I have been working on this greenhouse for Emily Sean and Noah my wife’s daughter and her family for the last couple of days I have been taking pics. of each step. Here are a few of them.
Grass, kinda level and flat. 12" drop front to back. note the two beautiful redwood trees at the back of the greenhouse area
Stubs pounded into the ground. These stubs are a foot taller than my typical stubs. These allow for a house that is a foot taller than usual. 8'6" instead of 7'6"
Bow set, set into top of stubs. Not bolted in yet.
Knee brace and purlin attachments
These plywood panels have been ripped down to 36″ for a 10′wide greenhouse. Use the 4′ wide panel for a 12′ wide house,
Sawzall the excess material off of the plywood from inside of the house.
Note the third run of 2x4s about 32″ above the ground. This is the bench rail. We will attach the benches to these.
Display House 10'x10'
Above is a greenhouse I used for a display at the Portland Home and Garden show last year. This is what the end wall should look like before you put the transom piece above the door. The opening in the center for the door should be 49″ wide so that you can put a full sheet of plywood in for the door and still have some room on the sides of the door.The plywood is sitting on top of the end wall footer. I happened to build this house inside of a 20′ wide house so I could keep dry.
Here is another example with the transom in place. Note the 2x4s along the sides of the door frame. I usually build them a little different. I will turn those flat 2x4s on edge and not use a separate frame as shown here. My frame is incorporated into the door itself. I will usually measure the opening of the door opening after installing the transom board. The width will be 49″ to fit the 48″ door and whatever the height of your opening is less about an inch and a half. So the door ends up one inch narrower and one and a half inch shorter than your rough opening. When you install the door set it on a piece of scrap 1/2″ plywood that is sitting on the end wall footer 2×4. After you attach the hinges remove the scrap plywood and you will have a half inch of gap at the bottom of the door. This leaves room for some sag. There is also an inch of open air above the door. I will sometimes staple a strip of plastic over that opening, that way the greenhouse can still breathe but the cold air won’t blast in above the door.
I don’t believe in a very tight greenhouse. I think it leads to more moisture problems that can help cause diseases among your plants. As stated before you should have at least one fan and preferably 2 running all of the time in a heated greenhouse that you are growing in.
Below is how I attach my doors. Note that this greenhouse has a foundation frame that allows me to use sand bags to keep the house in place because it’s sitting on asphalt.
One more pic below to show you the base of the greenhouse not attached to the ground. This was a display house that sat alongside Interstate 5 in Washington for several months. This is the method I suggest to folks that are using their greenhouse for a chicken tractor.
More on greenhouse building tomorrow. If you have questions please ask. PLEASE