How to Build a 10 By 20 Greenhouse

Measure and cut two 2-foot sections of 2-by-4 from one of the 12-foot studs. These will be used to join the 2-by-6 boards to fashion the 20-foot sides of the greenhouse base. Set the two 2-by-6 boards end to end and join them together by nailing them to the cut 2-foot section of 2 by 4, which should be placed on top so that it overlaps both boards. This will create a 2 by 6 that is 20-feet long for the sides of the greenhouse base frame.

Lay out the 10-by-20 foot greenhouse base frame using the nailed together 20-foot side boards and two 10-foot 2-by-6 boards for the ends. Nail the sides to the ends. To ensure it is the right dimension, measure from one corner diagonally to the opposite corner in both directions in an "X" pattern. To make sure the 10-by-20 foot base frame is square the distance should be 22 feet, 4 inches. If both measurements are the same, the frame is a proper rectangle.

Cut the 10-foot pieces of rebar. Replace the wood cutting saw blade with the diamond saw blade on the circular saw and cut each 10-foot piece of rebar into four 30-inch long pieces, for a total of 24 pieces. Pound each length into the ground on the outside of your frame about 15 inches deep and about half an inch from the frame. Put one piece at each corner, and every two feet along the long sides of the frame. You should have 11 pieces of rebar along each of the long sides of your frame.

Construct the PVC rib structure to create the rounded sides and top of your greenhouse. Slide a piece of PVC pipe onto each of the 11 rebar pieces on one side, and secure the ends with the flexible metal banding. Cut the flexible metal banding into 6-inch sections. Wrap the banding over the PVC pipe and nail each end of the flexible banding to the base frame on either side of each PVC pipe, this will strap the PVC pipe to the base frame. Bend each of the 11 pieces of pipe carefully over to the opposite side of the base frame and slide the free ends onto the rebar, securing it again with the banding. This will create rounded loops of PVC pipe that will be used as the frame ribs to form the side walls and roof of the greenhouse.

The PVC pipe is flexible enough to create rounded loops and will not break as long as they are not bent to to severe of an angle

Attach the last piece of PVC pipe to the center of the PVC loops. Run the PVC pipe along the inner radius of the 11 PVC pipe ribs and the zip tie it to each rib. This will add some rigidity to the structure.

Build the end walls. Using the wood cutting blade, cut a 2-by-4-by-12 down to 9 feet 9 inches, this will form the base of your end wall. Cut two 6-foot long pieces; two 4-foot, 6-inch long pieces; and two 18-inch long pieces. Nail the two 18-inch studs to the top your base board, making sure it is flush with the end. Measure 18 inches in from the center of each 18-inch tall stud and nail the 4-foot 6-inch studs to the top of the 2-by-4 base board. Measure 18-inches in from the center of each 4-foot 6-inch tall stud and nail the 6-foot tall studs to the top of the 2-by-4 base board. Cut four 18 3/4 inch pieces of 2-by-4 and one 43 1/2 inch piece. Nail the 43 1/2 inch piece across the tops of the 6-foot tall studs. Nail one end of an 18 3/4 inch piece of stud to the top of each 4-foot 6-inch tall stud and nail the other end to the 6-foot tall studs, parallel with the ground to form two smaller rectangles one on each side of the doorway frame. Nail one end of an 18 and 3/4 inch piece of 2-by-4 to the top of each 18-inch tall studs and nail the other end to the 4-foot 6-inch tall studs, parallel with the ground to form two smaller squares on each side. The completed frame should look like a stepped pyramid. Set the wall inside the 10-by-20 foot base frame and nail it to the end board. Cut four 28-inch long studs. Cut one end on each 28-inch stud at a 45 degree angle, these will be used a diagonal braces to sturdy the end walls. Nail the 45 degree end at each of the corners where the the 18-inch stud meets the 18 3/4 inch piece, making sure the braces do not protrude past the front face of the walls. Nail the other end to the 2-by-6 boards that form the sides of the 10-by-20 foot base frame. Repeat these steps to build an identical wall for the other end of the greenhouse.

Attach the 20-by-50 foot 6mm plastic sheeting to the the structure. Roll the plastic out lengthwise along one of the long sides. Situate the plastic so that 15 feet of plastic stretches out past each end of the greenhouse.

With help, pull the plastic sheeting over the stop of the PVC ribs and make sure that the 20-foot width of the plastic is centered over the structure. Starting at the center on one of the 20-foot sides of the greenhouse, staple the plastic to the base frame. Work your way to each corner of the frame, attaching the plastic with staples about every 4 inches. Repeat on the opposite side.

Wrap the end walls in plastic sheeting. Pull the plastic taught and staple about every 4 inches along the bottom edge of the frame. Cut off the excess plastic sheet and save for later. Fold over any loose extra plastic caused by the circular shape and staple it to the base board . On the end that the door is going to be mounted on, cut an "X" into the plastic sheeting from corner to corner in the center frame. Wrap the plastic around the edges of the doorway and staple it on the back of the framed wall.

Construct the door. Cut two pieces of 2-by-4 stud to 5 feet 6 1/2 inches long and two pieces 42 inches long. Nail the shorter studs to the longer studs to form a rectangle that is 5 feet 10 inches tall and 42 inches wide. Lay a 2-by-4 diagonally across the door frame from corner to corner and nail it into place to form a cross brace. Cut off the ends that protrude past door's frame.

Cover the door with the extra plastic sheeting. Wrap the plastic around the edges of the door frame and staple the plastic to the backside of the frame. Make sure one face of the door is covered completely with plastic. Attach the two fence hinges to the door with wood screws. Place the hinges 3inches from the top and bottom of the door frame on the left side. Attach the fence handle to the door with two wood screws.

Place the door in the doorway and attach the free ends of the hinges to the wall using wood screws.