[Cob] buttresses without foundation plan

[Tys Sniffen]

Malcom, 

We, too, added buttresses after we did the fundamental circumference wall.   What I did was dig a trench for gravel - but didn't put any French drain pipe under it, and then put the typical urbanite stem wall up - mortared together and mortared TO the other stem wall - and then put in the buttress AS we built up the wall. 

That is, while the stone stem wall isn't really tied in to stone stem wall of the house, the cob completely is.  The buttress went up at the same rate as the wall. 

It's been something like 5 years since those buttresses were cobbed in, and no settling cracks or any trouble at all. 

Ideally, you'd tie the stem walls in with interlocking rocks. 

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Today's Topics:

   1. cob greenhouse strawbale (dhowell at pickensprogressonline.com)
   2. Re: cob greenhouse question (Malcolm Schluenderfritz)


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Message: 1
Date: Thu, 24 Sep 2015 13:21:28 -0400
From: "dhowell at pickensprogressonline.com"
	<dhowell at pickensprogressonline.com>
To: mschluenderfritz at gmail.com
Cc: "coblist at deatech.com" <coblist at deatech.com>
Subject: [Cob] cob greenhouse strawbale
Message-ID:
	<E42F5987-1D7A-480F-886A-42D8339AEF37 at pickensprogressonline.com>
Content-Type: text/plain; charset=us-ascii

Malcolm,
	"could the buttresses be straw bale walls?"
	No. Being that the purpose of a buttress is to support a wall from shear forces. How is a straw bale wall going to support a cob wall when the cob weighs probably a hundred times more than straw bale? It's not going to amount to much resistance should that cob wall come crashing down.

Damon


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Message: 2
Date: Thu, 24 Sep 2015 13:15:58 -0600
From: Malcolm Schluenderfritz <mschluenderfritz at gmail.com>
To: john fordice <otherfish at comcast.net>
Cc: coblist at deatech.com
Subject: Re: [Cob] cob greenhouse question
Message-ID:
	<CALUHa8kznP2-bSpoN_WmNwTf8yta6T7R81SUnugGkpHXvTq5kw at mail.gmail.com>
Content-Type: text/plain; charset=UTF-8

Thanks for the advice. I guess then I will make the buttresses out of cob and and bales separately for insulation.

Another question; The rubble trench, reinforced concrete bond beam and urbanite stem wall for this structure have already been built. And since I did not have buttresses in my original plan, they are not represented in the foundation. Will they still work if I put in separate rubble trenches and stem wall for them, since they will not be connected to the main wall foundation?

Malcolm

On Thu, Sep 24, 2015 at 10:15 AM, john fordice <otherfish at comcast.net>
wrote:

> Mqlcome,
> Cob and strawbale walls act very differently to loads & while 
> strawbale can be added over cob for insulation, I would not mix them structurally.
> Not a good idea.
> john
>
> On Sep 24, 2015, at 6:39 AM, Malcolm Schluenderfritz < 
> mschluenderfritz at gmail.com> wrote:
>
> Hello John,
>
> Thanks again. One more question: could the buttresses be straw bale walls?
> I am thinking that the buttresses protruding from the back wall could 
> be used as a chicken coop, which would benefit from heat from the cob 
> wall, and insulate the greenhouse. I would already have three walls 
> and the roof overhang.
>
> Yours,
> Malcolm
>
> On Wed, Sep 23, 2015 at 11:11 PM, john fordice <otherfish at comcast.net>
> wrote:
>
>> Hi Malcom,
>> Yes, the freestanding ends of your walls and midpoint of the long 
>> back wall should still be buttressed.  I?d suggest putting the 
>> buttresses on the outside surface of the walls & thus leave the 
>> rtransparent greenhouse walls fully open to sunlight.
>> Small p[eces of urbanite should be ok, just don?t make them any 
>> bigger than 2 - 3 ?.
>> john
>>
>> On Sep 23, 2015, at 3:14 PM, Malcolm Schluenderfritz < 
>> mschluenderfritz at gmail.com> wrote:
>>
>> Hello John,
>>
>> I modified the design. Now the tallest cob wall will be 6 feet. Do I 
>> still need buttresses?
>>
>> I will leave out the urbanite chunks then. Would small pieces of 
>> rubble less then two inches across be OK? I was wondering if they 
>> would act like large gravel.
>>
>> Thanks for your help.
>>
>> Malcolm
>>
>> On Sat, Sep 19, 2015 at 10:18 PM, john fordice 
>> <otherfish at comcast.net>
>> wrote:
>>
>>> Malcome,
>>> A few suggestions relating to the cob:
>>> 1. Buttress the open ends of your rear & left end walls.  Make the 
>>> buttress?s 3 or 4? long at the stem wall & zero at the wall top.  
>>> Add an intermediate buttress at the midpoint of the rear wall.
>>> 2. Batter your walls to 12? thick at the top & 18? at the stem wall.
>>> 3. Do not put pieces of urbanite in the cob ?? bad practice !
>>>
>>> This is relative to the cob only ??? the framing of the transparent 
>>> materials support is another story ?? sounds like the loads of the 
>>> wood & plastic roof / walls will be minimal, so as long as you don?t 
>>> have heavy concentrated loads either embed your rafters in the cob or add a top plate
>>> with deadmen in the wall.   Assuming you know how to make competent cob &
>>> build correctly ??? if not, get advice of an experienced cobber.
>>> john
>>>
>>> > On Sep 19, 2015, at 9:51 AM, Malcolm Schluenderfritz <
>>> mschluenderfritz at gmail.com> wrote:
>>> >
>>> > ---------- Forwarded message ----------
>>> > From: Malcolm Schluenderfritz <mschluenderfritz at gmail.com>
>>> > Date: Fri, Sep 18, 2015 at 8:40 PM
>>> > Subject: Re: [Cob] cob greenhouse question
>>> > To: Howard Switzer <howard at earthandstraw.com>
>>> >
>>> >
>>> > Hello Howard,
>>> >
>>> > Thanks for the advice.
>>> >
>>> > I will try to post a plan soon.
>>> >
>>> > I am stuck with the 18" base because the foundation is already 
>>> > build. I agree that it seems something is needed at the North East corner.
>>> >
>>> > The concrete is to use it up and to speed drying on the wall. (An 
>>> > idea
>>> from
>>> > "The Hand Sculpted House." ) I got huge loads of broken concrete
>>> dumped for
>>> > the foundation and for retaining walls on other parts of the site.
>>> These
>>> > are pieces that are fairly good but not quite square enough for 
>>> > those
>>> uses.
>>> > Spaced widely (so that they do not form problematic joints) in the
>>> core of
>>> > the wall, it seems that they will allow me to use less cob, which 
>>> > not
>>> only
>>> > means faster drying, but also less cob mixing and less purchased 
>>> > sand
>>> use.
>>> >
>>> > I would think that if cob is strong enough to arch over small 
>>> > niches,
>>> it
>>> > would be strong enough to take a few pieces of concrete inside the
>>> wall.
>>> > But correct me if I am wrong.
>>> >
>>> >
>>> >
>>> > On Fri, Sep 18, 2015 at 8:29 PM, Howard Switzer <
>>> howard at earthandstraw.com>
>>> > wrote:
>>> >
>>> >> I know John will take good care of you, (do post your plan if you
>>> can) but
>>> >> basically you got a 16 foot wall braced on one end, right, so 
>>> >> sounds
>>> like
>>> >> you need to brace the other end somehow. Now I expect there will 
>>> >> be
>>> an east
>>> >> wall so you might consider bracing it in such a way as it could 
>>> >> serve
>>> to
>>> >> buttress the end of the wall and you might want to embed some 
>>> >> anchors
>>> in
>>> >> the cob for attaching that bracing wall....or you could just do a 
>>> >> cob buttress off the end of the wall in the other direction, 
>>> >> which is
>>> probably
>>> >> the better option, just guessing. You might also want to consider
>>> battering
>>> >> the wall a bit, wider (20") at the bottom than the top (16"), right?
>>> Might
>>> >> add some more stability. What are the concrete pieces doing in 
>>> >> the
>>> middle
>>> >> of it?  Just trying to get rid of it or something?
>>> >>
>>> >>
>>> >>
>>> >> On Fri, Sep 18, 2015 at 2:31 PM, Malcolm Schluenderfritz < 
>>> >> mschluenderfritz at gmail.com> wrote:
>>> >>
>>> >>> I am building a small greenhouse, 16 feet by 8 feet, and 8 feet
>>> tall. The
>>> >>> North and West walls will be cob, and about 18 inches thick. I 
>>> >>> will
>>> be
>>> >>> inserting some pieces of concrete as we go, in the center of the
>>> wall. The
>>> >>> walls are straight, not curved.
>>> >>> Do I need to add buttresses to this wall to keep it up, or is it
>>> thick
>>> >>> enough? The North and West walls already form a corner, so they
>>> provide at
>>> >>> least a little Lateral support to each other.
>>> >>> _______________________________________________
>>> >>> Coblist mailing list
>>> >>> Coblist at deatech.com
>>> >>> http://www.deatech.com/mailman/listinfo/coblist
>>> >>>
>>> >>
>>> >>
>>> >>
>>> >> --
>>> >> Howard Switzer - Architect
>>> >> 668 Hurricane Creek Road
>>> >> Linden, TN 37096
>>> >> 931 589 6513
>>> >> www.earthandstraw.com
>>> >>
>>> >> ?You never change things by fighting the existing reality.
>>> >> To change something, build a new model that makes the existing 
>>> >> model obsolete.?
>>> >> ? Richard Buckminster Fuller
>>> >> <
>>> http://www.goodreads.com/author/show/165737.Richard_Buckminster_Full
>>> er>
>>> >>
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> > --
>>> > Malcolm Schluenderfritz
>>> > Secretary,
>>> >
>>> > The Saint Isidore Society,
>>> > saintisidoresociety.wordpress.com
>>> > _______________________________________________
>>> > Coblist mailing list
>>> > Coblist at deatech.com
>>> > http://www.deatech.com/mailman/listinfo/coblist
>>>
>>>
>>
>>
>> --
>> Malcolm Schluenderfritz
>> Secretary,
>>
>> The Saint Isidore Society,
>> saintisidoresociety.wordpress.com
>>
>>
>>
>
>
> --
> Malcolm Schluenderfritz
> Secretary,
>
> The Saint Isidore Society,
> saintisidoresociety.wordpress.com
>
>
>


--
Malcolm Schluenderfritz
Secretary,

The Saint Isidore Society,
saintisidoresociety.wordpress.com


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