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Which multi-skin sheets for greenhouse and cold frame? Tips for selection and installation

Durable and practical – this is how to describe greenhouses made of polycarbonate. In terms of performance characteristics, they surpass similar systems made of film and glass. However, in order for this modern material to show its best qualities, it is important to know what to look for when choosing multi-skin sheets for the greenhouse or cold frame and how to install them properly.

The advantages of polycarbonate sheets

Greenhouse made of polycarbonate plates for tomatoes

Why should you use polycarbonate multi-skin sheets for your greenhouse or cold frame? The answer is: because the material has many positive properties and offers a lot of advantages, such as:

  • excellent thermal insulation
  • high light transmission
  • reliable protection against UV radiation
  • high strength, impact resistance, rigidity and hardness (compared to glass, the strength of polycarbonate is 50 times higher, the impact resistance is 250 times higher)
  • easy installation
  • long durability
  • resistance to high humidity and various atmospheric influences
  • high aesthetics: you must admit that a polycarbonate greenhouse (or cold frame) looks very beautiful, stylish and natural in any garden, and can also perfectly fit into a modern landscape design.

7 Tips for choosing and installing the multi-skin sheets for greenhouse and cold frame.

Clear, tinted or opal greenhouse and cold frame sheets

Whether you want to buy a greenhouse or cold frame made of polycarbonate ready-made or build it yourself, the tips for installing the multi-skin sheets hardly differ. Here are the following special features to consider:

Multi-skin sheets for greenhouse – clear or opal?


Only transparent polycarbonate should be used for a greenhouse or cold frame. Tinted double-glazed sheets look more attractive, of course, but they let in much less light and your plants won’t get enough sun. And that’s crucial for a good harvest.

UV resistance is especially important

When choosing multi-skin sheets for the greenhouse or cold frame, make sure they have a special UV-protective coating on at least one side. When installing the sheets, lay them so that the protective layer is on the outside.

Which panel thickness is best?

Greenhouse for growing tomatoes

The thickness of the polycarbonate panels depends on how exactly you want to use your greenhouse. That is, if you want to use your greenhouse only in the spring and fall (unheated) for raising young plants, a panel thickness of 5 to 10 mm is quite sufficient. 6 mm double-webbed sheets for the cold frame are also an optimal solution. If a greenhouse is to be heated, the thickness of the polycarbonate sheets should not be less than 15 mm.

Pay attention to the direction of laying the multi-skin sheets.

All double-webbed sheets have hollow chambers that run parallel to the length of the sheet. During installation, the multi-skin sheets should always be laid with the chambers in the direction of water flow and not across.

Correct installation of multiwall sheets

Fixing multi-skin sheets with screws and washer

Polycarbonate sheets should be installed with special installation profiles made of aluminum or plastic. Self-tapping screws made of stainless steel are used to fasten the multi-skin sheets. A rubber washer should be installed underneath.

Since the polycarbonate has a high coefficient of thermal expansion, the hole must be slightly larger in diameter than the screw. The fastening should start from the edge of the sheet at a distance of about 5 cm, the distance between the fastening points should not exceed 30 cm.

Never fasten the web panels with nails – this will compromise the integrity of the panel and inevitably lead to its destruction. Also take into account the fact that it is not possible to overlap the plates.

Do not sacrifice important details

Cold frame made of wood and multi-skin sheets for salads

Do not skimp on components that are necessary for proper installation of the multi-skin sheets! Such seemingly insignificant details as adhesive tapes, end profiles and seals will significantly extend the life of your greenhouse and prevent irreversible contamination by dust, algae and insects.

The cheap is expensive

Given the variety of polycarbonate sheets available on the market, you should pay special attention to quality. In many cases, the price is perceived as an indication of quality, so it is best to reach for medium-priced or more expensive multi-skin sheets – they will last much longer.

By the way, the multi-skin sheets are also very popular as terrace roofing. You can learn more about it in this article.

10 mm multi-skin sheets for unheated garden house for growing vegetables optimal