An Amazing Greenhouse From Old Windows

Greenhouse From Old Window

Recycled crafts are some of the most popular projects we have here and we like them all. In addition to their positive environmental contribution, trash-to-treasure crafts are especially frugal, coming with little or no additional cost at all.

These unique trash-to-treasure crafts are great ways to take things that are old and make them new. Our consumerist society throws a lot of supposedly old things out. That’s where creative DIYers step in.

Every day of every week, someone is busy replacing their ‘old’ timber framed windows with ‘whiz-bang, no maintenance’ windows. And every day, thousands of glasshouse kits are sold. DIYer, Chef, made the connection and built a glasshouse from other people’s trash.

Greenhouse from Old Windows

This greenhouse project is one of the most inexpensive builds we’ve come across. Although building a greenhouse from scratch is cheaper than buying a quality new kit, you’re still up for the material expenses such as timber for all the framing plus the cost of the glass. The builder of this greenhouse found a way around this issue by using salvaged windows.

As you can see, the frames and glass in these salvaged windows make perfect building blocks for a greenhouse. You just need to build the frame on which the windows will be installed. You’ll spend very little, if anything, on the windows, depending on where you source them.

Craigslist and Gumtree are great sources for items like this. You’ll also find lots of timber there so all you have to buy are your screws, caulking, and latches.

Click on any image to start the lightbox display. Use your Esc key to close the lightbox. 8-)

You’ll need these materials to make this greenhouse from old windows:

  • Salvaged Windows
  • 4×4 Timber
  • 2×4 Timber
  • Gravel
  • Cinder Blocks
  • Screws
  • Paint
  • Corrugated Sheets

And these tools:


Look for old windows and save everyone you get. After you have many, lay them out and play a game trying to make two pairs of “walls” both the same height. Two to three inches won’t matter as you can cover the difference with wood.

Smaller holes will need to have glass cut for them or filled with something else. Keep in mind that one end will need a door and the other a hole for a fan.


Using the windows you chose as a guide, construct a frame for each wall. Use good lumber for this, as it is the structure that holds all the weight. I used all 2 x 4s for the studs and 4 x 4s for the corner posts. Choose a length that allows at least 14″ of the stud to be placed in the ground for support.


Start placing the walls up, bracing well so they don’t fall over. Be sure to check that they are level.


To avoid certain problems with pesky city building permits, I built the structure shed height and did not pour a concrete foundation. Instead, I buried cinder blocks to stabilize the 4 x 4 corner posts. They keep it from moving an inch.


I used some nice coated deck screws to affix the windows to the frame. This will allow for easy removal and replacement of any break. This side facing the camera has an empty window for a fan.


I was able to find someone who needed rocks removed from their yard. Using rocks or stones is good for two reasons: good drainage and heat storage.


This was tricky. I ended up getting siding from an old shed someone had torn down. For any material you use, look for lightweight and waterproof material. Be sure that you have some that will open for ventilation, at least 20-30% of your floor space.

You can get by with less if you use a fan for ventilation. Also, build the slanted roof with at least a 4-degree pitch, otherwise, rain may not sheet off well.


I found an old picnic bench table and this fan and shelf in the garbage. I figured I can use them in my greenhouse and save them from a landfill.


Use a good outdoor caulk and seal all the cracks and holes between windows. Paint the wood to protect it from the weather.


I was unhappy with having to remove the fan/vent window and having to prop it against something while cooling the greenhouse during the day. The frame was already designed to fit the window into it. I decided to have it slide up and be held in place.


I started by salvaging some hinges from an old entertainment centre. They are the kind that sits completely outside the door. Plus these had a unique shape that fits around a right angle. This allowed the wooden “stops” to swing in place and hold the window up while I was venting or when the fan is in place.


Across the frame, I nailed some boards to hold the fan window against the frame. Lastly, I found an old pulley and fastened it to the window so I can pull it up easily.


A local community greenhouse was torn down and replaced. I was able to get some great parts. Here is a picture of the new window system. It originally opened the windows on the side of the greenhouse. The wheel is turned and rotates the gear attached to the pipe opening the windows. Makes opening and shutting easy. While every window now must be open at the same time, I can control the angle at which they are open.


Also pictured is a gutter claimed from the trash. The hinge side of the roof windows always leaked profusely. The gutter catches the water and stores it in a bucket for easy watering.


Spring Shading. Bought secondhand some rolling shades which are working great. They easily roll up and down the south-facing wall while not taking up too much room.


Here is the greenhouse in a mild winter.  I overwinter many potted perennials inside. To insulate the roof, I stretch a sheet of poly across the top to keep out the drafts.


All the wood is doing well. I hope that, with care, the greenhouse will last over 10 years. It has changed the way I garden, making my backyard much more productive.

Could this be the project for improving your garden? 🙂

Thanks to cheft for this great project.



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