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BSF70 bifold doors with roof lantern
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Optio BSF70 HI Aluminium Bifold Doors

Optio BSF70 HI aluminium bifold doors from AluK are a versatile sliding folding door system. Multiple panels can be used to meet a range of design specifications and all panels can be chosen with either an open out or open in functionality. Perfect for residential and commercial applications in both modern and traditional buildings.

  • Unique flush line pop-out handle
  • Square flush stacking panels
  • 4 stainless steel rollers track system
  • Chamfered and square bead options
  • PAS 24 security tested
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Product features

Design features

AluK Optio BSF70 HI aluminium bifold doors are industry leading doors designed for both ease of installation and superior performance. Combined with a sleek and stylish aesthetic appearance and excellent customisation capacity, they are a popular choice with installers and end-users alike. For larger scale installations, the Optio BSF70 HI bifold door can be specified with heavy duty rollers. This allows for larger expanses of glass and heavier overall door weights.

Product options

  • 28mm – 44mm glazing
  • 70mm frame size
  • Multi-point locking
  • Dual colour option
  • Maximum vent weight 100kg
  • Class 9A water tightness
  • Class 4 air tightness
  • U-values as low as 1.6 W/m²K (double glazing)
  • U-values as low as 1.4 W/m²K (triple glazing)


U-Value (Double glazing)

U-Value (Triple glazing)

Air tightness (Pa) (Standard threshold)

Water tightness (Pa) (Standard threshold)

Wind load (Pa)


3rd party configuration

Max vent weight

Sightline (Head)

Sightline (Cill)

Sightline (Jamb)

Sightline (Meeting stile)

Frame depth

Glazing options

Glazing thickness


1.6 W/m²K

1.4 W/m²K

Class 4 (600 Pa)

Class 9a (600 Pa)

Class AE2400 (2400 Pa)

PAS 24








Internal bead

24 - 40mm


1.6 W/m²K

1.4 W/m²K












Internal bead

24 - 40mm



Versatile aluminium bifold door system

The AluK Optio BSF70 HI aluminium bifold door system is a high performing and fully customisable door choice. It is available with chamfered and square bead options with its square flush stacking panels folding neatly to one side to create an extra-large opening. It functions on a four stainless steel rollers track system that is durable and smooth sliding. With multi-point locking as standard and glazing options between 28mm and 44mm, it is an excellent addition to any glazing installer’s product portfolio.

BSF70 open bifold doors

Frequently Asked Questions

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Contact Us

What are your lead times?

Lead times can vary per product. For stock PVCu colours we work to a 10-15 working day schedule. For more up to date lead times on any specific product e-mail us at where we will be happy to help.

Are your products compliant with new building regulations?

Our Eurocell PVCu range of products are fully compatible with all new build regulations. Quantum Windows has a number of secured by design certifications to provide you with peace of mind and our quality systems in place are all aimed at producing a quality product first time, every time.

Currently, our range of Aluminium double glazed Aluk 58BW HI Windows, Aluk 58BD HI Residential doors, EdgeGLIDE+ Sliding door and Unifold HI all have a U-value of 1.4 or below and are compliant with new building regulations. Our range of compliant products is always growing, so please give us a call for the most up to date information.

Please note that you will need to specify on your enquiry if you need your product to meet the new building regulations.

Where do you deliver to?

We deliver weekly to the West Midlands, Derbyshire, Leicestershire, Warwickshire, Oxfordshire, Berkshire, Surrey, West Sussex, East Sussex, Kent, Greater London, Hertfordshire, Essex, Suffolk, Cambridgeshire, Bedfordshire, Buckinghamshire. Norfolk and of course Northamptonshire.

aspects white open bi fold doors

I have been buying windows and doors from Quantum Windows for over 25 years. I have always found the pricing very competitive and the quality has been very high. On the rare occasion a problem has arisen it has been dealt with swiftly and efficiently. The office staff are always polite, friendly and professional and we have built a strong relationship over the last 25 years. The drivers are excellent. I know them very well and they have adapted to my ways of working and are always willing to help and accommodated me.

Craig Gutteridge

“We have dealt with Quantum Windows for 13 plus years, we find the staff to be courteous and polite and any queries we may have are dealt with promptly and efficiently, nothing is too much trouble”

Jackie - Accounts Dept

W R Enterprise Glass & Glazing Ltd.

We have been buying from Quantum Windows for almost 30 years now, they offer a wide product range and the Team have excellent product knowledge which is invaluable in an ever-changing market.

All team members are friendly, helpful and efficient, orders are processed with care and quotations provided promptly. I would have no hesitation in recommending Quantum Windows.

Vicki Webb

Clearview 2000 LTD

‘We have used Quantum Windows for many years now, we have always found them to be very easy to work with, the staff are all very helpful and friendly, they are always available to offer any help should we need it, excellent product!’


Chapel Windows

Glevum and Quantum have enjoyed an excellent working relationship for a number of years, working together to provide a high quality, value for money product offering and service for the end user.

As well as delivering a high quality product, the knowledge and experience of the staff at Quantum is invaluable to a customer in a market where Building Regulations are constantly changing.

Mike Donaldson

Glevum Design & Build

As installers of both PVCu and Aluminium to the New Build market, the importance of on time delivery is totally time critical.
Over the last 20 years Quantum windows have worked closely with PGB to partner with us and deliver our offer to site.
Highly professional, and a pleasure to have worked with them so closely over the years.

Phil Martin CEO

Portico CB Ltd

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