[GSBN] Wall Detail
Chris Magwood
chris at endeavourcentre.org
Wed May 23 21:41:42 UTC 2018
Hi Enga, and all who've waded into this fascinating discussion...
I'm really glad to be reading this thread, there's a lot of rich
questions and ideas here, and I think there's a lot of value in
exploring them. Perhaps this discussion can be a central part of an
upcoming Int'l Straw Bale gathering? I would love to have that kind of
extended opportunity to talk about these things.
But I have some thoughts that I'd like to get out there in this forum,
as a response to what I've read so far. This stuff is highly relevant to
my own practice lately, and I'm churning this stuff over in my mind a lot.
I found myself came in this field of endeavour as an owner-builder,
attracted by the apparent simplicity of bale building and all the other
great benefits that the renaissance pioneers (many of whom are on this
list!) brought to our attention. Having lived through making all the
obvious mistakes I made on my first house, I got really passionate about
figuring out how to do straw bale building better to save others from
the same mistakes. Thus began a couple of decades of building and
research...
Along the way, all kinds of things happened that have informed and
re-directed my efforts and energies. I'm going to point-form these to
keep this message shorter:
* *Issues with exterior plaster finishes* (in particular in a region
with little to no plaster experience, and a cold, wet climate and
citizens who are used to "maintenance-free" brick and vinyl
cladding). All of the really serious mistakes/failures with bale
buildings in this part of the world are due to issues with plaster
and plaster detailing. The cost of plaster finishes, whether in time
for owner/builders or cost for those doing the work professionally
is also highly relevant.
* *Issues with code.* Though we all know that load-bearing buildings
can and do work, and can even get permits (we've done over a dozen
here), in this part of the world it requires a structural engineer
to stick her/his neck out to approve this, and this costs owners a
lot of money and inevitably slows down permit times. There are also
many who simply can't find an engineer willing/able to do this for them.
* *Issues with building process/weather.* Ontario has a fairly short
building season, and one during which it can rain suddenly and
heavily on any given day. I often wonder if the number of poly tarps
sacrificed to keep bale walls dry in this part of the world
outweighs all the environmental plusses... I'm sure the answer is
no, but the amount of time spent tarping and untarping and the costs
in time and labour (and tarpage) is significant, and the reason that
many builders have pursued wood frame options to enable a roof to go
overhead before bales go in. We also can't plaster exteriors here
for 6 months of the year due to freezing conditions, which also
provides challenges aplenty.
* *Issues with energy efficiency.* Seems crazy to think, but our R-30
(ish) bale walls that were outstandingly energy efficient 20 years
ago are only just going to meet code minimum requirements here in
Canada within a couple of years. While a bale house was remarkably
energy efficient back then, we cold-climate inhabitants have learned
that if we want to be serious about reducing energy use, it takes
something more than a standard bale wall to get there. Net zero
homes are a good idea, and we can't do that very effectively with a
typical bale wall in our climate. There are also issues around
getting plastered bale buildings to be airtight enough to be truly
energy efficient... many crews have figured this out, but it's not
straightforward or simple.
* *Issues with "replicability."* Though many professional bale
builders have been able to develop systems and crews that allow them
to compete with conventional builders, it's clear by now that straw
bale building isn't going to take the mainstream building world by
storm. That in itself isn't a bad thing... bale building can fill an
important niche for both professionals and owner-builders. But for
those who want more buildings to have the improved ecological and
carbon footprint that comes naturally with bale buildings, it is
something of a conundrum... how do we achieve this if straw bales
are not the go-to solution for 99.9% of builders?
* *Carbon positive building.* One of the great things about bale
buildings is that they can store a whack of biogenic carbon, and can
even contribute to "carbon positive" buildings that store more
carbon than was emitted in making them. But not all bale buildings
do this... I've certainly seen bale buildings with enough concrete,
steel, lime, glass and other high emissions materials to negate the
carbon positivity of the bale walls. And for those concerned with
carbon positive building, there are other ways to make a carbon
positive building using other materials, and getting the same result
for the planet without using bales.
* /***It doesn't elude me that all of these issues are definitely
"first world problems!" The humble load-bearing bale building only
faces these issues when trying to compete with conventional options.
If we can change people's expectations of what a house should be,
this whole discussion would be a lot less central.../
My efforts in the field of prefab straw bale walls have all been
attempts to address these key issues and still use the material I love
so much. Prefab panels have allowed us to use the simplicity of
load-bearing design without facing the weather issues of plastering
outside, and also simplifying the plastering process so that it is much,
much less time consuming, fussy and skilled a task (because it's done
with the panel lying down flat... working with gravity!). Though it
hasn't been done very often, I see these kind of panels as highly
appropriate for owner builders who can build them in place on their
floor deck, and get them built, plastered and stood up in an easy,
manageable process, without needing lots of volunteers and being able to
adequately protect one or two panels from inclement weather quite
easily. Those who have done this have really benefited from the
technique, and are among the best owner-built homes I've ever seen, and
certainly the quickest, most affordable and painless (and, dare I say,
straightest). These plastered prefab walls help address code issues
(engineers seem happier if they know the plaster is a consistent
thickness, provides a straight load path, and won't delaminate between
coats), and offer a path to replicability that is much more direct than
with site built bales. The plaster finish is also straight enough that
mounting a rain screen cladding where appropriate is suddenly very
simple to do. For all of these reasons (and more), I've been really
happy with our plastered prefab panels, and continue to advocate for them.
However, the plastered panels are still limited in regards to their
energy efficiency, and the weight involved in making a pre-plastered
panel. Our most recent versions of "dry" panels are an attempt to
address all the above issues. By using insulated sheathing (wood fiber
board, which is as eco-friendly as a manufactured material can get and
more vapour permeable than earthen plaster) we up our energy efficiency
an important notch, and simplify air sealing details greatly. The labour
time for making panels is reduced significantly by eliminating the
plaster. And by adding the wood fiber board, we're storing more biogenic
carbon (even earthen plaster doesn't do that!).
Do our weird boxes stuffed with bales seem a long way off from my
beginnings as a bale builder? Yup indeed. But do they satisfy all of the
things that are important to me as a builder? Yup, they do. We can even
use clay plaster on the interior (haven't yet, but hope to soon!).
So that's one way (a little long-winded... sorry!) to keep using straw
bales and to address all the issues that have proven difficult for our
practice here in Ontario. We've experimented with others (like using
round bales as load-bearing columns, and using jumbo bales), but none
have had the simplicity and elegance of the "dry" panel.
I have certainly seen some potential solutions to straw bale problems
that are less than elegant, and at that point I do think it is
worthwhile asking if bales are the right material to be using. The
second I see anybody sawing, channeling or notching a bale, I
immediately wonder if this is an appropriate strategy. Why not
cellulose, another carbon-storing, recycled material that fills any void
perfectly? Why not hempcrete or straw/clay, also great at filling
framing cavities? Why not an exterior or interior frame of some kind
that won't interface with the bales? These are all important questions
to ask, and I think it's important that as practitioners we are open to
asking them and to arriving at an answer that is not straw bale.
I also think that we could collectively be thinking about new ways to
use the amazing straw resources we have. Can we shred straw and use it
like cellulose? Can we make stacking, interlocking bales? Can we make
bales that fit into standard framing dimensions without any on-site
carving? Can bales come with a base coat of plaster on the exterior and
interior so they can be dry-stacked, easily cut, and be weather
protected? These possibilities, and many more, exist for us to explore
(and there are those out there doing these things right now... let's
learn from them and support them!). After all, from a climate
perspective, we grow enough cereal grains every year that the straw
absorbs twice as much carbon as is emitted by all human transportation!
Turns out those little stalks are the most effective carbon capture and
storage machines ever invented. And we've all been doing the right thing
by bundling some if it up and putting it in houses for a long time. If
we can figure out ways to make it easy for people to do more of that -
even if it doesn't match our preconceived notions of a "straw bale house."
I think these are the issues/questions that underlie this discussion,
and I for one am keen to engage with others on figuring out solutions!
Whew, that was long-winded. Thanks to anybody who read this far!
Chris
On 2018-05-15 9:02 PM, Enga Lokey wrote:
>
> Hello you amazing builders/designers,
>
> At the risk of being chucked off the list for this question, I would
> like to play devil’s advocate here and ask what is being achieved by
> the use of strawbales in the methods discussed below and others that
> seem to be the direction that strawbale is moving (i.e. building wrap,
> 2x6 framing on 24in centers, external timber sheathing, etc). More
> specifically, it appears that the building methods are being adjusted
> toward a more standard construction to the point of wondering why the
> strawbale is even still used? There are other cellulose based products
> and other more natural or healthy insulation products on the market.
>
> We are all aware of the challenges of working with straw and thus
> there needs to be, in balance, a greater benefit in order to justify.
> Is that benefit still there when used in this way? Are we not using
> equal/more other materials in order to build with straw in these
> methods? Is it justified?
>
> And as the saying goes, "just because I am confused does not mean you
> are incorrect."
>
> Cheers,
> Enga
>
>
>
> enga at thelokeys.net <mailto:enga at thelokeys.net>
>
>
>
>
>
>> On 15 May 2018, at 9:21 pm, Rene Dalmeijer <rdalmeij at mac.com
>> <mailto:rdalmeij at mac.com>> wrote:
>>
>> Doug,
>>
>> I did a pre-fab 5 story SB build akin to the system used by David in
>> 2007. The difference being we used Fermacell with breathable
>> housewrap on the outside clad with open horizontal larch cladding.
>> This has been performing very well even though there have been some
>> leeks due to caulking problems in the window frames, No mushy bales.
>>
>> This has become my preferred Pre-fab SB method. Although I am now
>> involved in a pre-fab build without any earth plaster on the bales at
>> all, shudder! The bales will vertically stacked in prefab elements
>> with underlayment inner and outer skins with wooden vertical slab siding.
>>
>>
>> Rene Dalmeijer Proces Advies
>> Thomas Hoodstraat 2
>> 1086 WE Amsterdam
>>
>> 06 48955419
>>
>> KvK 34243755
>> BTW NL057444146B01
>> NL18ASNB0932817343
>> new email rdalmeij at mac.com <mailto:rdalmeij at mac.com>
>>
>> IBAN NL09INGB0004388720
>> BIC INGBNL2A
>>
>>> On May14, 2018, at 18:42, David Arkin, AIA <david at arkintilt.com
>>> <mailto:david at arkintilt.com>> wrote:
>>>
>>> Hello Doug:
>>>
>>> We completed a recent project using a ‘Hybrid Wall System’,
>>> employing typical 2x6 studs at 24” on center with plywood sheathing
>>> (note - plywood, not OSB - but in a non-seismic zone wood fiberboard
>>> or similar may suffice), and then installed the bales as insulation
>>> on-end between the studs, using clay plaster on the interior and a
>>> typical weather-barrier and cladding finish on the exterior.
>>> Attached is an illustration of the system, and here are links to
>>> the workshop and the finished building, a 34,000 mixed use office
>>> and warehouse in Eugene, Oregon.
>>>
>>> http://www.arkintilt.com/ata-helps-host-casba-hybrid-straw-bale-workshop-our-mahonia-building-eugene-oregon
>>>
>>>
>>> http://www.arkintilt.com/salvaged-materials-mahonia
>>>
>>> Also attached is a picture of the wall under construction. We used
>>> 3-string rye bales and held them tight to the plywood with 4” wide
>>> strips of 1/2” plywood, and 12” Timber-Hex screws into the studs
>>> (we'll use 14” screws next time - easier to find the studs, and a
>>> better connection).
>>>
>>> I also have the WUFI analysis our building efficiency consultant ran
>>> for various locations - they can run a weather file specific to
>>> Wilmington if you wish. LMK.
>>>
>>> This is not quite a ‘StrawCell’ as it doesn’t feature cellulose, but
>>> it could be appropriate to Delaware.
>>>
>>> Looks like a great project,
>>>
>>> David / ATA & CASBA
>>>
>>> <2017-0224 YW2 bale corner detail2.jpg>
>>> <IMG_9936.JPG>
>>>> On May 14, 2018, at 8:47 AM, Chris Magwood
>>>> <chris at endeavourcentre.org> wrote:
>>>>
>>>> Hi Doug,
>>>>
>>>> Here's a detail from our last straw-cell project. Hope it's helpful
>>>> to you. You can contact me off list if you want to discuss it.
>>>>
>>>> Cheers,
>>>>
>>>> Chris
>>>>
>>>> On 2018-05-14 11:03 AM, douglas nichols wrote:
>>>>> Hello All
>>>>>
>>>>> I'm consulting with a non-profit (http://www.yinnovations.org/) to
>>>>> build an affordable straw home for a low income family. Their
>>>>> current engineering was provided by someone unfamiliar with straw
>>>>> bale building and is coming up pretty short of being a low carbon,
>>>>> sustainable, or natural design. So we are moving to a straw cell
>>>>> design to help ease any engineering and building official concerns
>>>>> about the straw bale part. My question is-- does anyone have a
>>>>> good straw cell wall detail drawing they can point me to or donate
>>>>> to the effort?
>>>>>
>>>>> Y Innovations, Inc.
>>>>> www.yinnovations.org
>>>>> 2903 North Jefferson Street 2903 North Jefferson Street is a 4500
>>>>> square foot vacant lot in the city of Wilmington, where Y
>>>>> Innovations will be completing a 630 square foot naturally-built
>>>>> straw bale home in 2018.
>>>>> Thanks
>>>>>
>>>>> Doug Nichols
>>>>>
>>>>> Creating Energy Efficient Homes Since 1995
>>>>>
>>>>> Nichols Contracting LLC
>>>>> 821 S. 400 E.
>>>>> Moab, Utah 84532
>>>>> Cell #970.683.1517
>>>>> Lic. #9508518-5501
>>>>>
>>>>> Principal / Qualifying Builder
>>>>> Community Rebuilds Moab -- http://www.communityrebuilds.org/
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Gsbn mailing list
>>>>>
>>>>> Gsbn at sustainablesources.com
>>>>> http://sustainablesources.com/mailman/listinfo.cgi/gsbn
>>>>
>>>> --
>>>> Chris Magwood
>>>> Director, Endeavour Centre
>>>>
>>>> www.endeavourcentre.org
>>>> <Screen Shot 2018-05-14 at 11.29.45
>>>> AM.png>_______________________________________________
>>>> Gsbn mailing list
>>>> Gsbn at sustainablesources.com
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>>>
>>>
>>>
>>> * * * * *
>>> Arkin Tilt Architects
>>> Ecological Planning & Design
>>> 1101 8th St. #180, Berkeley, CA 94710
>>> 510/528-9830 ext. 2#
>>> www.arkintilt.com
>>>
>>> David Arkin, AIA, Architect
>>> LEED Accredited Professional
>>> CA #C22459/NV #5030
>>>
>>> Director, California Straw Building Association
>>> www.strawbuilding.org
>>> CASBA is a project of the Tides Center
>>>
>>> "There is no way to peace. Peace is the way."
>>> — A. J. Muste
>>>
>>>
>>>
>>>
>>>
>>>
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>>
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>
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--
Chris Magwood
Director, Endeavour Centre
www.endeavourcentre.org
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