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.

See the panels tested

Polycarbonate is a thermoplastic, so a panel flexes and absorbs impact energy instead of shattering the way glass does. The short test below shows that difference on twin-wall and clear sheets.

Panel resilience test Twin-wall and clear panels

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 types across our range Ratings are per complete structure, not per panel
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.

Choose clear walls if
You want to see in and out

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 range
Choose twin-wall if
You want to grow longer and hotter

You 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 range
Not sure yet
Answer a few questions

Our 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.

Unbranded polycarbonate panel showing yellowing and clouding after two years of outdoor use
An unbranded panel with no UV protection, after two years outdoors.
Palram-Canopia UV protected polycarbonate panel still clear after two years of outdoor use
A Palram-Canopia panel with UV protection, after the same two years.
Comparison of a deformed unbranded polycarbonate panel against a flat Palram-Canopia panel
Deformed edges and an uneven surface on an unbranded panel, next to a Palram-Canopia panel.

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.

Work out your snow load How much does snow weigh?

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

Next step

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.

6 ft. wide 8 ft. wide 10 ft. wide 12 ft. wide
Compare every model Foundation guide
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.