[Cob] radiant floor tubes in clay floor: insulation?

[catrambull]

Hi, I am pretty new to all of this, but am always very interested in these
discussions and read my coblist emails avidly. Re; thermal mass, insulation
and flooring, I have come across a very interesting alternative building
technique called "annualized geo solar" that stores passive solar heat gain
in the earth under the house during the summer (which cools the the house)
and heats the house during the winter. The system seems easy to do, great
for northern climates and may be good for your situation. Here is the link:
http://www.greenershelter.org.  I would love to hear anyones feedback on
applying this system for cob buildings in northern climates. Thanks! Sean

On Thu, Feb 5, 2009 at 4:30 PM, Shody Ryon <qi4u at yahoo.com> wrote:

>
>
>
> --- On Thu, 2/5/09, Tys Sniffen <tys at ideamountain.com> wrote:
>
> > From: Tys Sniffen <tys at ideamountain.com>
> > Subject: RE: [Cob] radiant floor tubes in clay floor: insulation?
> > To: qi4u at yahoo.com
> > Date: Thursday, February 5, 2009, 1:57 PM
> > I hear you on the 'more insulation would be more
> > efficient', unless by
> > insulating my floor away from my stem wall I'm cutting
> > down on my total
> > thermal mass I'll be heating up, thereby not storing as
> > much when I'm
> > putting heat in, thus losing more quickly when I'm not.
>
> When I think of more insulation, I am thinking of including thermal mass. I
> think the best design of thermal mass is to have a lot, or even most of it,
> in it's own insulation envelope separate from the living space insulation
> envelope.
> In a mild climate, this is less important and you mind as well use the
> thermal storage of the cob to it's advantage; insulate exterior to it and
> any and all other structures at the perimeter and create an insulation
> envelope, not just at the walls and roof, but under the floor, as you have
> indicated.
> the straw under the floor has been debated on some other lists recently.
> There are some that think it is a bad idea to have straw below grade in a
> manor that allow it to get wet. This may seem obvious or easy to deal with
> but apparently it is difficult to do this well; in a way that preserves
> straw long term. Some insist that every time it has been documented it has
> failed, as I understood it. I did not really follow along with the posts
> that closely, but that is what I think some prolific posters were saying. So
> I think it is would be good to make sure, one way or the other.
>
>
> > I know I'm not going to put store-bought insulation
> > under the entire floor;
> > I will put a lot of straw in my sub-floor though. The only
> > question is
> > whether to put store-bought stuff maybe a foot in
> > (horizontally) from the
> > wall and whether to put some vertical or not.
>
> I assume mixing the straw with the mud is a good strategy, especially
> obviously if it is a known subfloor technique.
>
> > Being the cheap, all-natural-wannabe that I am, I'd
> > like to skip this step,
> > but my wife is thinking differently.
>
> So there is a trade off, burning gas is not all that "natural" so you will
> apparently be using one or the other, one once and the other every time it
> gets cold, depending on the efficiency of the solar heating system/thermal
> storage.
>
> > Our roof will be pretty strong: minimum R value for our
> > area is 19, we'll
> > have R28 insulation under a steel roof and a 2 inch air
> > gap.  It'll be
> > better insulation than our cob walls.
> > Tys
> code minimums are minimums based on not much. code minimums used to not
> address insulation at all. In the future they will be higher than they are
> now.
> I wonder if are you ok being very hot? I think it gets very hot in some
> areas of northern california, if you are in a hot area R 28 seems like it
> might be low. Are you going to run an AC system? If so, you might use a heat
> pump for most of the heating. What if you could have insulation at a rate
> that eliminate the need for heating or cooling? Accept for the solar system
> for heating? I am not sure this is practical for a cob project.
> If you wanted to have additional thermal storage for heating and cooling
> air in your house you might consider
> http://thermalattic.com/
> It doesn't show it yet but can be used to cool in hot weather.
> Shody
>
>
>
>
>
>
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