Thursday, September 12, 2013

DIY Greenhouse

Greenhouse made from 2x4s and cattle panel.

This is a Cattle Panel Greenhouse. We have two. One was covered with Clear Plastic and is used as a green house. The other was covered with tarps and is used as a house for our chickens.
While this project wasn’t that difficult or complicated, it was created without any plans or measurements. You should be familiar with your tools and able to adjust as you work.
Tools needed
  • Circular Saw
  • BandSaw or Table saw. An alternative it purchase 2x2s or have some rip-cut 2x4s in half for you.
  • Drill with pilot hole bit and screwdriver bit.
  • Utility knife
  • T-50 Stapler
  • 2 cattle or combo panels. These are 4 feet 4 inches by a little more than 16 feet. These can be purchased at places like Tractor Supply Co.
  • 2 12 foot 2x4s
  • 8 or more 10 foot 2x4s (you will have some left overs)
  • Box of screws 2 1/2 inch power drive screws.
  • Box of nails 16d common sinker or deck nails (something big enough to hold the cattle panel to the 2x4s).
Bend the cattle panels to shape by tying rope to one end and looping it through the other. Then pull the rope so that it draws the two ends together. Have someone help turn the cattle panels until they are standing up correctly. Then continue to tighten the rope until the cattle panels are the right height. Make sure you have room to stand under the middle with about 4 inches extra (there will be a 2×4 holding up the middle).
The two long 2×4 (12 foot) are for the sides. They stick out in the front, to be used as handles, and in back as runners. You can then lift the front (with a helper) to move it around. Cut two boards for the front and back. They should be 3 1/2 inches less than width of the green house (measure how far apart the sides of the cattle panel are and subtract 3 1/2).
The front and rear boards on mine are 7 feet 3 inches or 87 inches.
The cattle panels are 4 feet 4 inches. So attach the front board 2 feet from one end. Drive power screws through the sides into front board.

Tighten the ropes until the cattle panels touch the wood base.

Use nails to anchor the cattle panel to the base. Drive the nails into the base below the cattle panel, then bend them over.

Rear brace
In order to figure out how to cut the angles on the rear brace, which goes from the corners of the base up to the center of the top, I laid two boards down on top of a third. I moved them around until they were wide enough at the bottom and their tops crossed at the right height. Once they were laying correct, I marked the boards at the top and bottom.

Formula in column A are entered into column B|This shows a quick spread sheet to give you the angles for the top and bottom of the brace. At the dimensions I used (87 inch base and 71 1/2 inches from base to the top, the angles are nearly 300 and 600, so you could use standard 300-600 triangle.
180px-hoophouse-calculation.jpgSpread sheet with Calculations

Rear brace installed. You can see the cross piece at the top and the pieces at the bottom. To get the angles, I just put the pieces in place and drew lines. Notice that there will be a 2×4 at the top, so make sure that the top piece is low enough to accommodate it (3 1/2 inches).

The door opening was made from a 2×4 cut in half so that it was 1 1/2 inches by 1 3/4 inches. Notice that the top of the door sits on top of the sides.
I decided how wide I wanted the door, then figured out how tall the side pieces had to be to hold the top that high.
In my case, I wanted a 2 foot 8 inch door. So the top piece was 3 feet. The sides are 5 feet 4 1/2 inches. Build and install the door frame before building the door. The door should be 1/4 inch shorter in both directions than the door opening.
There is a piece on top of the door frame that supports the top 2×4.
Door brace detail. You can use a drafting 600-300 triangle to mark the angles on the front braces. Cut the bottom angle, then hold the brace in place to figure out the length, then use the triangle to mark the correct angle. Screw through the door frame, into the brace at the top. At the base, attach in a similar manner to the rear brace.
Top angle180px-hoophouse-top-angle.JPGBottom angle180px-hoophouse-bottom-angle.JPG
Note the wood L at the base of the door frame. It attaches the door frame to the base.
A 2×4 was installed at the top. It goes over the door and connects with the rear brace. The cattle panels were anchored to the top 2×4 with nails.

Cover with plastic. I covered it with 4mil clear plastic. It lasted about a year. The constant sun makes the plastic brittle. Apparently, there is a “Green house” plastic. I’ll try that next time I have to re-cover it.
The 2nd time I covered the greenhouse, I discovered that by covering the “triangles” on the front, near the door and the big section of the rear with separate pieces of plastic, it is much easier to anchor the top piece of plastic, without excessive gaps and folding.
The plastic is stapled down with strips of cardboard. I used the longest T-50 staples I could find.
The Door is a simple lap joint frame with an old storm window