Double vs Single Garage Doors: When to Use Two Singles vs One Double product guide

AI Summary

Choosing between one double garage door and two single garage doors is one of the most consequential decisions in garage design. The choice affects structural requirements, wind performance, opener costs, security, daily convenience, and overall street appeal. A single double door (up to 5500mm wide for B&D Roll-A-Door models) delivers a clean, modern look and requires only one opener — but it creates a larger unsupported span and a bigger wind-load surface. Two single doors (each up to 3150mm wide) allow a structural pier between openings, perform better in high-wind regions, and let you open one side independently — but they need two openers and two sets of hardware. This guide breaks down every factor so you can make the right call for your home.

The Basic Choice

At its simplest, a double garage houses two cars behind one wide door, while the same floor space can be divided by a central pier with a single-width door on each side. Both configurations fit the standard Australian double garage footprint of roughly 5.4 to 6.0 metres across the front wall. The difference is how you fill that opening.

A single double door spans the full width in one piece. It rolls up, folds, or lifts as a single unit and parks against the ceiling or around a barrel above the opening. Two single doors each operate independently — each one roughly half the total width, separated by a structural column or brick pier typically 200–300mm wide.

Neither option is universally better. The right choice depends on your building structure, local wind region, aesthetic preferences, how you use the garage day to day, and your budget for doors and openers.

Structural Considerations

The structural implications are significant. A double garage door opening of 4800–5500mm requires a substantial lintel or header beam to carry the load of the wall and roof above without any intermediate support. This is a large unsupported span, and in masonry construction it typically requires an engineered steel lintel — often a significant structural element that adds cost during the build phase.

With two single doors, you introduce a central pier or column between the openings. Each opening is only 2400–2700mm wide, which is a far more manageable span for standard lintels. The pier itself carries load directly to the footing, dramatically reducing the engineering demands on the header. For renovations where you are cutting into an existing wall, two singles can be far easier to achieve without major structural modification.

In timber-framed construction, the same principle applies: a 5000mm+ header requires larger timber or steel members, while two openings of 2400mm each can often be spanned with standard framing.

If you are building new and the architect has already designed for a double opening, the structural cost difference is minimal — it is accounted for in the engineering. But if you are retrofitting or converting a space, two singles may save considerable structural expense.

Wind Rating Implications

Wind performance is where the physics of door size becomes critical. Wind pressure acts on the entire surface area of the door, and a double door presents roughly twice the area of a single door to wind forces. This matters enormously in Australia's higher wind regions.

B&D's Series 2 Roll-A-Door testing data illustrates the relationship clearly:

• At 3000mm width (single): Ultimate design wind capacity of 4.89 kPa outward / 4.30 kPa inward (0.5mm curtain)
• At 4000mm width: Drops to 3.97 kPa outward / 3.74 kPa inward
• At 5500mm width (full double): Further reduces to 3.04 kPa outward / 2.92 kPa inward

The wind pressure capacity decreases as door width increases because the curtain and guide system must resist force across a greater unsupported span. For homes in Wind Region A (most of southern Australia), a double door at 5500mm typically still meets requirements. But in Region B, Region C (cyclonic, such as parts of northern Queensland and Western Australia where regional wind speed reaches 66 m/s), or exposed coastal and elevated sites, two single doors may be the only way to achieve the required wind rating without moving to specialised commercial-grade hardware.

If your site is in a higher wind region or an exposed location, always check the certified wind rating for your chosen door width. Two singles inherently handle wind better because each door has a shorter unsupported span and lower total wind load per panel.

Design and Street Appeal

Aesthetics often drive the decision as much as engineering. The two configurations create very different looks on the front of a home.

One double door presents a single, uninterrupted surface. This reads as clean, contemporary, and minimal. It works particularly well with modern architectural styles, flat or skillion rooflines, and rendered facades. The door becomes a design feature in its own right — especially in Colorbond colours matched to the home.

Two single doors create a more traditional, symmetrical appearance. The central pier provides a visual break that can anchor the facade, particularly on wider homes where a single expanse of door can look out of proportion. Two singles suit heritage styles, Federation homes, and any design where the garage facade benefits from rhythm and proportion. The pier can be finished in matching brickwork, rendered, or clad to complement the home.

For homes where the garage is the dominant element of the street-facing facade (common in many Australian estates), two single doors can reduce the visual weight of the garage and make the overall frontage look more balanced. Conversely, if the garage is set back or the facade is wide enough to balance a single door, the double gives a cleaner result.

Standard Sizes Available from B&D

B&D manufactures both roller doors and sectional doors across a wide range of sizes to suit single and double configurations.

Roll-A-Door (Roller Doors)

Single door sizes:

• Width: Up to 3150mm (Series 1)
• Height: Up to 3000mm (Series 1), up to 3600mm (Series 3)
• The door curtain is made approximately 60mm wider than the opening to allow 30mm overlap on each side

Double door sizes:

• Width: Up to 5500mm (Series 2 and Series 3 standard models)
• Width: Up to 5100mm (R3F model)
• Height: Up to 3600mm (Series 3)
• Minimum sideroom of 120mm required beyond door width on each side

Roll-A-Door Series available:

• Series 1 — Includes the Squareline Deluxe (R1D), Firmadoor (R1F), Rollmasta (R1R), and Mini Warehouse models. Available in standard and wind-locked configurations.
• Series 2 — Multiple profile options including Traditional Low Profile (R2L), Light Industrial (R2F), Traditional Industrial (R2I), and Traditional Wideline (R2W). Material is Colorbond steel in 0.4mm or 0.5mm thickness.
• Series 3 — Square-line profiles including Maxi (R3F), Squareline Industrial (R3I), and Squareline Wideline (R3W). Also Colorbond steel construction.

Panelift (Sectional Doors)

Single door sizes:

• Width: Up to 3150mm for standard residential configurations
• Height: Up to 3000mm (standard), taller options available

Double door sizes:

• Width: Up to 5500mm for standard residential configurations
• Height: Up to 3600mm
• Door is mounted behind the opening with minimum 120mm sideroom

Panelift models include:

• Panelift (PFT) — Features Pinchfree hinge design for safety
• Panelift Icon (PFI) — Premium sectional option
• Panelmasta — Commercial and industrial applications

Sectional doors are constructed as rigid sections hinged together, with each door tailor-made to suit the required size. Panels are equal-sized throughout with evenly spaced inserts.

Opener Requirements

This is where the cost equation shifts noticeably between configurations.

One double door requires a single opener. For a Roll-A-Door, the GDO-6v4 EasyRoller handles single and double doors up to 110kg (approximately 16.5m²), making it the standard residential choice. It features Tri-Tran+ (TrioCode 128) encryption, a 600N motor with 7-year warranty, and LED courtesy light. For heavier double doors, the GDO-12 Hiro offers superior pulling power in a slim profile with optional smart capability.

For a double sectional door, B&D's Controll-A-Door range applies, with models including the Smart DSO-3, Secure DSO-2, and Select DSO-1.

Two single doors require two openers — one for each door. That means purchasing two GDO-6v4 EasyRollers (for roller doors) or two Controll-A-Door units (for sectional doors). You also need two sets of remotes, two sets of safety beams, and two wall-mounted control panels.

The practical cost impact: two openers typically cost 60–80% more than a single opener (not quite double, because installation labour for the second unit is incremental rather than full-price). However, you gain redundancy — if one opener fails, you still have access through the other door.

Security

B&D's Auto-Lock system provides automatic security locking for garage doors. When the door closes, the Auto-Lock slides a bolt into the guide track automatically, securing the door whether power is on or off. Key features include:

• Automatic operation — locks engage every time the door closes, no manual action needed
• Emergency manual release — a lock/unlock button allows manual disengagement during power outages
• LED status indicators — red (locked), green (unlocked), flashing (low battery or communication issues)
• Wireless basestation module — enables remote monitoring of lock status

The Auto-Lock is compatible with B&D sectional doors (Panelift, Panelift Icon, Panelmasta, and others) and Roll-A-Door systems including Roll-A-Door Neo.

With two single doors, you install two Auto-Lock units. This creates genuine redundancy: if one lock or opener has an issue, the other door remains fully secured and operational. An intruder would need to defeat two independent locking systems rather than one.

With one double door, a single Auto-Lock secures the entire opening. It is simpler and less expensive, but represents a single point of failure for the full-width opening.

For homes where the garage provides internal access to the house (an attached garage with an internal door), security of the garage door is particularly important. Two singles with independent Auto-Lock units provide a stronger security posture.

Practical Day-to-Day Use

The daily experience of using your garage differs meaningfully between configurations.

Two single doors let you open one side only. If one car is out and you just need to grab something from the garage, you open only the relevant door. This is faster (less door mass to move), more energy-efficient (less conditioned or sheltered air lost), and more secure (the other bay stays locked). It also matters if you use part of your garage as a workshop — you can keep one side closed and sheltered while working with the other side open for ventilation or access.

A double door is all-or-nothing. Opening it exposes the entire garage interior. This is fine for most daily use, but less ideal if you have a mixed-use garage or want to minimise exposure to weather when only accessing one side.

Parking flexibility also differs. With a double door, you have maximum manoeuvring room — the full opening width is available, which makes parking large vehicles, trailers, or boats easier. Two singles with a central pier reduce each opening width by the pier dimension (typically 200–300mm total), and you lose the ability to angle a wide vehicle across both bays.

If you regularly park a boat, caravan, or wide trailer in your garage, a double door is often the only practical option.

Price Comparison

The total cost comparison depends on several factors:

Door cost:

• One double roller door is generally 30–50% more expensive than a single roller door of equivalent specification, but significantly less expensive than two single doors combined
• Two single doors typically cost 50–70% more in total door cost than a single double door

Opener cost:

• One opener for a double door vs two openers for two singles
• Two openers represent roughly 60–80% additional cost over a single unit
• Additional remotes, safety beams, and wall buttons are also doubled

Installation cost:

• A single double door is one installation visit with one set of tracks, brackets, and hardware
• Two single doors require two complete sets of hardware but can often be installed in the same visit
• The central pier (if not already existing) adds masonry or framing cost

Structural cost:

• A double opening requires a heavier lintel — potentially significant in masonry construction
• Two singles use standard lintels with a load-bearing pier — often less expensive structurally

Overall: For new builds where the structure is already designed for either configuration, the total cost of two singles (doors + two openers + pier) is typically 40–70% more than a single double (door + one opener). For retrofits, the structural savings of two singles can partially offset the higher door and opener costs.

Which B&D Products Work Best

For a Double Garage Door (Single Wide Opening)

Roller door: B&D Roll-A-Door Series 2 in Traditional Wideline (R2W) or Series 3 Squareline Wideline (R3W) — both available up to 5500mm width in 0.5mm Colorbond steel for maximum strength and wind performance at double widths.

Sectional door: B&D Panelift or Panelift Icon — tailor-made to your opening dimensions with Pinchfree hinge design and extensive colour and insert options.

Opener: GDO-6v4 EasyRoller for standard-weight doors (up to 110kg), or GDO-12 Hiro for heavier or demanding applications. For sectional doors, Controll-A-Door Smart DSO-3 for premium features or Secure DSO-2 for solid everyday performance.

Security: Single Auto-Lock unit for the full opening.

For Two Single Garage Doors

Roller door: B&D Roll-A-Door Series 1 Squareline Deluxe (R1D) — the premium single-width roller door, available up to 3150mm wide and 3000mm high, with wind-locked option for higher wind regions.

Sectional door: B&D Panelift or Panelift Icon in single-width configuration — delivers all the design flexibility of a sectional door with independent operation per bay.

Opener: Two × GDO-6v4 EasyRoller units (roller doors) or two × Controll-A-Door units (sectional doors). Each operates independently with its own remote and safety system.

Security: Two × Auto-Lock units for independent, redundant locking on each door.

Frequently Asked Questions

Can I fit one double door in an opening designed for two singles? Yes, if the central pier is removed and replaced with an appropriate lintel or header beam to span the full width. This requires structural engineering assessment and council approval in most jurisdictions. The reverse (splitting a double opening into two singles by adding a pier) is generally easier structurally.

What is the maximum width for a B&D double garage door? B&D Roll-A-Door Series 2 and Series 3 models support a maximum door width of 5500mm (including overlap). The R3F model has a maximum of 5100mm. Panelift sectional doors are tailor-made and can accommodate similar widths. The actual clear opening will be approximately 60mm less than the door width to account for side overlap.

Do two single doors cost more than one double door? Typically yes. Two single doors plus two openers and doubled hardware will cost 40–70% more than a single double door with one opener, assuming equivalent specifications. However, structural savings in some retrofit situations can narrow the gap.

Are two single doors better in cyclonic wind regions? Generally yes. Each single door has a shorter unsupported span and lower total wind load surface area. B&D's wind rating data shows that a 3000mm-wide door achieves significantly higher wind pressure ratings (4.89 kPa outward) compared to a 5500mm-wide door (3.04 kPa outward) in the same series and material specification. In Wind Region C with terrain category 2 (66 m/s regional wind speed), two singles may be necessary to meet the required ratings.

Can I automate just one of two single doors? Yes. You can install an opener on one door and leave the other as manual operation with a lock. This is a common approach for garages where one bay is used daily (automated) and the other is used for storage or occasional access (manual). You can always add a second opener later.

What if I need to park a boat or wide vehicle? A single double door is usually the better choice. The full opening width (up to approximately 5440mm clear opening) provides the manoeuvring room needed for boats, caravans, and wide trailers. Two single doors with a central pier reduce each opening to roughly 2400–2700mm, which may not accommodate wider vehicles or the turning radius needed to angle them in.