Polycarbonate Roof Panels in Canada (2026): Solid, Multiwall and Corrugated

Polycarbonate roof panels cover a lot of ground in one phrase. The same three words describe a clear skylight over a Toronto atrium, an insulated twin-wall roof on a Leamington greenhouse, and a corrugated patio cover on a cottage deck in Muskoka. Those are three different products with three different price tags, and buying the wrong one is the most common mistake we untangle on the phone.

This guide sorts out which polycarbonate roof panel actually fits your project. We stock solid clear polycarbonate sheet at our North York warehouse and supply it across Ontario every week, so the pricing and thickness advice here comes from real orders, not a spec sheet. For the broader material background, our complete polycarbonate buyer's guide for Canada covers the resin itself in full.

Key takeaways:

• Polycarbonate roof panels come in three formats: solid sheet, multiwall (hollow channel), and corrugated profile. They share one resin but perform very differently overhead.
• Solid sheet wins on clarity and impact resistance; multiwall wins on insulation for greenhouses and conservatories; corrugated is the budget choice for pergolas and carports.
• FIDAR System stocks solid clear polycarbonate from 2mm to 9mm. Overhead glazing usually starts at 6mm, which runs $185.41 CAD per 4x8 ft sheet.
• Thickness follows snow load. The National Building Code sets roof load at 0.8 of the local ground snow load, so a panel that works in Windsor may be undersized in Quebec City.
• Every roofing panel needs a co-extruded UV layer facing the sun. Generic sheet with no documentation is the leading cause of failed outdoor installs.

What Are Polycarbonate Roof Panels?

Polycarbonate roof panels are clear or tinted plastic glazing sheets used in place of glass on skylights, canopies, greenhouses, and covered structures. The material is up to 250 times more impact-resistant than glass and about half its weight, so a hailstone or a dropped tool dents the panel instead of shattering it onto whatever is below. That single property is why polycarbonate dominates overhead glazing in Canada.

The confusion starts because "polycarbonate roof panels" is sold in three completely different physical formats, and a homeowner pricing a carport and an architect specifying an atrium are often shown the same search results.

Solid polycarbonate sheet

Solid sheet is a single flat layer of clear polycarbonate, the same material we supply for machine guards and safety glazing. It transmits roughly 88% of light, takes the hardest hit of the three formats, and cold-bends on site for curved canopies. It carries no insulation value beyond the sheet itself, so it suits unheated structures: skylights, glazed walkways, entrance canopies, and curved roof lights. This is the format we stock, from 2mm up to 9mm, and you can see the full range on our solid polycarbonate sheet page.

Multiwall polycarbonate

Multiwall sheet has two or more thin layers connected by internal ribs, leaving hollow air channels that run the length of the panel. Those air gaps are the whole point: they trap a layer of still air the way a double-glazed window does, which is why multiwall is the default roof for a heated greenhouse, a pool enclosure, or a four-season patio room. Light transmission drops to roughly 50% to 80% depending on wall count and tint, and the diffused light it produces is actually a benefit for growing plants. Brands like Palram sell multiwall under names such as Sunlite and Thermoclear.

Corrugated polycarbonate

Corrugated panels are thin profiled sheets pressed into a wavy or trapezoidal shape for rigidity, the plastic cousin of corrugated metal roofing. They are the budget option: lightweight, fast to install on a pergola or carport, and cheap per square foot. Clear corrugated transmits up to about 90% of light, while solar-control versions are made to pass only 20% to 50% to keep heat out of a patio. They carry almost no insulation value and the profile must match the support spacing, so they are an outdoor-cover product, not a glazing-grade one.

One thing to be clear about before you order anywhere: these formats are not interchangeable, and price comparisons across them are meaningless. A square foot of solid 6mm and a square foot of clear corrugated are different products solving different problems.

Solid Polycarbonate and Glazing Sheets at FIDAR

Polycarbonate Solid Clear Sheets

Impact-resistant clear PC — 2mm to 9mm, 4×8 ft

From $82.41 CADView Product →

Single-sided Frosted Polycarbonate Sheets

Frosted / white matte PC — privacy and diffusion in one panel

From $89.41 CADView Product →

Diffused White Polycarbonate Sheets

Even LED diffusion — white PC for backlit signs and light panels

From $89.41 CADView Product →

Cast Clear Acrylic Sheets

Optical-grade clarity, 1mm–25mm thickness

From $37.97 CADView Product →

Solid, Multiwall or Corrugated: Which Roof Panel Do You Need?

Match the format to the job, not to the lowest price. Choose solid sheet when clarity and impact resistance matter and the structure is unheated. Choose multiwall when the space underneath is heated and you need to slow heat loss. Choose corrugated when you want a low-cost outdoor cover and a little light diffusion is acceptable.

In practice the decision is usually obvious once you name the space. A grower near Leamington re-roofing a heated greenhouse needs multiwall, because losing heat through single-layer glazing through an Ontario winter is a fuel bill nobody wants. A cottage owner near Huntsville roofing a lakeside deck wants corrugated or solid, depending on whether the look matters from inside the cottage. A property manager replacing a cracked atrium skylight needs solid sheet, because the architect specified clear glazing and the panel sits over a public lobby where impact resistance is the entire reason glass was ruled out.

Where solid sheet earns its keep is anywhere a panel has to survive a hit and stay optically clear. We see it most on entrance canopies, covered walkways between buildings, and curved barrel-vault roof lights that get cold-bent into a frame on site without any heating equipment. If you are still weighing polycarbonate against acrylic for an overhead application, our acrylic vs. polycarbonate comparison for Canada walks through the trade-offs application by application, and the short version for roofs is simple: acrylic is clearer and harder, but it cracks under impact and gets brittle in deep cold, so polycarbonate wins overhead.

How Much Do Polycarbonate Roof Panels Cost in Canada?

Solid clear polycarbonate runs from $82.41 to $325.41 CAD per 4x8 ft sheet at FIDAR System, depending on thickness. These are our live North York warehouse prices, not estimates, and overhead glazing work almost always lands in the upper half of the range because roofs need 6mm or thicker:

A full 4x8 sheet is 32 square feet, so 6mm overhead glazing works out to about $5.80 per square foot before any cutting. Hold that number against the cut-piece prices a hardware chain charges for the same material and the gap is usually two to three times. If your roof needs more than a couple of small panels, price the full sheet first and plan your cuts, or use our cut-to-size service and keep the offcuts for flashing and trim.

Weight is the other number that decides overhead jobs. Calculated from polycarbonate's 1.20 g/cm density, a 6mm 4x8 sheet runs about 21 kg and a 9mm sheet about 32 kg, which is less than half what the same panel would weigh in glass. That difference is why a two-person crew can lift a polycarbonate roof panel onto a frame that would need mechanical handling for glass, and it lightens the structural load the supporting frame has to carry.

Multiwall and corrugated panels are priced differently. They sell by the profile and the run length rather than by a flat 4x8 sheet, and freight on long panels is a real line item, so those formats are always quoted per project rather than off a price list. Volume pricing on our solid sheet applies from 10 sheets of the same SKU, and commercial roofers and glazing contractors get standing trade pricing once an account is set up.

What Thickness Do You Need for a Polycarbonate Roof in Canada?

For solid overhead glazing in Canada, 6mm is the practical floor and 9mm covers wider spans and heavier snow. Anything thinner belongs on vertical glazing or tight cold-bent curves where the frame carries the load. The reason roofs need more thickness than wall panels is straightforward: a roof carries snow, and Canadian snow loads are unforgiving.

The National Building Code of Canada sets the design roof snow load at 0.8 of the local ground snow load for a typical roof, dropping to 0.6 only for roofs the designer can show stay fully wind-swept. Ground snow loads are set location by location in the Code's Appendix C climatic data, and the spread is enormous: the design ground snow load runs from roughly 1.1 kPa in Calgary to above 4.0 kPa in parts of interior Quebec such as the Saguenay. A panel and frame that pass easily in Windsor or Vancouver can be badly undersized further east, which is why thickness and span have to be matched to your actual location, not a national average. Thickness is only half the equation, because the distance between your purlins or glazing bars matters just as much. A 6mm sheet spanning 600mm behaves very differently from the same sheet spanning a metre.

Overhead polycarbonate glazing has to carry Canadian snow load, which is why roofs start at 6mm.

If you are replacing an existing roof panel, measure it and match it rather than guessing, because old imported sheet does not always match its nominal thickness. If you are designing from scratch and torn between two gauges, take the thicker one. On a typical canopy the step from 6mm to 9mm adds about $140 per sheet, which is small insurance against a deflected panel that ponds water or, worse, fails under a wet spring snow load. The same logic we apply to matching acrylic thickness to span, covered in our sheet sizes and thickness guide, applies to polycarbonate roofs.

Are Polycarbonate Panels Good for Greenhouse Roofs?

Yes, and for most heated greenhouses they are the best choice, but the right format is multiwall rather than solid. A greenhouse roof has to do two jobs at once: pass enough light for the crop and hold heat through cold nights. Multiwall polycarbonate does both because its hollow channels trap air for insulation while the translucent walls scatter incoming light into a soft, even glow that reaches lower leaves better than the harsh direct light through glass.

The insulation gain is measurable. A 6mm twin-wall panel rates around R-1.6 and a 16mm triple-wall panel around R-2.5, and growers commonly report 30% to 50% lower heating costs against single-glazed glass, according to multiwall manufacturer data. Solid sheet carries almost no insulation value on its own, which is why it suits unheated structures and small lean-to roofs rather than a greenhouse you intend to heat through a Canadian winter.

Multiwall polycarbonate diffuses light and traps air, which is why growers favour it for greenhouse roofs.

Format choice for growing structures comes down to how the space is used. A commercial grower heating a greenhouse through an Ontario winter wants twin-wall or triple-wall multiwall, where the extra channels cut heat loss the most. A backyard hobby greenhouse or a lean-to against a heated wall does fine on twin-wall or even solid sheet on a small roof. An unheated hoop house or a season-extension cold frame, where the goal is frost protection rather than growing through January, is the natural home for corrugated panels and their lower cost. For the diffused even light that some indoor growing and signage work wants, we also stock diffused white polycarbonate and single-sided frosted sheet, which solve the light-spreading problem on flat panels rather than roofs.

Whichever format you land on, the UV layer rule is the one that decides whether a greenhouse roof lasts 3 years or 15. The protected side has to face the sky, every panel, every time. Quality sheet carries a co-extruded UV layer bonded into the surface during manufacturing, the same protection the Lexan brand built its name on, and you can read more about why the brand name matters less than the spec in our Lexan polycarbonate guide.

How Do You Install and Cut Polycarbonate Roof Panels?

Polycarbonate roof panels install with ordinary shop and site tools, and three rules prevent almost every failure we hear about. Cut with a circular saw running an 80-tooth carbide blade or a jigsaw with a fine blade, fed at a steady pace so the blade never lingers and remelts the cut. Score-and-snap does not work on polycarbonate; the material is too tough to fracture at a line, which is the whole reason you bought it.

Keep the masking film on through cutting and drilling, and oversize every fastener hole.

The three rules that matter most on a roof:

• Drill oversize and use the right fasteners. Fastener holes need 1 to 2mm of clearance over the bolt, and roof panels need profiled washers or fixing buttons that seal the hole. Polycarbonate moves about 5mm across a 4 ft panel over a Canadian seasonal swing, and a tight hole turns into a crack by February.
• Seal multiwall channels. Open multiwall ends collect water, dust, and insects. Seal the top with solid breathable tape and the bottom with vented tape, then cap both with a U-profile so the channels drain and stay clear.
• Leave an expansion gap and keep the film on. Frame systems need a 3 to 5mm gap at every edge, and the masking film should stay on through cutting and drilling to protect the soft surface and mark the UV side.

Solid sheet adds one bonus skill on a roof: cold bending. A 3mm sheet curves to roughly a 450mm radius clamped into a frame with no heat, which is how curved canopy and barrel-vault roof lights get built without a thermoforming oven. Avoid laser cutting polycarbonate; the edges discolour and the fumes are aggressive, which is the opposite of acrylic. If you also run acrylic work, our laser cutting guide explains why the two materials behave so differently under a laser.

Where Can You Buy Polycarbonate Roof Panels in Canada?

Buy from a supplier who can answer two questions in writing before you order: what is the thickness tolerance, and which side carries the co-extruded UV layer. If either answer is vague, the panel is a gamble no matter what is printed on the film. Our guide to choosing a plastic sheet distributor in Canada lays out the full red-flag list, and it reads the same for roofing.

FIDAR System stocks solid clear polycarbonate in all five thicknesses at our North York warehouse, alongside the full polycarbonate range, with warehouse pickup, same-week Ontario delivery, and freight quotes for the rest of Canada. We do not warehouse multiwall or corrugated profiles, because those are best ordered to the exact run length your roof needs. If your project calls for one of those formats, send us the details and we will help you specify the right panel and quote what we can supply. For glazing-grade clarity where impact is less of a concern, we also stock cast clear acrylic as the optics-first alternative. The major roofing brands worth knowing as you compare are catalogued by the Plastics Industry Association, which maintains material standards documentation for polycarbonate and related thermoplastics.

More Sheet Materials from FIDAR

Cast Clear Acrylic Sheets

Optical-grade clarity, 1mm–25mm thickness

From $37.97 CADView Product →

ACM Panels — Aluminum Composite

3mm aluminum composite panels — 8 face/back combinations

From $57.44 CADView Product →

PVC White Sheets

Closed-cell white PVC - six thicknesses, print-ready surface

From $25.57 CADView Product →

Extruded Acrylic Sheets (PMMA)

Clear, grey, and sparkling extruded PMMA — value-grade for fabrication

From $49.71 CADView Product →

TORONTO WAREHOUSE Unit 29, 601 Magnetic Drive, North York, ON, M3J 3J2

Phone: +1 (416) 857-7555 Office: +1 (416) 726-2428 Sales: +1 (647) 919-7557 Email: info@fidarsystem.com