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When homeowners want a corrosion‑proof door but can’t decide between metal minimalism and fiber‑reinforced toughness, the conversation inevitably becomes aluminum versus fiberglass. Both materials scoff at Raleigh’s humidity, yet they diverge on impact behavior, daylighting options, upkeep, and long‑term costs. Drawing on more than a decade of RJ Garage Door Services installations and service calls, here’s the no‑spin comparison.

Overview

Category	Aluminum	Fiberglass
Impact resistance	Dents on hard blows	Rigid; can crack
Panel weight (16 × 7 ft)	≈ 115 lb	≈ 150 lb
Typical R‑value	R‑6 (with foam)	R‑7 – R‑8
UV/color fade	Powder‑coat may chalk	Gel coat needs buff/wax
Maintenance	Quarterly rinse	Wash + polish every 2 yrs
Installed price*	$2.6 k (avg.)	$3.3 k (avg.)
Daylighting potential	Full‑view glass option	Limited lites
Recyclability	Infinite alloy loop	Poor; landfill likely
Hardware needs	Standard torsion/½ HP	Std. torsion/½ HP (heavier)
Warranty typical	20 yrs on finish/frame	20 yrs finish/panels

Strength & Everyday Impact Behavior

Aluminum’s 0.040‑ to 0.060‑inch sheeting offers respectable tensile strength, but it will crease when lawn‑equipment handles or basketballs strike the surface. Fiberglass couples glass strands with polyester resin, yielding a rigid shell that resists small bumps yet can crack under sharp blows. A six‑pound shot‑put in our shop test left a palm‑sized dent on aluminum but a star‑shaped fracture on fiberglass—resulting in a full section replacement. If driveway sports rule your weekends, aluminum is the safer bet; if your garage faces light hail but little human abuse, fiberglass holds its own.

Corrosion & Weathering Resistance

Both materials laugh at rust. Aluminum forms a self‑protecting oxide layer that stops further decay, though powder‑coat chalking appears after about a decade without an occasional wax. Fiberglass gel coats resist rust entirely but chalk if left unpolished. Coastal installs show aluminum surviving 5,000‑hour salt‑spray tests with mild film build‑up, whereas fiberglass surfaces developed surface haze that buffed out with marine polish. Bottom line: both thrive by the beach, but plan a light detailing schedule for fiberglass to keep colors rich.

Thermal Performance & Energy Bills

Raw metals conduct heat swiftly, so aluminum manufacturers inject polyurethane foam to reach R‑6. Fiberglass skins sandwich polystyrene blocks, achieving R‑7 – R‑8. Despite the headline numbers, aluminum doors with thermal breaks in the rails match fiberglass’s interior‑surface temps within two degrees in our July FLIR audits. For conditioned garages, either material keeps HVAC bleed minimal, but fiberglass edges ahead when budgets allow triple‑layer construction.

Maintenance & UV Longevity

Aluminum care is easy: rinse quarterly, spot‑treat powder‑coat scratches before exposed metal oxides. Fiberglass needs the same soap‑and‑hose routine plus a polish or clear‑coat every couple years to stop gel‑coat oxidation. Neglect that step and colors fade to matte pastel. If you’re allergic to ladders and buffing pads, aluminum pairs better with a carefree lifestyle.

Weight, Hardware Load & Opener Strain

The 35‑pound gap between a foam‑filled aluminum door (≈ 115 lb) and an equally insulated fiberglass door (≈ 150 lb) may sound minor, yet lighter aluminum panels tax torsion springs and belt‑drive openers less. Over ten years, our service logs show aluminum springs needing re‑balance about 1,500 cycles later than fiberglass. Both qualify for a ½‑HP opener, but aluminum glides off the line faster and lands softer, trimming motor amperage and wear.

Curb Appeal & Design Flexibility

Aluminum’s forte is modern architecture. Full‑view glass sections framed in satin black or anodized bronze transform garages into studio‑style spaces flooded with daylight. Fiberglass excels at faux‑wood illusions: photorealistic walnut, cherry, or driftwood prints beneath a UV‑stable gel coat. If you crave a glass‑heavy showroom vibe, aluminum wins; if your HOA loves timber aesthetics without wood upkeep, fiberglass steals the spotlight.

Environmental Footprint

Aluminum sits on top of the recycling food chain—nearly 75 % of all aluminum ever produced is still in circulation. Fiberglass heads mostly to landfill; embedded fibers complicate recycling. Operational carbon favors aluminum slightly because lighter doors cut transport emissions, yet fiberglass’s higher base R‑value claws back some eco points. Net score: aluminum for cradle‑to‑cradle recycling, fiberglass for marginally better insulation.

Installed Cost & Resale ROI

Invoices from 2025 show aluminum doors averaging $2,600 installed and fiberglass at $3,300. National Cost‑vs‑Value data pegs aluminum ROI at 88–92 %, while fiberglass sits at 88–90 %. Aluminum’s lower buy‑in improves payback, yet fiberglass’s wood‑grain aesthetics often command a modest appraisal premium in rustic neighborhoods. Run a comps check with your realtor to gauge which style buyers covet on your street.