Date: Wed, 19 Mar 1997 09:48:35 -0500 (EST)
From: fibre@freenet.carleton.ca (Linda Chapman)
Subject: sill plates, etc.
a few days ago some SLEEPY guy said:
- -----snip----
This tells me that anchorage for both the interior and
exterior sill plates should be designed to resist uplift
(something concrete nails aren't good at doing) if racking
is to be kept to a minimum. Either that, or it's late and
I've totally missed the point. (Entirely possible)
- ---reply---
Was it the St. Patrick's day green beer? Or did you never
get a copy of my structural report? I was sure you had!
The straw bale wall sample that we tested did not behave
like a rigid parallelogram as beautifully drawn in your
posting. When subjected to ENORMOUS horizontal
loading (7X horizontal hurricane winds) it behaved like a
beam sagging in the middle and began to creep (move
sideways). This odd sandwich panel handles racking
extraordinarily well. Bob Platts says this is because it is so
damn wide. He says its like trying to push over someone
with their feet spread 3 feet apart vs. someone standing
with their feet together. Try it on a friend, see how much
CREEP you can get out of them! This stessed skin panel is
odd indeed because it is rigid (the skins) yet elastic when it
wants to be because of its core, one of the reasons why I
suspect it will be great it seismic tests. I'm still trying to
understand it myself.
It has been a VERY long time since structures class
in university and they never explained stressed skin
panels to us anyway, so I rely on the analysis from an
engineer who spent many years of his life doing so.
My understanding of wind uplift and anchor bolts, I'm
SURE you will correct me if I'm wrong, is UP lift (re
tornadoes & hurricanes ala The Wizard of Oz), not
sideways force. Those heavy duty bolts anchor bolts and
nuts keep the wall and roof from flying UP to OZ. Well,
okay not the roof, you need good truss connectors for that,
which we have when we use the wire mesh itself
wrapped around and nailed to the truss as well as
connected to the sill plate which has really a very
minimal job to do, so 2" X 3"'s are indeed quite adequate
and have been used on real building that are now
standing.
Frank Servas suggested 2" X 3" s were a bit 3 little piggish:
- -----snip-----
Don't Know Why Folks Insist on Trying to Cut Corners
and Build Straw Bale
Houses Like the Three Little Pigs Did, Weak and
Unreliable. There are proven
methods which if used to build will result in a straw bale
house that will
last more than 100 yrs. It seems to me if you are
determined to build any
house you ought to do it right.
- -----snip------
The reason we are interested in using minimal sizes of
lumber is the very same reason that we are using straw
bales in the first place. To minimize the use of our ever
dwindling resource base, not very sustainably managed at
the moment, and provide good quality well insulated
housing at the same time.
I personally get quite disappointed with people who claim
to be environmentalists and then go framing a house
with huge OVERSIZED timbers and think they should be
congratulated for how ecosensitive they are. Geez! If we
can get the job done, (and I am betting my liability
insurance that prestressed Nebraska does last 100 years)
with minimal resources then we are doing everyone a
favour, not just cutting corners. (Aside from the fact that I
ain't seen a square corner on a straw bale house yet,
what's wrong with rounded corners?)
I think I need some green beer now! (Full Moon's
A Coming)
P.S. Norbert Senf has generously offered to put the
executive summary of the Fibrehouse prestressed
Nebraska testing report up on his web page. If you want
the full 35 page report with photos I would URGE you to
contact the CMHC to get a copy. They only way that they
will know how many people want them to pursue
research in this field is if they are swamped with requests.
GO 'AN SWAMP 'EM !
Their web site is: <www.cmhc- schl.gc.ca> and the number
to call to request a copy is once again (613)748-2367
Bye, the boss says I have to go back to work now,
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Linda Chapman Architect & Fibrehouse Limited
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Architects and engineers developing and improving
cellulose fibre based housing for people and the planet.
-- -------------------------------------------------------- Norbert Senf email: mheat@mha-net.org Masonry Stove Builders mheat@hookup.net RR 5, Shawville website: http://mha-net.org/msb Quebec J0X 2Y0 fax: 819.647.6082 voice: 819.647.5092 __________________________________________________________________ This greenbuilding dialogue is sponsored by Oikos (www.oikos.com) and Environmental Building News (www.ebuild.com). For instructions send e-mail to greenbuilding-request@crest.org. __________________________________________________________________