bb,

First of all, forget the influence of your structure on light intensity.
The degree of reduction will be insignificant.

Different manufacturers may very well have different transmission levels in
their polycarbonate (note the "a") sheets.

How much light you need depends on the types of plants you grow, and is
affected by the direction your shade house will face, among other factors.

From my standpoint, I'd go with clear, and then use the
much-cheaper-and-easier-to-replace shade cloth to control the light levels.
Imagine the work and expense of selecting and installing one particular
roofing material only to discover that it doesn't let in enough light! You
can always add more shade cloth!

--

Ray Barkalow First Rays Orchids
http://www.firstrays.com
Secure Online Ordering & Lots of Free Info!


"bb" wrote in message
...
I'm in the process of building a lean-to orchid house and can't seem
to decide what is the best roof panel to use. If anyone has any
experience I'd appreciate opinions.

I'm on the west coast of central Florida so we have abundant sunshine.
The structure of the orchid house is of pressure treated lumber
painted white to help keep it cool. Walls will be screen only. Roof
panels will most likely be polycarbonite with 1X4 and 1X6 perlins
approx every 36". I figure the perlins will cut down a certain
percentage of available light.

My question comes down to the light transmitting properties of the
different shades of panels. From what I can find out, the clear
panels let in 90+ % of the light. I seem to be getting different
stories on the grey and white panels. One manufacture seems to say
it's grey panels let in about 70% of light, while another puts it at
20 percent. Same thing with the white panels, one says 45% light,
the other 65%.

Would there really be a difference between the same thickness and
color of polycarbonite panels from different manufactures?

What would be the preferred amount of light to let through,
considering I'm already going to lose some through the perlin spacing?

The local orchid grower I frequent for supplies recommends the white,
but they sell a prefab pvc and pc greenhouse that uses the grey
panels.

Esthetically, I prefer the grey, but the health of my orchid buddies
comes first.

Anyway, I'm hoping to start installing the roof this weekend, after
about six tedious weeks of building and painting the structure. I
thought I have it figured out by now, but I"m still doubting the
choices. Any input would be greatly appreciated.

bb