[Greenbuilding] Sawdust + clay (was Re: straw clay)

[JOHN SALMEN]

Whatever happened to the bio-block??

Problem with sawdust mixes in any thickness is drying. Takes forever and is
often a crumbly mess if the sawdust content is too high but then not very
insulating if not. Works for a render. Chips are great but are actually
getting harder to get.

A lot of sawdust here is now ending up in fuel log or fuel chip production.
Larger shops are actually installing equipt to deal with the dust at the
source.  


JOHN SALMEN ENVIRONMENTAL DESIGN
4465 UPHILL RD,. DUNCAN, B.C.  CANADA, V9L 6M7
PH 250 748 7672 FAX 250 748 7612 CELL 250 246 8541
terrain at shaw.ca


-----Original Message-----
From: greenbuilding-bounces at lists.bioenergylists.org
[mailto:greenbuilding-bounces at lists.bioenergylists.org] On Behalf Of RT
Sent: October 15, 2010 11:23 AM
To: greenbuilding at lists.bioenergylists.org
Subject: Re: [Greenbuilding] Sawdust + clay (was Re: straw clay)

On Fri, 15 Oct 2010 12:54:12 -0400, Michael O'Brien <obrien at hevanet.com>  
wrote:


> We are building a small studio using cedar wood chips coated with a clay  
> slip to fill 8" Larson truss walls.

> I don't know the conductive heat loss of this setup, but I would guess  
> it is similar to solid wood at about R-1 per inch, maybe a little better  
> because of the air spaces.

I'll bet the thermal resistance would be a lot better if the clay were  
omitted. [insert EVIL WINKING SMILEY]

Some years ago, back in early-mid-90's of the previous millennium, a group  
across the Ottawa River in Gatineau Quebec calling themselves  
"Internatural" had planned to develop a building block called "Bioblock",  
made of a soil-cement-bonded matrix of waste wood fibres (ie ground-up  
non-returnable wooden shipping pallets, a disposal problem in most urban  
centres, or shredded forest canopy waste) with some "miscellaneous"  
shredded waste that could not be handled by Blue Box recyclijng programs.)

They proceeded to a "Proof of Concept" study under CMHC's "Housing  
Technology Incentives Program" (HTIP) and discovered part way into the  
study that they could eliminate the soil cement component (ie  
substantially reducing the BCJohn Labour Intensiveness Quotient (BLIQ))  
... and simply dump the wood chips into rectangular fibre mesh sacks,  
compressing the "block" with a hand-operated press to create a wood chip  
"bale" that could be stacked into wall panels ... and then plastered just  
like straw bales with pretty much the same thermal properties.

Unfortunately, for those with an aversion to hard work, plastering by hand  
is pretty high on the scale of "labour intensiveness".
But of course, that can be made a little easier with plaster spraying  
gizmos or fabricating the walls as pre-cast, tilt-up panels.

And of course, the above wouldn't work very well for sawdust. Pretty much  
need the soil cement.

Sawdust-soil-cement blocks look a lot like the old-fashioned "Trex" lumber  
or perhaps what some might describe as big chunks of dried horse manure.


-- 
=== * ===
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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