[GSBN] Emerald update (GSBN Digest, Vol 33, Issue 17)

[RT]

On Thu, 27 Jan 2011 13:00:03 -0500, <gsbn-request at greenbuilder.com> wrote:>
> Message: 1
> on Thu, 27 Jan 2011 09:21:17 +1000
> "Chris Newton" wrote:
> Re: Fw: Emerald update

>  Currently we plan to replace [all of the flood-damaged bales] with  
> engineered high density expanded polystyrene foam blocks.
>
> Of course we are really interested in any other greener product out  
> there that will meet the needs, we have a few months up our sleeve to  
> explore and experiment.
>
> I guess we are now looking at replacing 2 layers of bales around the  
> whole building. I hear conversations between Lance and Col about  
> supporting the upper bales in various ways while the damaged bales are  
> removed, and having to put a new capillary layer on top of the expanding  
> foam.
[snip]

(for full text of message/thread, see
       http://greenbuilder.com/pipermail/gsbn/2011q1/001252.html )

Sitting here high/dry/cool in MooseLand, over 15,000 kms away and on the  
other side of the planet from Queensland allows me the luxury of being  
uninformed about the actual circumstances at the site and hence, able to  
say, without any qualms and with great mock indignation:

     "Whu- Whu-What? REPLACE STRAW BALES WITH EXPANDED POLYSTYRENE BLOCKS  
???

On the subject of supporting upper portions of the walls in order to  
replace the bottom 2 courses of bales:

In the past when punching out six metre-wide (20 ft in Murrican) openings  
through the first storey of two-storey high, triple-wythe, loadbearing  
brick-walled houses, I have cut out the mortar line beneath the header  
course from each side of the wall (combination of angle grinder + hammer &  
chisel work), one side at a time so that the uncut side still has full  
bearing and is still able to carry the portion of wall above ... and  
inserted a flange of a steel angle lintel (engineered for the load) into  
the partially-cut-out mortar joint, with the ends of the lintel extending  
past the ends of the proposed opening to bear on the portions of wall that  
will remain.

Then with the steel lintel supporting one half of the breadth of the  
header course, cut out the mortar line from the other side of the wall and  
insert another steel lintel.

With the steel lintels fully supporting the header course and the portion  
of the loadbearing masonry wall above, the masonry below the lintels can  
be safely removed.

This process could easily be adapted/used to remove entire bottom courses  
of a plastered bale wall, the steel lintels being removed for re-use or  
sale, after the bale replacements have been inserted.

re: Bale Replacements

Quite frankly, (and Shirley too) I think that EPS blocks would be overkill  
(from a thermal insulation perspective), overly expensive (both from cost  
and Green perspectives) and not necessarily a good choice (from an ant and  
termite resistance perspective).

WRT to the latter, I've seen EPS in ground contact situations reduced to  
hollow shells honey-combed with ant tunnels in as little as one  
fall/winter. In termite country (Oz ?) I imagine the destruction process  
would be accelerated with awesome ferocity.

Assuming that the wall was originally made with 2 or 3-string bales, a 150  
mm thickness of EPS (or better, a non-moisture-susceptible mineral wool  
insulation like Roxul ... same R-value as EPS) would provide the  
equivalent-to bales insulation value.

I think that I'd look at making the lower course bales wall replacement as  
an insulated core sandwich wall, with the loadbearing "skins" being 100 mm  
(4 inch) thick concrete masonry units (CMU) or similar.

True, the CMUs would be relatively high in embodied energy but they can be  
easily deconstructed at the end of the building's useful life and re-used  
any number of times, amortising that high EE cost over a century or more,  
effectively reducing that EE cost to a minimal amount.

If thermal resistance isn't a major concern and if a "natural" insulation  
like mussel shells are locally available , all the better.

-- 
=== * ===
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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