Greenhouse Project
Made from Old Windows and Doors
- Planning Stages
- Step 1 - Digging the Footers
- Step 2 - Constructing the Floor
- Step 3 - Framing the Walls
- Step 4 - Hardware for Rafters and Interior Supports
- Step 5 - Rafters
- Step 6 - Roof
- Step 7 - Plywood on Walls and Hanging Doors
- Step 8 - Installing Windows
- Step 9 - Framing the Peak
- Step 10 - Soffit
- Step 11 - Trim and Siding
- Step 12 - Counters and Shelving
- Step 13 - Finished with Vegetable Garden

In Spring 2008, we began the planning stages of a greenhouse made from old windows. I had been casually saving windows for a while and mentioned to Gary how it would be neat to turn them into something, maybe a greenhouse. He really didn't comment too much on the idea until one day I realized he had been bringing windows home without my knowledge.
We talked about it and decided we had enough windows collected to start the design work. At that time, we had 21 windows and three doors to work with. There were several different sizes which made designing a little more challenging. I didn't want it to look all pieced together. I wanted it to look like it was meant to be put together.
To the left is a preliminary design for the greenhouse (click on the image to see it in full size). The shaded areas are spaces we need to fill, either with windows, wood or some other material.
I really wanted a cottage style greenhouse, so had already planned to use some sort of wood or siding on the bottom 42" of each side. This will be equal to the height of the wood on the entrance door which is in a Craftsman style. Gary found two solid glass doors that we will use on the back side of the greenhouse and they will open outward if needed.
The greenhouse right now is approximately 12' x 8'. We will use a clear polycarbonate for the roof and the floor will be plywood, similar to a basic shed construction.
Once the greenhouse is built, I will have lots of pathways to construct that will lead you in and around the yard and gardens.
As with any project, the drawing was redone several times. Here is a revised drawing using an 8' x 12' footprint. In doing so, the original wall height of 9' was just too high, so we are reducing it to 7'. We have also determined that the height of the center of the roof will be 3' and will over hang about 1' on either side. I have attached a new layout drawing to the left. Click on the drawing to see it in full size (drawing not to scale).
Gary was finally able to start the greenhouse on Labor Day weekend of 2009.
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| In the photo above he was digging holes for the cement block that were being used to level the building. The holes were filled with gravel and patio base and packed in and leveled. You will notice that some stones are flat and some are cement blocks. We are just using what we have on hand. You won't see them anyway, so there is no need to buy matching blocks or matching filler. We got lucky when we ran low on gravel and found some patio base marked down at Lowes because the bags were broken. Back to Top |
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Gary finished the floor the second week of September 2009. The studs are 16" on center. A little closer than normal to add strength since the wall studs will be spaced a little unconventionally. We used a combination of 4x4s and 2x4s because that is what we had on hand. To the right is a close-up of one of the corners. Gary used a scrap piece of 4x4 to make a corner support. You can also see some chicken wire in this photo. We've had problems with skunks, woodchucks and rabbits digging under our sheds, so we are preventing this problem ahead of time by putting down some chicken wire all around the building. The chicken wire has been stapled to the studs on the inside for extra protection. Since these types of critters like to dig right up against the foundation of a building, they won't be able to since
it's surrounded by the chicken wire. Even if they decide to back up and try to dig some more, they can't because the chicken wire goes out at least 14" on all sides.
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| We finished the floor with three sheets of 4x8 treated plywood. Traditionally a greenhouse floor should be gravel or concrete, but since this will not be used in the winter, I wanted a floor that would be more comfortable to stand on for hobby purposes. The plywood was screwed down on each corner and all down the center of the plywood attaching it to all the studs. There is no need to screw down the outside of the plywood any more than that since the sill plate will be going around the outside, further securing the plywood to the floor studs. Back to Top |
The wall studs are up and we are ready to frame with windows and put up the rafters. The studs are double studs meaning two 2x4s have been attached together at each point to give added strength. The studs are the same distance apart as the windows we are using. The bottom half of the greenhouse will be covered with cedar clap board and insulated and the windows will be on the top half. Gary said that the pieces all fit together like a glove, which I guess is a compliment to me since I cut them all myself. |
The photo to the right shows the framing where the single door will go, which is the front of the greenhouse.Back to Top |
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To the left is a close-up of the hardware we used for the rafters.
For the most part, the majority of this hardware was salvaged from job sites (you'd be amazed at what gets thrown away), and gotten for next to nothing on clearance at a building supply store. When companies stop carrying one brand and start selling another, they mark down many items for pennies on the dollar. Sometimes they even throw them out or give them to their best customers. It helps to have a contact at a store like this. Below is the hardware used for the interior supports of the greenhouse. To help strengthen the frame we screwed together two 2x4s and attached them across the center of the greenhouse at the same point as the wall studs. We connected those with a shorter length of board to create an "H" inside the frame. Remember, since we are using old windows for the walls, the framing is a little unconventional, so we need to compensate in other areas to make sure the structure is sturdy. We attached them with three metal braces (one on each side and bottom) and used a mending plate on the top to prevent this "beam" from becoming separated from the wall stud (sorry, I couldn't get a picture of that part). |
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| I couldn't get a good picture of the additional bracing Gary added, but if you look to the right of the picture below, you will see a wooden brace going from one of the new center supports diagonally up to the top of the rafter. There is one on each side of the greenhouse. This support was constructed by screwing together three 2x4s. At the top of the support, one 2x4 is attached to either side of the rafter. The center piece is cut shorter so as not to interfere with attaching the support to the rafter beam. This support is designed to prevent the building from twisting in heavy winds. Back to Top |
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