We see less and less greenhouses covered in polyethylene film or expensive glass greenhouses. Gradually the cellular polycarbonate takes over. The name comes from the internal structure of the material. Two or more layers of transparent sheets are interconnected by a large number of strength ribs (lintels).
This structure provides the polymer material with unique qualities: light and heat transmission, durability, weight, and, essentially, the price. Cellular polycarbonate currently is the most popular material used for covering greenhouses.
In this article we will tell you about the main criteria, which you need to take into account when buying polycarbonate:
1) For covering the greenhouse only 4 mm and 6 mm thick sheets of cellular polycarbonate are used. We do not recommend to use 3.6 mm or 3.8 mm thick polycarbonate. This is a low quality polycarbonate, which will not serve you long.
2) Prior to purchase of polycarbonate you need to determine the number of sheets, which is calculated by use of the total greenhouse length and standard dimensions of the polycarbonate sheet. Standard polycarbonate sheet dimensions: 2.1 x 6 m and 2.1 x 12 m.
3) UV-ray protection. It is important to know that the cellular polycarbonate, as any other polypropylene, is destroyed by the constant exposure to sunrays. UV protection layer must be externally applied. There are retailers who say that the UV protection was added to the “mass”, meaning, that UV protection elements were added to raw materials from which the polycarbonate is made. This is not natural, and such polycarbonate will definitely last less than 2-3 years.
4) Warranty period. The higher the quality of polycarbonate the longer the warranty period it has, and, of course, it cannot be cheap. Quality cellular polycarbonate has warranty period for at least 10 years.
5) Markings LIGHT, ECO, ECONOMY - indicate a lighter polycarbonate, which also costs slightly less. Why so? Example: replace a 4 mm thick sheet with 3.5 mm thick sheet, and the total thickness will be reduced to 0.52-0.6 kg/m2. It also means the reduce period of use.
Benefits of cellular polycarbonate are obvious:
Polycarbonate is 6 times lighter and 200 times more durable than silica glass. Due to these qualities the greenhouse does not require a sturdy foundation. Light transfer of two-ply cellular polycarbonate sheet can reach 88%. The fact that the sunrays that pass through the polycarbonate are disseminated is also important. However, the UV radiation is almost totally prevented by polycarbonate panels. Such lighting prevents sun-burns on plants and positively affects growth. Cellular polycarbonate significantly exceeds polyethylene film in regard to heat insulation and durability. Multi-layer structure allows to retain heat. Polycarbonate sheets retain their qualities in temperatures as low as -40 and as high as +120 degrees Celsius.
