How to build a Greenhouse
1: Introduction, Description, Position
2: Sizes, Angles, What you will need
3: Making the base
4: Making the side wall-frames
5: Making the roof sections
6: Erecting the side walls and roof
7: Making the end walls and doors
8: Making the window, The cover
Appendix 60° and 30° Angle patterns
Appendix Photos of finished project
Step 3. The roof frame sections
Make up five roof sections that span from side-wall to side-wall. Refer to the plans and instructions below.
Cut all roof frame pieces to the dimensions given above.
Use 1 1/2"x 3 1/2" (90mm x 45mm) treated, or natural decay-resistant lumber.
In all, cut 5 long rafters @ 73-3/8" (1835mm), 5 short rafters @ 53-5/8" (1340mm) and 5 rafter uprights @ 11 3/8" (285mm) all with end angle cuts as shown in the plan drawing.
Also cut five triangular gussets (equilateral triangles) from a sheet of 3/8" (10mm) treated plywood, with all three sides being 20" (500mm) long.
On a flat piece of ground, make up the five roof sections to the pattern and dimensions as shown in above drawing. Ensure the two furthest points are 8ft" (2400mm) apart and then nail the triangular gussets in place with galvanized flathead nails spaced every 2" (50mm) apart, one gusset to each roof section.