Aluminium French and Single Doors: The Origin OB-36+ and OF-36+

For a kitchen onto a patio, a bedroom onto a balcony or a side return onto the garden, a pair of French doors or a single glazed door is often the better answer: simpler to use every day, with the full width of the door open as soon as you swing it.

Origin builds its slimmest hinged and folding doors, the OB-36+ and OF-36+, as French and single doors as well as bifolds. This guide explains the difference between them, the sizes, thresholds and security, and when a hinged door beats a folding one.

OB-36+ and OF-36+: What Is the Difference?

Both use the same slim profile: a 36 mm sash, 84 mm of frame between panes at the hinge and an 82 mm frame depth.

• OB-36+ can be built as a bifold of up to 14 panels, or as French, single and fixed doors. It also comes in Origin's Soho, Gallery and Georgian styles.
• OF-36+ is the same profile built as French, single and fixed doors only, with up to six panels in a set.

In practice, if your project mixes a bifold on the rear with French doors elsewhere, the OB-36+ keeps every door in the same family. If you only need hinged doors, the OF-36+ gives you the same profile and performance.

Sizes

Each opening door leaf can be up to 1,200 mm wide. On the OF-36+, sets run up to six panels, which lets you combine French doors with fixed glass panels either side for a wider glazed opening. Fixed panels can be up to 1,317 mm wide.

Low Thresholds

The OB-36+ and OF-36+ offer a 30 mm low threshold on hinged doors, which makes the step between kitchen floor and patio far less noticeable. Weathered thresholds are available for exposed openings. We advise on the right threshold for your opening when we survey, because exposure and the patio level both affect the choice.

Security and Thermal Performance

Both doors are tested to PAS 24:2022, the current edition of the UK security standard, with a multi-point lock, and the OB-36+ comes with a 3-Star Diamond cylinder as standard.

Thermally, a standard double-glazed unit gives a whole-door U-value (the measure of heat loss, where lower is better) of 1.4 W/m²K, which meets Part L, the energy-efficiency part of the Building Regulations, for replacement doors. An upgraded double-glazed unit brings it to 1.2 W/m²K, and triple glazing takes it to 0.78 W/m²K.

The Soho Style

The OB-36+ Soho style adds a traditional lock block and integral glazing divides, so a slim aluminium door reads like a steel-framed one. It suits period homes and kitchen extensions where the steel look is wanted without the weight of steel. Gallery and Georgian are Origin's alternative styles for the same door.

French Doors, Bifold or Sliding?

• French doors open fully in one movement and are the simplest to use every day. They suit openings up to around two door widths, or wider with fixed panels either side.
• Bifolds clear almost the whole opening, with panels stacked to one side, but have more frames when closed.
• Sliding doors have the fewest frames when closed, with around half the opening clear on a two-track slider and more on a triple track, and nothing swings into the room or the garden.

Our guide to bifold vs sliding vs French doors compares all three in detail.

Colours and Hardware

Popular finishes include Jet Black, Textured Black, Anthracite Grey and Hipca White, with more than 150 RAL colours and a marine-grade finish for coastal homes. Origin's Signature Knurled handles come in six PVD finishes, from Antique Brass to Brushed Black.

Frequently Asked Questions

What is the difference between the Origin OB-36+ and OF-36+?

They share the same 36 mm sash and 84 mm hinge sightline. The OB-36+ can be built as a bifold of up to 14 panels as well as French, single and fixed doors, and comes in Soho, Gallery and Georgian styles. The OF-36+ is built as French, single and fixed doors only, up to six panels.

How wide can Origin French doors be?

Each opening leaf can be up to 1,200 mm wide. Adding fixed glass panels either side, up to six panels in an OF-36+ set, creates a much wider glazed opening.

Do Origin French doors have a low threshold?

Yes. The OB-36+ and OF-36+ offer a 30 mm low threshold on hinged doors, with weathered thresholds for exposed openings.

Are Origin French doors secure?

Yes. The OB-36+ and OF-36+ are tested to PAS 24:2022, the current edition of the UK security standard, with a multi-point lock, and the OB-36+ comes with a 3-Star Diamond cylinder as standard.

Can French doors open outwards?

The OB-36+ can be configured to open in or out. Outward-opening doors keep the room clear and suit smaller kitchens; inward-opening doors suit balconies and openings where outward swing would block a path.

Next Steps

See the full specification and comparison table on our Origin bifold, French and single doors page, or browse every system on our aluminium French doors page. When you are ready, request a free quote or call 0800 861 1450.