[Cob] FW: OFF LIST response Cobhouse design

[Phil Moulton]

-----Original Message-----
From: Sher Gorton [mailto:sirslilpony at yahoo.com] 
Sent: Wednesday, April 08, 2009 12:16 PM
To: Shody Ryon
Cc: Phil Moulton
Subject: Re: OFF LIST response [Cob] Cobhouse design


Hi, Shody... Phil's wife lilpony responding offlist:

I am not on this list, I think, so missed the previous posts... so if I'm
way off-base on my assumption that I know what you're referring to, please
correct me! :)

If it's in regard to the SB-or-cob we are planning, we are still firming up
exactly what foundation, what wall material and structure, etc. but at this
point we are considering the lowest-tech, best-efficiency,
easiest-owner-built strategies, and are currently most leaning toward:

1.  Foundation:  Stemwall, poured concrete with rebar reinforcement.  Phil
used the term "monolithic" in regard to foundation as opposed to mortared
stone-or-brick, stacked stone, slip-form or other space-filling strategies
that create non-unified surfaces that can slide against each other in an
earthquake.  We live in the western United States - and our part of the
world is well overdue for a great quake.  Seems prudent to take it into
consideration, and it is a very large consideration for us.  Yes, we
understand that concrete is a very high-embodied-energy material but after
considering pros-and-cons including using chunks of 'urbanite' as filler we
have decided that we are not willing to compromise on the foundation.  Any
of the other elements of our building might be changed, in fact we are still
talking about SB versus cob for walls, but... the foundation will be as
one-single-piece as we can make it.  In order that, should the earth move,
 we increase the possibility that the foundation will shift as a unit.

Personally I am still leaning toward cob rather than SB because of the
above.  Given we tie-in the cob walls to the foundation properly (re-bar
extending up from the foundation?), the entire home can be made pretty
"monolithic" which will also increase its earthquake-resistance.  (And yeah,
we do understand the compromises involved with the large south-facing
window-thing, and planning for timber/beam reinforcement/framing of the
south wall because of the windows, etc.)

2.  Floors:  Earthen/cob floors over tamped roadbase (i.e., 3/4-minus
rock).  Yes we have been talking about putting piping in the floor for heat
because we have a solar hot-water system the buyer of Phil's house did not
want and we both HATE cool/cold floors.  We have, however, been talking
about using the solar system for household hot water - and the probability
that with the thermal gain in the cob floor, or
cob-with-inlaid-tile-or-brick floor (wow, what a mouthful!) we don't need
in-floor heat anyhow.  Considering pumice in one underlayer of the floor for
insulation.

3.  General heating, solar, and woodstove:  There will be partial walls for
thermal mass storage, and for visual space-division as to task/use.  The
house will be south-facing in a more-or-less earthship-style configuration,
i.e. long wall facing south with large windows for solar gain, planters
underneath, short walls with benches for catching/holding solar heat, etc.
etc. etc.  The woodstove is for backup heat/drying out the air in cool/wet
weather - and also for backup cooking should the need arise.  Besides that
we love the 'glow' of woodstove heat and the coziness of sitting around the
woodstove in the evening.  But it would be the primary space-heat (i.e.,
warming the air) as well - we don't like cold air indoors.

Does that give you a little clearer picture?  ...hope so. :)

Phil's "lilpony"

P.S.  The PNW is actually very cloudy, many more cloudy days than in
Michigan.  Warmer here in winter, of course, but not so much sun at ANY time
of year as Michigan - we get constant clouds off the Pacific Ocean, and it's
very humid air here.  We can't always count on the thermal batteries holding
their charge long enough to rely on thermal-mass-heat alone, and most of the
year indoor air could use some drying out just because of the high ambient
humidity.  Then add in the additional moisture of growing salads indoors,
and.... doesn't a woodstove make a LOT of sense?


----- Original Message ----
From: Shody Ryon <qi4u at yahoo.com>
To: tinkasbonus at yahoo.dk; Phil Moulton <philmoulton at gmail.com>
Cc: sirslilpony at yahoo.com
Sent: Wednesday, April 8, 2009 12:14:50 AM
Subject: OFF LIST response [Cob] Cobhouse design


Hi,
It sounds really great and well thought out. If I may, I love radiant
floors, but they are expensive, require fiddling, pH adjustment and are only
useful in an energy inefficient design. I believe this because a super
insulated home with a well insulated envelope has all surfaces at 70 F, so
why bother with a radiant floor.

This can be demonstrated by the R value you are planning to install in the
floor, is it R15?

I can explain how you can improve the heating system, including radiant heat
floors, if you insist, with your house 98% to 100% heated with solar gain.
This will save you from having a gas or elect "boiler" for your system and
will save you from installing PEX or what ever in the floors. "My" system
will be easier to run and maintain, it will change temperature faster, so
you will not freeze after being away for a few days, until the temperature
comes up, and you will boil on an unexpectedly hot night, because you have
low thermal storage in the living space. 

I am not following the wood stove as the primary system, would it heat the
water for the floor? would it run on fire wood? What fire/water interface
would you use? Why not use solar as the primary heat? It can be done in
michigan, which is a lot colder and a lot cloudier than your location.

I am not sure what monolithic means to you and what you are referring to as
stronger because it is monolithic. It is strong, but it is not a lot
different that standard foundations witch could be built stronger than an
"average monolithic" foundation/floor. 

If you are going to install super insulation in the floor, it can get
expensive to that under a concrete floor/foundation, which had high embedded
energy and releases 2 pounds of light weight (large amount) of CO2 for every
one pound of heavy (small amount) concrete that is made. 

Concrete should be minimized, because it is expensive, not so good for the
environment, is not so beautiful and usally has some covering, and adds
little besides strength, weight and damage resistance to water exposure, but
it is usually installed poorly and wicks moisture into the living space, so
installing it properly requires lots of gravel and perforated pipe with
proper fall (many installers [I am talking about the actual guys or gals in
the trenches placing the pipe] are not careful) draining to day light or to
a properly constructed dry well in soil that drains. All this for a high
maintenance, slowly responding, energy inefficient, bad for the environment
floor and heating system?  

I am not sure if you are interested in my opinion, so otherwise, good luck
on your project! If you can tell me I am wrong and convince me, I would like
that, because I love warm floors and nice cool air, and I will build your
system, but I think I am right, and I think you will agree with me.

Another thing I think SB walls will add more expense to your project that
you realize. While there are lots of things I like about SB building, I
think you should add up the expense of the extra foundation and roofing with
a vary large overhang to protect the earth plaster from rain and perimeter
length, extra work on the window bucks and see if you would be better off
dollar wise with cellulose. Of coarse some people just want SBs, so that's
that, as long you know it may be costing more than double wall standard wood
framing and at least SB building is not bad for the environment, if it has a
high R value floor and roof and and uses solar gain, as some of what you
plan to do.

Shody