[Strawbale] Foams

[David Neeley]

In the U.S., most of the metal roofing materials can be pre-finished
at the factory with a very durable painted surface. If this is an
option for you, tests at the Florida Solar Energy Center have
determined that a bright white is better than a shiny metal surface.

On the other hand, if you had a shiny reflective surface on the
*bottom* of the sandwich panels, it would face air (the room below!)
and would function as a radiant barrier.

Thus, if efficiency is the key for you, white on top and reflective on
the bottom would seem ideal--if you can live with the idea of a
metallic ceiling, of course.

I would also contemplate using a good foam to fill the gaps between
the ceiling panels and your outer walls. That would be the only way I
can think of offhand to be sure you have no air leakage, which as Doug
has indicated is often a very important consideration. In North
America, there are do-it-yourself foam kits that use a foam created
from soybeans that is still very good insulation.

David



On 7/19/06, Andrew Webb <design at thegreenwebb.com> wrote:
> Hi Doug,
>
> Your points are valid and you are right that reflectivity is important
> in this climate.  That is another potential problem with sandwich panels
> because there is no air space in the system to have a reflective layer.