Metal and Polycarbonate Awnings: Aluminum, Steel, Copper, Polycarbonate and Glass

Choose a rigid awning instead of fabric when you want a permanent, waterproof cover that needs little upkeep and can be designed to handle snow. Aluminum is the default for window and door awnings because it is light, does not rust and is affordable. Polycarbonate gives rain protection while keeping light, steel suits long spans and heavy-duty commercial work, copper is an architectural accent that ages to a green patina, and glass offers the cleanest look at the highest cost with strict safety glazing rules. The trade-offs are less flexibility (they do not retract), more noise in rain, and more heat under some materials. Fabric options are compared in the awning fabric guide.

Rigid awning materials compared

Aluminum

Aluminum is the most common rigid awning material in the US. It does not rust because it forms a thin oxide layer, and it is usually finished with baked enamel or powder coating. Powder-coated aluminum frames commonly last 15 to 25 years or more. Styles range from classic ribbed or scalloped window awnings to insulated sandwich-panel patio covers and louvered aluminum awnings that let air and some light through.

• Strengths: light weight, low maintenance, no rot or mildew, waterproof, good value. Typical aluminum window awnings run about $250 to $1,200 per window.
• Weaknesses: thin-gauge panels dent in hail and from ladders; rain is loud on uninsulated panels; heat radiates down from dark finishes; the look can read as dated on some house styles.
• What to check: panel thickness (thicker resists denting and spans farther), finish type and warranty, and whether the design has a stated snow and wind rating.

For a deeper look at the product category, see aluminum awnings.

Steel

Steel is stronger and stiffer than aluminum, so it spans farther with smaller members and is common in commercial canopies, gas-station style structures and frames that carry fabric or panels. Its weakness is corrosion. Steel awnings need hot-dip galvanizing, a quality paint or powder coat, or both, and any scratch that reaches bare steel will rust. Weathering steel develops a stable rust-colored surface by design but can stain masonry and paving below with runoff.

• Good fit: long spans, heavy snow regions with engineered designs, commercial and industrial buildings.
• Not ideal: coastal sites without careful coating and maintenance, or DIY installs, because steel is heavy and harder to handle and fasten.

Copper

Copper awnings are an architectural choice, most often seen as standing-seam or soldered hoods over bay windows, front doors and dormers. Copper does not rust; it oxidizes from bright metal to brown and, over years depending on climate, to a blue-green patina that protects the metal. It is long-lived when properly installed, but expensive and typically fabricated by sheet-metal specialists.

Polycarbonate

Polycarbonate is a tough, impact-resistant plastic sheet that lets light through while shedding rain. It is popular for door canopies and patio covers where people do not want to darken the house.

Solid vs multiwall

• Solid sheet looks like glass, transmits the most light, and is very impact-resistant. It can let a lot of heat through when clear.
• Multiwall (twin-wall or triple-wall) has internal channels. It is lighter for its stiffness, diffuses light, insulates better, and is quieter in rain. The channels must run in the direction of slope so condensation drains, and the ends must be closed with breathable tape or end caps to keep out dust and insects.

UV, tint and heat

Polycarbonate itself absorbs most UV, which protects people below, but the sheet degrades and yellows without a UV-protective surface layer. Quality roofing sheet has a co-extruded UV layer on one face that must face the sun; installing it upside down is a common and costly mistake. Clear sheet lets through more solar heat, so in hot climates tinted (bronze, gray) or heat-reflective opal grades keep the space underneath more comfortable. Color and heat trade-offs are discussed in awning colors and heat, and UV in UV protection and awnings.

Thermal expansion

Polycarbonate expands and contracts much more than aluminum or glass, roughly three times as much as aluminum. Sheets need oversized fastener holes or glazing bars that let them slide, and gaps at ends and edges.

Acrylic (PMMA) sheet is sometimes sold as an alternative. It is clearer and more scratch-resistant but much less impact-resistant, so polycarbonate is the usual choice where hail or falling branches are a concern.

Glass

Glass canopies offer a clean, modern look and do not yellow. Building codes treat glass overhead as sloped glazing, and the International Building Code's provisions on sloped glazing and skylights restrict it to safety glazing types, most commonly laminated glass, which stays in place if it breaks, with specific conditions and screening rules for other types. Glass is heavy, so brackets, tension rods and the wall structure must be designed for it, and installation is a job for a glazing contractor. Expect the highest cost of any awning material, and plan for regular cleaning, since dirt and bird droppings show clearly from below.

Snow load: what rigid awnings can and cannot carry

Only rigid awnings and patio covers that are engineered for it should ever be expected to carry snow. Fabric awnings, especially retractables, must be retracted before snow; see winterizing awnings.

Snow weight varies enormously with how wet and packed it is. FEMA guidance gives rough rules of thumb: about 10 to 12 inches of fresh snow or about 3 to 5 inches of old, packed snow each weigh roughly 5 lb per square foot, so 2 ft of old, packed snow works out to roughly 25 to 40 lb per square foot by the same arithmetic. Ice is heavier still.

Design snow loads are set locally from ground snow load maps (based on ASCE 7) adopted in the building code. If you live in a snow region:

• Ask for the product's rated snow load in pounds per square foot and compare it with your local design value from the building department.
• Expect permits for attached patio covers in many jurisdictions; the International Residential Code includes an appendix for patio covers that many areas adopt. See awning permits and HOA rules.
• Avoid placing a canopy where a main roof dumps snow onto it, or add snow guards on the roof above.
• Clear heavy accumulations with a roof rake from the ground, not by climbing onto the canopy.
• Check that the wall it attaches to can carry the load: fastening into a rim joist or studs, not just siding. See mounting awnings on brick, siding and stucco.

Rigid vs fabric: who each is for

• Rigid suits you if you want year-round rain cover over a door, walkway or patio, you are in a snow region and will buy an engineered product, or you do not want to clean and re-cover fabric.
• Fabric suits you if you want shade only when you want it (retractable), you prefer a canvas look, or you want the cooler, breathable shade of woven acrylic. See retractable vs fixed awnings.
• Consider a full patio cover if the structure will be large and needs posts and footings; see awning vs patio cover.

Rain performance across all materials is compared in waterproof vs water-resistant awnings. To estimate costs for window, door and patio options, use the awning cost calculator, or let the fabric selector tell you whether metal is a better fit than fabric for your situation.

Frequently asked questions

Are aluminum awnings better than fabric?

They are better for permanent, waterproof, low-maintenance cover, and powder-coated aluminum often lasts 15 to 25 years or more. Fabric is better if you want retractable shade, a softer look, or cooler air underneath, since breathable acrylic does not trap heat like a metal panel. Aluminum is also louder in rain unless insulated, and thin panels can dent in hail.

Can a polycarbonate awning hold snow?

Only if the product is engineered and rated for your local snow load and installed as specified. Many lightweight door canopies are not. A foot of fresh snow weighs roughly 5 lb per square foot, while packed or wet snow can reach 20 lb or more, so check the rated load in pounds per square foot against your local requirement and clear heavy accumulations safely.

Does polycarbonate block UV?

Polycarbonate absorbs most UV radiation, so people beneath it are well protected from direct UV coming through the sheet. Quality roofing sheet also has a co-extruded UV-protective layer on the sun side to stop the plastic itself from yellowing and becoming brittle. That layer must face up. Scattered and reflected UV can still reach you from the open sides.

Why are copper awnings so expensive?

Copper sheet costs much more than aluminum or steel, and copper awnings are usually custom fabricated and soldered by sheet-metal specialists rather than mass-produced. In return they are very long-lived and develop a protective patina. Installers must use compatible fasteners and keep copper away from aluminum and galvanized steel to avoid galvanic corrosion.

Is a glass awning safe?

A properly designed glass canopy is safe when it uses code-compliant safety glazing, most commonly laminated glass that holds together if broken, and brackets and fixings engineered for its weight. Building codes regulate overhead glass as sloped glazing, so a permit and a glazing contractor are typically required. Confirm the requirements with your local building department.

Sources and further reading

• International Code Council: International Building Code, Chapter 24 (Glass and Glazing, including sloped glazing and skylights) and Chapter 31 (Awnings and Canopies)
• International Code Council: International Residential Code, appendix on patio covers
• American Society of Civil Engineers: ASCE 7, Minimum Design Loads and Associated Criteria for Buildings and Other Structures (snow loads)
• Federal Emergency Management Agency (FEMA): Snow Load Safety Guide
• Copper Development Association: architectural copper design guidance