[Greenbuilding] Greenbuilding Digest, Vol 20, Issue 32

[MKL]

I have been thinking about the question of building
walls  for some time and have been so moved by straw
bale walls I have actually built a preliminary "guest
house" cabin over the past few years to examine the
issues prior to building the main straw bale house.
This small building was hand plastered in almost daub
fashion with lime putty/sand only plaster on the
exterior and "cobbed" (earth sand straw) on the inside
to air seal the bales. 

In doing this on a weekend / off time basis it has
taken me quite a long time and I now question whether
this process should be undertaken by an individual
working alone especially if primary human shelter is
the objective. In my case this was fortunately not the
case. 

If there are many free inexpensive hands available
this approach might be valid in a rural or agrarian
based region and possibly there are other exceptions
to the rule that hand based craft is expensive and
that machine based processes are expensive thus
forcing a choice between long term hand work with or
without professional help or the fast but pricy
specialist coating crews.

The decision for me regarding which materials to use
where I am building comes to cost to me of the
materials and of course their acceptability in terms
of ability to provide the requisite energy savings and
protection from the elements without the necessity of
using wood or other processed new blend of materials.

Without explanation I would suggest the following and
invite comment on its merits.

Walls would consist of structural members (local
availibity of recycled material wooden posts etc
considered) to hold up the roof with sealed seamless
(taped) roxul batts in a sort of membrane  "cocoon"
(no other word I dont think) surrounding this
skeleton. The structural  members if 2x's could in the
cold side have loose cellulose packets as well stapled
in between the posts (easy to do I am guessing) The
point is apart from the posts holding up the roof
there would be nothing solid "in" the walls. (I have
left out details like wall board and vapour barrier at
this time) 

The walls would on the "outside" have a surface
perhaps wire or wattle reinforced which could take a
plaster/stucco "shell" coating similar to a strawbale
coating (but likely not needing to be as thick) but
still allowing a non industrial looking crafted finish
.The argument made by advocates of the load bearing
straw bale method is that the outer skin is what
supports the roof. This would not be necessary in this
case but it might demonstrate that a plaster outside
wall is adequate as elemental protection. 

New materials old method. 

Any one care to comment? Criticism welcome.

Michael Lough










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