[Cob] cob greenhouse question

[Malcolm Schluenderfritz]

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_Fuller
> >
> >>
> >
> >
> >
> >
> >
> >
> >
> > --
> > 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