Greenhouse Angle Calculator
Calculate roof pitch slope (degrees & rise:run ratio), rafter length, Gothic arch curve radius, and snow load shedding angles.
Solar Geometry: Greenhouse Roof Pitch & Arch Angle Calculator
The tilt angle of a greenhouse roof determines two critical performance factors: how much low-angle winter sunlight passes through the glazing versus reflecting away, and how easily snow and condensation slide off the roof surfaces. Using our greenhouse angle calculator, greenhouse arch calculator, and greenhouse roof pitch calculator, you can design rafters and arches optimized for your regional solar angle and winter weather load.
Optimal Winter Roof Pitch Rule
To maximize winter solar gain when the sun rests low on the southern horizon, orient roof slopes perpendicular to midday winter rays. The optimal winter roof angle formula is:
Optimal Roof Tilt (Degrees) = Your Geographic Latitude + 15°
For example, at 42°N latitude, an optimal solar roof slope is $42 + 15 = \mathbf{57^\circ}$ relative to horizontal.
Snow Shedding Minimum Thresholds
To prevent structural collapse under heavy wet snow, maintain a minimum roof slope of 28° (6:12 pitch ratio) for smooth poly or glass, and 35° (8.5:12 pitch) for corrugated polycarbonate.