[GSBN] SB Overhangs (was Big News!)
Rikki Nitzkin
rikkinitzkin at earthlink.net
Wed Sep 1 11:52:28 UTC 2010
Hi all,
Maybe this code could include various Options since there are many
ways to solve the problem.
About protecting clay-plastered walls from wind-driven rain or un
protected gable roof walls, there is always the option of a ventilated
rain-screen. I have seen many different options made with wood in
Denmark, and on some of Tom Rijven's buildings in france. The rain -
screens can be simple, beautiful and permit clay plaster.
By the way, are you all aware of the Loadbearing Dome and Vault
building (with a Green Roof) Gernot Minke is working on in Slovakia?
It should be quite spectacular, and could make a nice article for TLS.
I am off to participate in the build next week. Check out fotos at: http://minke-strawbaledome.blogspot.com/
baling on...
Rikki
El 26/08/2010, a las 13:03, martin oehlmann escribió:
> Hello all,
>
> again compliments to all this great work which in essence should
> make things easier by systemized solutions. If I read Andys remarks
> on freedom of desgin we might be able to solve the paradox of
> securing people from design failures and at the same time stimulate
> ongoing experiments by a simple preamble for codes: ."this or better".
>
> This would be an opening to convince building inspectors for what's
> not be known yet, but definitly soon will be offered. Without
> flexibility there is just little innovation. And it is the "cemented
> aspect" of the building industry which spends a minimum for
> innovation in comparison to other sectors.
>
> Best wishes from a rainy Brittany,
>
> Martin Oehlmann
>
>
>
>
> ----- Original Message -----
> From: Andy Horn
> To: '(private, with public archives) Global Straw Building Network'
> Sent: Wednesday, August 25, 2010 10:36 PM
> Subject: Re: [GSBN] SB Overhangs (was Big News!)
>
> Hi Martin
> I certainly don’t envy those trying to create a 1 size fits all
> international building code that balances freedom of design and
> place for innovation with the specifics of good building practice.
> Anyhow to add some further food for thought.
>
> In answering questions about what to do with multi storey designs, I
> always find history to be such a valuable tool when it comes to
> looking at various design responses.
> The vernacular architecture of Japan has evolved a very sensible
> architectural style when it comes to protecting their thin little
> earth plastered wattle and daub structures. Numerous numbers of
> these structures still exist with some are many hundreds of years
> old, with some being even 3 or 4 storeys high of earth plaster!! The
> roofs are often but not always hipped, affording good overhangs all
> around and in the case of multi storey buildings each floor has its
> own min roof around it like skirts.…so shedding the rain at each
> level. In the case of gabled wall ends, all the openings have min
> roofs over them. Other times the clay wattle and daub is given a
> basic plaster and then an external timber siding rather than more
> plaster is used. Effectively parapet walls are generally avoided so
> the roof always closes over the top of a wall. Even their boundary
> walls, which are usually of more solid packed earth and are
> typically earth plastered, all have mini roofs over the tops of the
> walls ….usually 1 layer of beautiful crafted fire clay tiles
> overhanging either side with a ridge cap in the centre. Their
> plastered walls are also broken into panels with expressed timber
> framing, so that the plaster surfaces are broken down into
> manageable sizes that can be plastered to absolute perfection and
> generally present much fewer problems with cracking.
>
> I am not familiar with the extent or wording of the code, so I may
> be speaking out of context but generally I would be worried about
> being overly prescriptive about how one solves a
> problem ....especially where officials can take a narrow
> interpretation of a code and there may be ways and new products that
> have not been thought of yet that may offer alternate solutions?
> While I agree having roof overhangs is best practice and I have not
> done otherwise, it may be wiser that one set about defining what one
> is trying to do that a roof overhang is doing…i.e. not letting water
> get in from the top being the most critical clearly….. or is one
> trying to give the wall some degree of protection from rain hitting
> it by using an overhang as well? Because outright protection I don’t
> believe is practical or even necessary. I think the degree or amount
> of overhang is more of a regional thing that is even specific to the
> exact context of the site of the building… the intensity of rain
> that is potentially hitting a wall and the direction that it comes
> (rain does not always come from above) are clearly important factors
> to try and understand and respond to and will vary from place to
> place.
>
> Context will change things and how one designs in relation to the
> context …..so I would imagine some of what the code needs to
> address would be how design may respond differently in relation to
> the amount of rain, wind direction, wind driven rain (if
> applicable), rain intensity, when it rains in relation to how cold
> or hot it is, so one understands how quickly or otherwise rain may
> be able to dry out again. The position of ones overhangs and rain
> buffers (pergolas, shade devices etc) and use of rain screens may be
> of more importance depending on where and how big one designing……the
> rain here in the Cape is typically winter rainfall that is wind
> driven almost always coming from the North west….and in some cases
> comes in horizontally especially along the coast. In these cases one
> has to look at incorporating siding over the bales and rain screens
> on the exposed sides to help shield the rain….and in certain cases I
> will avoid using straw in the parts where it is too at risk….so I
> rarely end up with a building with 100% of its walls being in straw
> bale.
>
> Best
> Andy Horn
>
> ECO DESIGN – Architects & Consulatants
> 6th floor, 79 on Roeland, 79 Roeland St.
> 8001, CAPE TOWN, SOUTH AFRICA
> Tel: 07 21 462 1614, fax 07 21 461 3198
> website: www.ecodesignarchitects.co.za
>
>
> From: GSBN-bounces at greenbuilder.com [mailto:GSBN-bounces at greenbuilder.com
> ] On Behalf Of martin hammer
> Sent: 25 August 2010 02:50 PM
> To: (private, with public archives) Global Straw Building Network
> Subject: Re: [GSBN] SB Overhangs (was Big News!)
>
> Hi Graeme,
>
> I’ll send you the SB code off list.
>
> Re: the overhangs, what do you do with multi-story or tall walls?
> Do you have roof at typical first floor ceiling height in addition
> to the upper roof?
>
> I will definitely consider putting such a table into the SB code. I
> saw Bruce’s vote of agreement, and wonder if anyone else strongly
> agrees or disagrees that overhangs be code-mandated for strawbale.
>
> Overhangs are generally a very good idea for SB, and I consider them
> “good practice” or “best practice”. I don’t know if they are at the
> level of “minimum practice”, which is typically the threshold of
> code language, although all of that is open to considerable
> debate. Also in your table you account for wind as a factor, but
> not rainfall. If your table were applied to desert climates, it
> might be unfairly restrictive (although some desert climates receive
> concentrated periods of rain).
>
> In an earlier iteration of the code I prohibited strawbale parapets,
> but for a few reasons decided to instead be silent on the issue.
>
> Martin
>
>
> On 8/24/10 4:11 PM, "Graeme North" <graeme at ecodesign.co.nz> wrote:
> HI Martin
>
> firstly my congratulations -
>
> and yes, I would really appreciate a word document I can make
> comment on
>
> >From my neck of the woods, one of the overriding issues I encounter
> time and time again is that of good weather protection from wind
> driven rain in our decidedly pluvian and humid climate - something
> that gets skittered around in most books and references.
>
> I think we need a prescriptive starting point. In the NZ Earth
> Building Standards NZS 4299 we relate wind zone. eaves height
> (vertical exposed wall height), and roof overhang width to give
> MIMIMUM roof overhangs as follows -
>
>
> Wind Zone - Ratio of eave height to width
> Low (at ULS 32m/s) 4:1 (600mm over a 2400 wall)
> Medium (37m/s) 8:3
> High (44 m/s) 3:2
> Very High (50 m/s) 1:1 (or in other words a full verandah)
>
>
> We developed this table after leaks and some degradation of material
> in some earthen structures and I can report that there has been no
> reported problem since we adopted this.
>
> It is my contention that straw buildings are at least as moisture
> sensitive as earthen buildings and I would suggest that this sort of
> table be regarded a good starting point for calculating minimum roof
> overhangs for direct-plastered external strawbale walls, a
> recommendation that could possibly be worked back (or exceeded)
> after local weather or site assessment, or possibly a service
> history of locally developed techniques.
>
> It may seem a but draconian to some but for my money the biggest
> problem with strawbale buildings, in humid wet climates at least,
> seems to be that of providing adequate primary weather protection,
> in the form of eaves, or rain screening, and lack of good practical
> prescriptive guidance on this subject.
>
>
> Comments welcome
>
>
>
>
>
> Graeme (in bossy standards writing mode) North
>
> Graeme North Architects
> 49 Matthew Road
> RD1
> Warkworth
> tel/fax +64 (0)9 4259305
>
> graeme at ecodesign.co.nz
> www.ecodesign.co.nz
>
>
>
> On 23/08/2010, at 5:32 PM, martin hammer wrote:
> Everyone,
>
> Lars Keller asked the below question so I thought I would answer to
> all in case others are interested. I’ll set a deadline of September
> 30th for anyone wanting to comment on the strawbale code as in the
> second draft of the IGCC.
>
> Thanks.
>
> Martin
>
>
> On 8/22/10 9:36 PM, "Lars Keller" <larskeller at gmail.com> wrote:
>
>
> Dear Martin,
> What is the deadline for comments to you ?
> Best regards,
> Lars Keller
>
> On 22 August 2010 03:36, martin hammer <mfhammer at pacbell.net> wrote:
>
> Hello friends on the GSBN,
>
> My voice has been conspicuously absent on this subject, so I
> thought I would weigh in.
>
> First, thanks for the words of appreciation. I was pleasantly
> surprised to hear the news from David on Monday. I think this
> strawbale code document is very good, but there are a number of
> reasons I didn’t think it would go through to the next step. I
> thought both the Earthen Materials proposal (referencing the
> recently revised ASTM standard that Bruce, David in earlier years,
> and others worked so hard on) and the Straw-Clay proposal I co-
> authored with Paula Baker-Laporte, had better chances. I might
> propose them again in the upcoming Code Change Proposal phase (once
> IGCC committee concerns are addressed).
>
> Much blood, sweat, and a few tears have gone into this SB code
> since 2003, when I began writing it at the request of the State of
> California (they asked Bruce, Bruce asked me . . .). I’ve had very
> good input from others along the way, including members of this list
> (David Eisenberg, Bruce King, Dan Smith, Bob Theis, Tim Kennedy,
> John Swearingen, Bill Steen, Kelly Lerner) (apology if I’ve missed
> anyone), and others not on this list, notably civil engineering
> professor Mark Aschheim.
>
> Because it started as a California code, and because there are
> great SB experts in northern CA where I live, the code might be a
> bit California-centric (with particular attention to seismic
> issues). However I’ve always wanted it to be broadly applicable and
> I welcome broader, global input at this time. I expect to propose
> adjustments during the next IGCC review phase. If it remains in the
> IGCC and goes the way codes often do, some version of this might
> show up at your building official’s door and then your strawbale
> door in Australia, South Africa, or who knows where. And although I
> think there’s much to like, I can almost guarantee you can find
> something you don’t like. So . . .
>
> If you want to see and comment on the proposed code you can ask me
> to e-mail the proposed SB code (by itself) to you as a word
> document, and then e-mail me your comments or send it back with
> “track changes”. OR you can go to: http://www.iccsafe.org/CS/IGCC/Pages/Comments0810.aspx
> , and download all Public Comments under the “Complete Document”
> subheading (Strawbale Construction is Comment #5-136). You can then
> e-mail your comments to me (not to ICC). I’m also open to comments
> on #5-134 Straw-Clay, and #5-135 Earthen Materials. If you want to
> understand the IGCC process and schedule, you can go to:http://www.iccsafe.org/cs/IGCC/Pages/PublicVersionDevelopment.aspx
>
> In addition, I want to clarify that:
>
>
> Strawbale is not yet in the IGCC. That’s because it isn’t finalized
> (and SB could even be entirely removed).
> Even if included in the final version, the IGCC applies only to
> commercial and high-rise residential, AND only in jurisdictions that
> adopt the IGCC. So it would have limited application.
>
>
> That said, this approval is still a very good thing. And if it
> does make it to the finish line of the IGCC, it would probably then
> migrate to the IBC in the next code cycle, and then to a
> jurisdiction near you. I even see the possibility of jurisdictions
> adopting it or informally using it for all occupancies, even before
> reaching the IBC. John Swearingen’s report of it already producing
> “instant results” for his project in Stanislaus County supports that
> notion, and is both welcome and frightening.
>
> Finally, I want to acknowledge David Eisenberg and Matts Myhrman
> who together forged the first SB code in Arizona in the early-mid
> 1990’s, and to David again for speaking so convincingly on behalf of
> the current proposed code at the recent hearing in Chicago. If you
> read his description of what he said, you’ll see that he simply told
> the compelling truth about the most relevant issues. It’s one of
> many things David does so well. It’s nice when the compelling truth
> prevails (at least for now).
>
> Thanks David, and thanks to all. And thanks to the enduring spirit
> of strawbale!
>
> Martin
>
> PS - For a pre-IGCC history of this SB code, see my GSBN post on
> Dec. 1, 2009. Reviewing that e-mail might also be used as a natural
> aid to help you fall asleep. However, for me it is a riveting drama
> (sometimes moving at the pace of a melting glacier . . . actually
> that’s happening quite quickly these days!)
>
>
>
>
> On 8/16/10 10:13 PM, "strawnet at aol.com" <strawnet at aol.com> wrote:
>
>
> Hello all,
>
> I want share some great news. Earlier today, here in Chicago, Martin
> Hammer's "comment"/proposal to include the strawbale code he’s been
> working on over the past few years in California into the new
> International Green Construction Code (IgCC) was approved by a
> committee vote of 8 to 6! The IgCC is the new US code for commercial
> (and high-rise residential) buildings that will become part of the
> family of 2012 International Codes (I-codes). It will go through a
> full code development cycIe with the rest of the 2012 I-codes next
> year and there is work that will need to be done still to make sure
> it doesn’t get rejected in that process, but getting it into the
> second public draft of the code now is a very big step forward.
>
> I served on the drafting committee for this code from last summer
> through the spring of this year. For more information about the IgCC
> and to download the whole IgCC first public draft and the comments –
> including Martin’s proposals for strawbale and earthen building and
> the EcoNest comment in support of straw clay go here:
> http://www.iccsafe.org/cs/IGCC/Pages/default.aspx
> http://www.iccsafe.org/CS/IGCC/Pages/Comments0810.aspx
> You’ll find these listed as comments 5-134, 5-135 and 5-136.
>
> I was the only proponent speaking in favor of it here, and there
> were others who spoke in opposition. The initial motion was to
> disapprove but it failed 5 votes to 9 after considerable and very
> mixed discussion – which surprised me because of the nature of some
> of the comments – that it was still not ready and needed some
> technical fixes.
>
> The failure of the motion to disapprove required a new motion and
> Chris Mathis, an old building science friend from North Carolina,
> offered a motion for approval. That was followed by more discussion,
> with more concerns expressed that it wasn't ready. Then, just before
> the second vote, Chris pressed the committee to push the envelope.
> He said they should approve it and get it in, and rather than just
> having the few people who are very knowledgeable about it work on
> improving the things that still need to be done, “Let thousands of
> people look at it and help improve it through the next round of the
> code development process!” He said it was time to start pushing
> these things through. Then they voted - and it passed 8 to 6! I was
> amazed and delighted! So it is going into the second public draft!
>
> There were two other similar proposals (they’re called “comments”)
> that were heard right before the strawbale comment. The first, from
> Paula Baker Laport and Robert Laport proposed including the straw
> clay guidelines fromNew Mexico. Next was the other submitted by
> Martin, that one in support of earthen construction based on the new
> ASTM standard for earthen wall systems that I had initiated almost
> 10 years ago and Bruce King has spearheaded over the past few years.
> I spoke in support of both, but they were disapproved, though both
> received encouraging suggestions to bring them forward again after
> addressing non-mandatory/permissive language and other issues.
>
> Because they were heard one after the other, and I was the only
> proponent for them, I got to speak first for each one and so I had a
> total of 6 minutes (2 minutes each) to frame them all in terms of
> the big issues I’ve been speaking to for all these years, including
> the coming challenges of ever-more limited and expensive energy, the
> low-impact, low-tech, climate beneficial, local/regional benefits,
> the industrial/proprietary bias and difficulty in funding research,
> testing and development for public domain, non-proprietary materials
> and systems. I started off by talking about the fact that I had been
> in buildings in Europe built with materials like straw clay and
> earth that are twice as old as this country! And to say that these
> are durable and safe ways of building when done properly. And when
> talking about the ASTM earthen standard, I said that if they looked
> at it they might think that it was too low tech to be reasonable
> compared to the standards that they’re used to for concrete and
> other industrial materials. But, I said, It was intentionally low
> tech. That I was involved in initiating that standard almost ten
> years ago and it was both to enable the use of those materials here
> and to reverse the outlawing of earthen building in developing
> countries through the adoption of modern industrial codes. That it
> was designed to enable people to build safe, durable, healthy, and
> affordable buildings anywhere in the world—including the in United
> States. I mentioned that the committee that developed that standard
> included the leading experts on earthen building and engineering
> from around the world and was based on reviewing and incorporating
> the best from international codes and standards for earthen building.
>
> After the first two went down, I was quite convinced because of the
> comments that the sb proposal would share the same fate and,
> thankfully, I was wrong!
>
> So hats off to Martin, Bruce, Matts, and many others who have
> worked so long and hard to develop these codes and to Chris Mathis
> for his leadership and visionary action on the committee.
>
> Onward!
>
> David Eisenberg
>
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