Introduction: Casa Verde: a Modular Greenhouse

Casa Verde is the result of a school assignment. We worked on this project with 4 students Industrial Design from the University Ghent/ Howest Kortrijk (Belgium).
We were working on different 'Urban Gardening' projects and our assignment was to make a modular greenhouse.
Although we ourselves are not gardeners, we worked in cooperation with an Urban Gardening project, providing us with vital information for the success of our product and we believe that this project could prove useful for a lot of people.

It being a school project realized in a two week span, it means this is a concept that has not been tested, so as of yet we can not guarantee this will work. It would therefore be very appreciated if someone out there would want to test this and let us all know how it worked out.

For now, let's be positive and assume this greenhouse will in fact work. We believe it would.

Casa Verde is unique in ways that it

- is very modular: One module can be used to make all kinds of shapes depending on the surface and height you need to cover.

- gives a visual added value to your garden: Unlike a lot of other DIY greenhouses, this greenhouse looks really good and you definitely will not want to hide it in the back of your garden.

- is durable: It is made out of firm plastic that holds its shape and is weather resistant.

- is stowable: The whole construction can easily be folded to take in very little space once stored in the winter months.

- is affordable: It is not the cheapest greenhouse possible to make, but seen its durability and innovation, it is very good value. For about €50 we covered almost 1,2 m².

And the best of all, you can easily make this. You don't need to be an engineer to be able to make this and almost everybody has the needed tools at home.


Step 1: Materials and Dimensions

We constructed our greenhouse with triangles of 56x56 cm. We chose these dimensions because our client asked for a greenhouse fitting in a 1,20 m grid and because it is a good working standard. We suggest to use these measurements because it provides plenty of space to work on the plants and this makes for a good grid to plant herbs and vegetables at regular distances. These measurements come from a well know method called 'square foot gardening'.

Of course, you are free to tweak this greenhouse to your own liking and change the measurements to fit the plants you want to grow. Maybe you could even change the material and scale everything up to make this into a children playhouse.

The material list is for a greenhouse with 56 x 56 cm triangles, but the graphic above and the letters between brackets will help you to rescale the dimensions. However, you don't need to follow these dimensions very strictly, it is more like a guideline.


- cutter
- hole punch
- handdrill
- ruler
- protractor
- pencil


- sheets of 2.5mm Polystyrene (or another transparant, outdoor purpose plastic like PVC, HDPE, PMMA)
To make 12 triangles with sides of 56cm (A) you need a sheet of 1m x 2m.

- 1mm PVC sheet (or another flexible, outdoor purpose plastic)
You need 6 rectangles of 12,5cm (B) x 8cm (c) per triangle.

- 24 cm cable ties (6 per triangle)
If you don't like the look of cable ties, you can also opt for rivets.

- 58 cm (A+2cm) wooden poles (about 2 per triangle)
Some longer poles can be useful to pin in the ground.

to cover 0.36m² you need 4 triangles
0.72m² you need 8 triangles
1.42m² you need 16 triangles

Step 2: Cutting the Triangles

The first step is to make the triangles out of the sheets of (PS) plastic. To do this, you will need a pencil, ruler,protractor and a cutter.

1. Draw equilateral triangles with sides of 56 cm on the 2.5 mm plastic sheet.
Be accurate. Inaccurate triangles will make for a rickety construction.
Before you start, try to find the best configuration for the triangles to get the most out of your sheets.

Note: Even though we are making a greenhouse fitting a 1.2m x1.2m grid, we don't make the sides 60cm. This is because loops will later be attached so we need a margin to make it fit.

2. Make incisions on the drawn lines with a cutter.
Make the incisions deep enough, especially at the ends, otherwise you won't have a clean break.

3. Carefully break the sheet on the lines

4. Repeat until you have your desired amount of triangles.

Consideration: For our greenhouse we chose Polystyrene for several reasons. It is relatively inexpensive and very easy to work with. It is still strong and can be found with UV-resistance. However, PS is brittle and not as weather resistant as some other plastics. If you want the best quality and you have the money to spend, you can consider using PMMA instead. This material, however can not be cut as easily as PS so you will need access to a fab-lab and use a laser cutter to make the triangles.

Step 3: Making Holes

The holes will be used to attach the connection loops later on. So to make sure everything fits well together, the holes have to be accurate.

1. Marque the places of the holes onto the triangle following the pattern on the drawing above. You need a 3 cm margin at both ends of a side and the remaining space has to be divided in 4 equal lengths. In space 2 and 4 you draw 2 points at a distance of 10cm (B-2cm) of each other and 1,5 cm from the edge. You do the same for the two remaining sides of the triangle.

2. Drill holes with a diameter of 5mm.

Step 4: Making Connection Loops

The loops will make the connection between multiple triangles possible. We made these out of a 1mm thick PVC plastic, which had just the right amount of flexibility. However, if you have a plastic sheet that has a bit more flexibility, it would also work. And with a bit of creativity and tweaking, other materials would be possible as well.

1. With a cutter, cut out rectangles of 12,5 cm (B) x 8 cm. You will need 6 of these rectangles per triangle you make.

2. Marque the places for the holes like you see on the drawing above. The distance between the holes has to be the same as the distance used for the triangles. Distance D on the picture depends on the poles you use. If the holes of the rectangle and triangle are aligned, you need to make sure the pole has comfortable space to slide through the loop.
You can make one template and use it for all the rectangles

3. Make the holes using a pinch hole. If this should not work, you can always drill the holes.

Step 5: Fastening the Loops

We used cable ties to fasten everything because it is a very cheap solution that serves its purpose and we think it looks good as well. If you use coloured ties it can give a nice accent to your greenhouse.

Note: If you don't like the look of cable ties and you have a bit more to splurge, you can opt for rivets instead. The same hole marks from step 3 can be used.

1. Loop the rectangles around the triangles and align the holes. Thread the tie trough the holes and tighten. Repeat this for all the loops.

2. Cut of the excess material of the ties.

3. Make sure the connection of the cable ties is always on the same side so when you make your greenhouse construction, all the connections are on the inside of the greenhouse.

Step 6: Alter the Poles

The poles will fasten the connection between two triangles. It is not so important what kind of poles you use, but we used wooden poles with a 8 mm diameter. If you use thinner or thicker poles, be sure to alter the connection loops so the poles can still slide through.

1. Saw the poles at a length of 58 cm (A+2cm)

2. Give one end of the pole a point using a cutter or a sanding belt if you have one at hand. This will make it easier to slide the pole through the holes.

3. To fasten the greenhouse in the ground, you can make a few longer poles and use these at the bottom row of the greenhouse.

Step 7: Build Your Greenhouse

Now all the pieces are ready so you can start to build your greenhouse. Depending on how many triangles you have, you can make many different constructions.

1. Connect two triangles and slide the pole through the loops. That's it, it is really that simple.

2. To open your greenhouse for ventilation or to work on your plants, just remove one pole and swing a triangle open like a window.

To show you how easy it is to build, use and disassemble the construction, we made a little video.

Step 8: Possible Constructions

If you make enough triangles, it is possible to make a lot of shapes. You can be as creative as you wish, but to help you on the way, we made some scale models, showing the folded and unfolded version.

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