Building your own garden “retractable solarium” (basically a mobile glass house or low canopy) is a brilliant way to extend your sunbathing season from early spring to late autumn. It works on the principle of the greenhouse effect – it’s pleasantly warm inside, even if a cold wind is still blowing outside.
Here’s a simplified guide on how to build a low, retractable solarium that even a skilled beginner can handle.
🛠️ What is a retractable solarium?
It’s a low structure (approx. 60–80 cm high) with a transparent filling that is placed on rails. When you want to sunbathe in the lee, you’re under it. When it’s hot or you want to go outside, simply slide the top part away.
Required materials:
Construction: Aluminum profiles or light wooden prisms (treated against moisture).
Filling: Cellular polycarbonate (4–6 mm thick) – it is light and filters aggressive UV radiation (but lets heat through).
Movement system: Small rubber wheels and aluminum guide rails (U-profiles).
Base: Wooden terrace or concrete slab.
📋 Detailed procedure
- Preparing the base
The solarium must stand on a solid and flat surface. A wooden terrace (decking) is ideal. It should be at least 220 cm long (so that you can stretch out comfortably) and about 100–120 cm wide. - “Cart” frame
Build a rectangular frame from light profiles.
Create an arched or gabled roof (an arch is better for rainwater drainage and the strength of polycarbonate).
The height should be such that you can comfortably read a book inside, but not too high so that the air inside heats up quickly.
- Installing polycarbonate
Fasten the polycarbonate sheets to the frame using screws with a sealing washer.
Important: The polycarbonate cavities must be sealed with tape to prevent algae and condensation from forming in them.
- Installing the rails
Mount two parallel rails on the floor. Attach the wheels to the bottom of the solarium frame. The entire object should be able to be moved with one finger.
🌡️ Safety and comfort (Critical points)
To avoid boiling inside like in a greenhouse, you need to think about the details:
Ventilation: Make openings at both ends (at the head and feet) or leave a gap for air to circulate. Without this, you risk overheating your body!
UV protection: Be careful, regular polycarbonate has a UV filter on the outside. This means that it will protect you from burning, but you will not get a tan. If you want to really get a tan under it, you need to use special UV-permeable plates or make part of the canopy openable.
Anchoring: The solarium is very light and the wind could blow it away to the neighbors. Always install a safety lock (hook) to secure it to the floor when not in use.
💰 Advantages of building your own
Property Homemade Purchased covering
Price approx. €150 – €300 from €1,500 upwards
Dimensions Exactly to the size of your terrace Standardized
Repair You can repair it yourself for a few euros Manufacturer’s service required
Why build it at all?
A retractable solarium will allow you to catch a tan already in March, when it is, for example, only 10 °C outside. Under polycarbonate, the temperature in sunny weather rises to a pleasant 25–30 °C within a few minutes.
Would you like me to draw up an exact list of materials (e.g. how many screws and what area of polycarbonate to buy) for a standard size of 2×1 meter?