Aluminum Bi-Fold Doors: Sizes, Panel Counts, and Other Specs (2025 Guide)
If you’re planning a large opening for a patio, storefront, or amenity space, Vetrina’s aluminum bi-fold doors provide wide, unobstructed views with flexible operation. This guide covers how to select the right size, panel count, and hardware, along with other helpful tips, and explains when a lift-and-slide or large slider might be a better option.
A recent project completed by Vetrina Windows with several sets of custom aluminum Bi-Fold Doors
What is a bi-fold door (and when should you use one)?
Bi-fold (folding) systems use multiple hinged panels that stack to one or both sides on a top and/or bottom track, creating a broad, clear opening. They’re ideal when you want:
Maximum opening width for indoor-outdoor living or high-traffic commercial entries
A traffic door (an operable single panel) for daily use without opening the entire system
Clean, contemporary lines with slim aluminum profiles
Standard widths & common panel layouts
Real-world panel widths typically fall within the 28–36 in (711–914 mm) range, depending on the hardware, profile, and glass used. Use the table below as a quick planning reference (final sizes depend on your chosen system’s module, jamb details, and structural conditions).
An eight-pane bifold door manufactured by Vetrina Windows for a conference space
How to choose your panel count in 3 steps
Measure the structural opening (clear width/height after framing).
Pick your daily path: decide where the traffic door should live.
Match width to modules: divide opening by ~30–36 in per panel to pick a clean, symmetrical layout (round to your system’s standard panel size).
Quick planner: opening width → suggested panel count
Tips
Top-hung vs bottom-rolling: Top-hung systems ride on an overhead track (crisper feel, floor detail flexibility). Bottom-rolling bears weight on the sill (useful if overhead structure can’t carry load).
One-way vs bi-parting: Bi-parting (panels stack to both sides) shortens stack depth at each jamb and often improves daily usability.
Thresholds, tracks, and accessibility
Flush/low-profile thresholds minimize tripping hazards and meet many accessibility needs in commercial settings.
Drained sills handle weather; match sill type to exposure (covered vs exposed).
Interior transitions: Plan flooring thicknesses early so surfaces align cleanly.
Energy & performance (why aluminum still wins)
Thermally broken aluminum frames control conduction while maintaining narrow sightlines.
IGU choices (low-e, laminated, argon, triple-pane where needed) tune U-factor, SHGC, and acoustics.
Air/water/structural (AAMA/NAFS) performance is driven by hardware quality, gasketing, and fabrication precision—not just glass.
Cold climates: Combine thermally broken frames with high-performance glass packages and correct installation (back dams, continuous flashing) for comfort.
Vetrina Windows manufactured several sets of Bi-Fold doors for a pizza parlor in Grand Island, NY
Bi-Fold vs. Lift & Slide vs. Sliding: a quick decision guide
Choose bi-fold if you need: the widest clear opening, a traffic door, and flexible partial stacking for events.
Choose lift-and-slide if you want: large glass with minimal mullions, very smooth operation on big panels, and excellent air/water performance.
Choose multi-panel sliders if you need: value, simplicity, and strong weather resistance with stacking or pocketing panels.
Specification checklist (copy/paste into your RFP)
Opening width x height; desired clear opening target
Panel count & handing (left, right, bi-parting) + traffic door location
Top-hung or bottom-rolling preference
Sill type (flush/low-profile/drained) and interior flooring thicknesses
Thermal (target U-factor/SHGC) and acoustic needs
Glass: low-e type, laminated/tempered, argon, thickness, coatings
Finish: standard powder vs anodized, custom RAL
Hardware: multi-point, profile cylinders, security tier
Performance: design pressure, water infiltration target, air leakage class
Integration: weatherproofing details, screens, shades, bug door options
Recent project showcase (see the rest here)
A more detailed quote request form can be found here.
FAQs
What size opening do I need for a 3-panel bi-fold?
Plan approximately 8–10 ft of width for three panels, depending on your chosen panel module and traffic door needs. We’ll optimize the layout to your exact opening.
Are aluminum bi-fold doors energy-efficient in cold climates?
Yes, when you pair thermally broken frames with the right IGU (low-e, argon, laminated where needed) and ensure proper installation and air sealing.
Top-hung or bottom-rolling: which is better?
Top-hung offers a crisp feel and clean sill details if your structure can carry the load. Bottom-rolling is ideal when overhead support is limited.
Can I get a low/flush threshold and still manage water?
Yes. We’ll specify drained, thermally broken sills appropriate to exposure and integrate them with flashing to balance accessibility and weather performance.
When is a lift-and-slide a better choice than a bi-fold?
For very wide spans where you want fewer vertical lines and ultra-smooth operation, lift-and-slide can be the better daily-use solution.