up with prescriptive standards for bale
> plasters it would seem to make more sense to specify performance criteria
> for the situation to which the plaster will be subjected.
> 
> ie loads and climate do not have one set of conditions when attacking
> brick veneer claddings, another for wood, another for cement plaster and
> another for earthen plasters.
> 
> Nor does straw have different requirements for protection when clad by
> each of the preceding.
> 
> It would seem to make more sense to simply specify what the straw needs in
> terms of protection from wetting, capacity for drainage/drying, fire
> resistances etc.
> 
> Then it would be up to the designers to provide the appropriate
> configurations to provide that protection.
> 
> What the IBC document might provide are some tables showing what
> characteristics various cladding materials can provide for specific
> compositions/configurations.
> === * ===
> Rob Tom
> Kanata, Ontario, Canada
> 
> < A r c h i L o g i c  at  Y a h o o  dot  c a  >
> (manually winnow the chaff from my edress if you hit "reply")
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