permaculture

[Cliff Davis <spiralridgepermaculture@gmail.com>]

What about good old cedar, black locust or sassafras.  Not only do we not
know the effects of PT wood it feeds the desmon of industrial logging and
forestry management practices better known as clear cut which creates
deserts.  Just sayin!  Look around.  Are there any mills near you?



On Mon, Jan 21, 2013 at 10:59 PM, Stephen Sherman <spsherm@msn.com> wrote:

> I think you'll find that the commercial double glass pane units are air
> evacuated and filled with an inert gas. That makes the "middle" less
> conductive and convection loops less of an issue, which is why they can
> have 1" spacing without loosing insulating, I suspect. Unfortunately
> this is not really doable on a wood framed unit.
>
> Look carefully at the total system cost of two 1/8" sheets of polycarb
> vs the commercial dual or triple wall polycarb GH extrusions. When I
> last compared prices (granted a few years ago) the roll your own
> polycarb solution was quite a bit more expensive; which makes sense
> since you end up using 1/4" thickness of plastic overall. The commercial
> GH extrusions are quite a bit thinner than that, and use less plastic
> per sq ft of coverage.
>
> One can still put the multi-walled GH extrusions on a treated 2x frame,
> much the same way you would the single wall, you just are putting it on
> only one side of the wood structure. In CO, all new treated lumber is of
> the newer non-arsenic type for quite a few years now. I thought it was
> everywhere but you probably need to check. (The new stuff gives a
> reddish brown color to the wood, as compared to the old stuff which made
> the wood a greenish color.)
>
> Whatever polycarb you go with, you should be sure to get some which has
> a UV protected surface coating, and be sure to put that towards the
> outside as you are installing. Failure to do so will mean your plastic
> will not last as long when exposed to the sun. No plastic (clear plastic
> at least) will last forever when exposed to direct sunlight. Up here at
> 8200' elevation, the GH plastic I have has lasted 10 yrs so far and is
> still quite functional. Some say you can get 20 yrs out of it (it is
> guaranteed for 10). Interior (non UV protected) start whitening and
> cracking in as little as 5 yrs. No doubt all these times will be longer
> in places with less UV and sun.
>
>
>
>
> On 1/18/2013 9:26 PM, venaurafarm wrote:
> > On 1/18/2013 11:03 PM, Scott Pittman wrote:
> >> I have always read that any airspace between the glass or poly should
> never
> >> exceed 5/8 of an inch to prevent a thermal loop from developing which
> would
> > There is plenty of glass double pane panels that have 3/4" airspace.
> >
> >> defeat the purpose of double glazing.  This is certainly the rule in
> >> manufactured thermal pane windows and doors.  By evacuating the air
> space
> >> between the glazing panels you can slow down this effect with over time
> the
> >> vacuum gets lost.
> > My method just uses two Polycarbonate glazing attached to framing
> > members, not air evacuated. My untested theory on prevention of thermal
> > loops would be to use more framing members, blocking more light of
> > course but creating a stronger panel that is more energy efficient. I
> > would not hesitate to use this method on a skylight, in a sunspace or
> > or a greenhouse. This by far the cheapest way to go plus extremely
> > durable and lightweight; you get plenty of light with some degree of
> > thermal efficiency.
> >
> > LL
> >
> >
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-- 
*
*
*Cliff Davis & Jennifer Albanese
Spiral Ridge Permaculture
www.spiralridgepermaculture.com
931-231-4099*


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