Polycarbonate Greenhouse Panels
Is polycarbonate the right choice for a Canadian greenhouse?
For almost every Canadian backyard, yes. Polycarbonate is a tough, glass-like polymer. It lets light through like glass, but it does not shatter, which matters when your greenhouse has to face hail in July and a snow load in February.
The real question is not glass versus polycarbonate. It is which polycarbonate panel you should buy, because the panel decides how much light gets in, how much heat stays in, and what the structure is rated to carry. This page explains the four panel types we sell, what each one is for, and how to pick.
The short version. Clear 0.7 mm walls give you the best view and the most light. Twin-wall panels trade the view for insulation and diffused light that will not scorch seedlings. The thicker twin-wall models are the ones rated to 100 kg/m² of snow.
The four panel types, and what each one is for
Every greenhouse we sell uses one or more of these. The ratings below come from the same specification data as our individual product pages, so the two always agree.
| Panel | What it does | Used on | Rated snow load | Rated wind |
|---|---|---|---|---|
|
0.7 mm clear single layer, walls |
Maximum light and a clear view straight through. Used on walls, paired with a twin-wall roof. | Hybrid, Victory Orangery, Americana | 75 kg/m² 15.4 lbs/ft² |
90 km/h |
|
4 mm twin-wall two layers, roof |
Diffused light and an insulating air gap. The standard roof panel across most of the range. | Hybrid, Victory, Americana, EcoGrow, Grand Gardener, Prestige | 75 kg/m² 15.4 lbs/ft² |
90 km/h |
| 6 mm twin-wall | More insulation than 4 mm, still diffused. Used on Rion walls, and throughout on Bella. | EcoGrow, Grand Gardener, Prestige (walls); Bella (throughout) | 75 to 100 kg/m² 15.4 to 20.5 lbs/ft² |
90 to 100 km/h |
| 10 mm twin-wall | Our thickest panel, roof and walls. Most insulation, most diffusion, least see-through. | Glory | 100 kg/m² 20.5 lbs/ft² |
100 km/h |
The snow and wind rating belongs to the whole greenhouse, the frame and the glazing together, not to the panel on its own. A thicker panel does not automatically raise the rating. Check the figure on the individual product page for the model you are considering.
Choosing between clear and twin-wall
This is the decision most people are actually making, and it comes down to what you want the greenhouse to do.
You want the greenhouse to look like a garden room, you want maximum light for a short season, and you like watching the plants from the patio.
See the Hybrid rangeYou want to start earlier in spring and push later into autumn, and you would rather have soft, even light than a clear view. Seedlings do not scorch under diffused light.
See the 10 mm Glory rangeOur selector asks what you grow, how much space you have and how much winter you get, then narrows the range down for you.
Which greenhouse should I buy?Why the UV layer is the part you cannot see
All the panels we sell carry UV protection on the outer face. It shields the panel itself from the sun, and it shields your plants from the harshest of the UV coming through.
You cannot tell whether a panel has it by looking. A new sheet without UV protection looks just as clear and feels just as solid. The difference only shows up after a couple of Canadian summers, and by then the panel is on your roof.
This is where a cheaper greenhouse gets expensive. A panel that clouds, yellows or goes brittle has to be replaced, and replacing glazing on a structure whose manufacturer you cannot trace is difficult and often impossible. It is worth reading the parts and warranty terms before you compare two prices.
What the snow and wind ratings actually mean
Every greenhouse on our site carries a rated snow load in kg/m² with the imperial conversion in lbs/ft², and a rated wind speed in km/h. Those are the manufacturer's tested figures for the complete structure.
Snow load is the one that catches Canadians out, because the number that matters is not how deep the snow is. It is how much that snow weighs, and wet or packed snow can weigh several times what the same depth of fresh powder does.
Looking after polycarbonate
- Fit it the right way up. The UV-protected face is marked, and it must face outward. Fitting a panel upside down removes the protection you paid for.
- Clear heavy snow off the roof. Even on a greenhouse rated to 100 kg/m², wet snow accumulating past the rating is the most common cause of damage in Canada. A soft broom from outside is enough.
- Wash with mild soap and water. No solvents, no abrasive pads and no pressure washer. Polycarbonate scratches more easily than glass.
- Leave the protective film on until the panel is installed, then take it off. Left in the sun for months it becomes very hard to remove.
The assembly manual for your model gives the panel orientation and the exact fixings, and it is worth reading before you start.
Video
Every greenhouse we sell is a Palram-Canopia or Rion kit, shipped from Mississauga, Ontario. We have been selling them in Canada since 2007. Browse by width, which is the dimension that decides whether you get one bench or two.
Sources and small print
Where the figures come from. The snow load and wind ratings quoted on this page are the manufacturer's tested figures for each complete greenhouse, taken from the same specification data that appears on our individual product pages.
Ratings apply to the whole structure. Frame and glazing are tested together. A thicker panel does not on its own raise the rating, and figures vary by model and size. Always check the product page for the model you are buying.
Snow load is a weight, not a depth. Density varies enormously with moisture and compaction. Use our calculator as a guide only, and clear the roof when snow builds up.
This page is general guidance. It is not an engineering assessment and it does not replace local building requirements. If you need a stamped structural opinion for a permit, speak to a local engineer.
Questions? Call us toll free on 1-877-322-5487 or email sales@canada-greenhouse-kits.ca. We answer the phone ourselves.