Question - I am having a dilemma trying to design windows and roof vents that will be weather proof. Could you offer
Answers - Figure 1 is a drawing from Greenhouses by Ortho depicting a good way to build roof vents. Make
sure you put foam tape at the overlap to seal out air.
For weather-tite greenhouse windows, I took this drawing from Classic Garden Structures by Jan & Michael Gertley.
The Sill (E) is tapered so the water runs off. Caulk around BJ and BI and put foam tape between the window and the stops. The window is hinged from the outside on the top rail.
Both these books are very inexpensive and highly recommended. Click on the links (or pictures above) to purchase them from Amazon.com