[GSBN] SB Overhangs (was Big News!)

[Sarah Johnston]

Hello all.

We agree that eaves are very important and also feel there should be a  
minimum eave depth included for a SB code, the difficult part is  
making it appropriate for all climates.

With our experiences with projects in dry, windy parts of NZ we do  
disagree with the concept of making the eaves oversized in the code  
then have industry professionals argue to have smaller eaves if they  
wish.  This approach creates a challenging situation for design  
professionals and code officials who end up having to put themselves  
in a vulnerable place from a liability perspective just to get to a  
realistic eave depth for the climate they are working in.  This  
approach creates a lot of extra work as well.

A BIG congratulations for all your great work and thanks to everyone  
involved in the code effort!  We would most certainly appreciate a  
copy of the present draft code to have a look at.

Warm Regards,
Sarah & Sven Johnston

Sarah Johnston
Sol Design, Ltd.
50A Connolly Street
Geraldine New Zealand
03 693 7369
sarahjohnston at ihug.co.nz

On Sep 1, 2010, at 11:53 PM Sep 1, 2010, Graeme North wrote:

> There are many ways to give a strawbale wall primary weather  
> protection - the trick is to make sure that it happens, and this is  
> what a Standard can do.  Rain screening of some sort is one  
> wonderful method.
>
> What I despair of is designers who appear to think that they are  
> "getting away" with something (what?) by leaving good prudent  
> primary weather protection off their buildings.
>
> I prefer to sleep on wet windy stormy nights.
>
>
>
> Graeme
> Graeme North Architects
> 49 Matthew Road
> RD1
> Warkworth
> tel/fax +64 (0)9 4259305
>
> graeme at ecodesign.co.nz
> www.ecodesign.co.nz
>
>
> On 1/09/2010, at 11:52 PM, Rikki Nitzkin wrote:
>
>> 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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