Hi folks,
In the back of my yard is an ~8 foot tall south-facing concrete block wall [neighbors on the other side have a swimming pool] that gets sun exposure all day long. In our sunny [even in winter] climate, this wall gets a lot of solar gain. I am considering building a lean-to greenhouse in front of it. I figure that I can build something 16 feet wide by 6-8 feet deep.

I am thinking of a pretty permanent structure...wood frame, polycarbonate panels or tempered glass, and possibly a concrete floor

We get snow occasionally here, but not as much as these poker players have to deal with:



:-)
Anyway, I 'm trying to decide how much pitch to give the roof.
Any ideas? Thanks for your help.

Hilarious!

Hi paulandirene,

You seem to doing exactly as I did 10+ years ago;
building a lean-to (treated) wood/polycarbonate GH.
Polycarbonate IS expensive, but is worth it!
I also remember researching the optimum
roof-slope. There is such a one, but I do not
remember the details... Pl do a lot of googling.
The answer is there (somewhere).
I had found that the answer depends on ones
local latitude and when you want to
optimize. The catch is for sunlight to hit
the roof most-like-at-a-right-angle (at say midwinter).
I did select 'my-angle'  and it turned out to be slightly
shallower than the house-roof. I went with it, but my
other better-half, kind of (too late) complained
that "things" are not parallel...

Definitly choose a south facing spot  (for north USA).

<LMAO>
I needed that!  Spring is coming.

C.J.

Start from here  http://www.building-your-green-home.com/roof-slope.html

Here are some more of the many GH helpful sites:

Solar Greenhouse Resources
http://attra.ncat.org/attra-pub/solar-gh.html

University of Oregon Solar Radiation Monitoring Laboratory Web page.
http://solardat.uoregon.edu/SunChartProgram.html

Hobby Greenhouse Construction
http://www.aces.edu/pubs/docs/A/ANR-1105/

Also think big ... a 16x8' GH is better than 16x6' one.
My (small) ~10x6' GH gets easy very-over-crowded (even with small plants).
Your [south facing] concrete background wall should be a very good heat-buffer (a plus!).
I would not do any concrete floor - maybe just a path using some paving...

Also think of any:
Location 'construction' constraints
Additional night winter-heat
Winter-sunny-day cooling (I originally under-estimated it!)
Entry (door)
Benches/shelves/etc...
[remember most raw material tends to come in 2-foot increments]

Good luck; it was both fun and useful for me.
Beside my nightly-bed, [and dining table...]; my GH is one-best-spot in the house. 

Hi, it seems that for my clear, dry New Mexico climate, 23 degrees is an acceptable pitch for a greenhouse. Thanks for all the advice!