The most successful modern greenhouses are built upon well-drained land near a good water supply. Some of the smaller structures are 12 to 15 feet wide, with a framework of wood. For commercial purposes, greenhouses about 40 feet in width, supported by semi-iron or pipe-post frames are found most practical.
The first and foremost consideration in picking a spot for your greenhouse is the position of the winter sun. Tall trees that block the rays of the sun should not surround the site.
Make the base using h4-sawn timber between 2.4 m and 3 m in length. Use galvanized nails and nail plates to join the timber strips to make an oblong. Do not forget to check if the base is level. Once this is done, reinforce the base with pegs around its perimeter. Construct the frame using h3-sawn timber. These timber strips shouldn? T be more than 4.8 m in length. Construct two sidewalls, make the diagonal measurements equal and if the walls are square, cut and fix the bracing timbers in place.
Cut the roof frame pieces using h-3 sawn timber. Then cut 5 rafters, each of 1.9 m, 5 rafters, each of 1.31m, 5 uprights 0.5m in length and 5 triangular gussets measuring 0.5mx 0.5mx 0.5m using 7 mm plywood.
Construct the five rood frames on the ground. Pick two points 2.4 m apart and nail the triangular gussets. Attach the 5 roof frames to the sidewalls. Reinforce with two vertical end roof frames plumb. Then nail the fascia board (150 mm x 50 mm, made out of h3-sawn timber) to the top of the roof frames. Fix the window support plate (75 mm x 50 mm) next and brace the roof on the side that has no windows. Next, work on the windows. Use 50 x 50 h3-sawn timber for the top and bottom frames and 75 x 50 h3-sawn timber for the side and middle. Bevel cut the bottom window frame 30 degrees, which is the same pitch as the roof. Add a latch. Make two such windows and fix them.
You'll need to build two doors using 50 x 50 h3-sawn timber for the frames. Cut the gussets from 7 mm plywood. Check if frames are square before nailing the gussets. Attach the doors using hinges. The cover should be made with ultra- violet resistant polythene using thin battens over the polythene to hold it.