Optio BSF70 HI Bi-fold Door


Why Choose Our AluK BSF70 HI Bi-fold Doors?

Enhance your design with our best-loved bifold door. Many thousands of discerning customers across the UK have selected the BSF70 HI bifold door system, enjoying the panoramic view and the unrivalled performance it delivers.

High Performance

In addition to the inherent strength of aluminium, the BSF70 HI combines security hinges and locking mechanisms with a unique heavy-duty roller design to provide the security and reliability demanded in high-traffic applications. The system also incorporates a pop-out T-handle design that allows for square flush stacking panels when doors are fully open.

The BSF70 HI offers superb air (Class 4 - 600Pa), water (Class 9A - 600Pa) and wind (Class E - 2400Pa) resistance, with exceptional test results, which gives you peace of mind that this durable door can withstand the extremes of British weather.

Security is assured with full PAS 24 security accreditation, which also ensures that the BSF70 HI can be fitted in new build projects which require compliance with Part L.

With U-values of 1.4 double and 1.1 triple, this door is an energy-efficient option for both new build and refurbishment projects.




Multiple panels can be added to accommodate the unique design specifications of the house, with the option to open in or out as required. The system’s narrow profile ensures that maximum glazing is achieved, flooding spaces with natural light.

With a floating mullion frame, the BSF70 HI bifold door can be opened up completely on two sides to enjoy uninterrupted views of your outside space.

The innovative, flush line pop-out handle allows panels to stack flush when they are fully open, adding to the sense of openness that can be achieved.

Technical performances

  Technical data
U value W/m²K 1.1-1.4 W/m²K
Wind load (Pa) Class E2400 (2400pa)


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Elevate your space with AluK's bifold doors, blending style and function seamlessly. Enjoy smooth operation, high security, and customisable options for a perfect fit. Explore our range today for unmatched performance and aesthetic appeal.

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