SUNFLEX aluminium bifold door

Aluminium bifold doors

Our SUNFLEX aluminium bifold doors add a special touch to every home design project. These exciting installations break down the boundaries between indoor and outdoor space for the ultimate enjoyment of your surroundings.

Aluminium bifold door in a contemporary interior designed room

The SF55s and SF75eco systems utilise the latest in thermal break technology, separating the internal and external faces of aluminium, providing excellent thermal properties. This enables SUNFLEX to manufacture some of the most advanced energy-efficient bifold door systems available.

Our range of SUNFLEX aluminium bifold doors provides a contemporary, modern look and a maintenance-free solution. With minimal sight lines, over 200 different colours, and single, double or triple glazing, this range will meet the demands of any project.

Trophy Icon

No aluminium bifold door is more thermally efficient

With it's patented 44mm thermal break and outstanding design, the SF75eco is the most thermally efficient aluminium bifold door on the market today. When triple glazed the system is capable of achieving an overall (frame plus glass) U-value of just 0.8W/m²K, making it suitable for even Passivhaus standard homes. The SF55s is capable of achieving 1.2W/m²K triple glazed (1.4W/m²K double glazed) meaning they comply with Building Regulations Part L for extensions, renovations and new-build homes.

A choice of systems

A system for any requirement

The SUNFLEX range of aluminium bifold doors includes a solution for any type of project. The SF55s is the ideal solution for those updating their home and it's attention to detail in design provides the ultimate in protection from wind and rain, The ultra-thermally SF75eco offers the ultimate in energy-efficient frames and is perfectly suited for those undertaking eco-home style builds. Both systems can be designed as straight sets of doors or configured with open corners or even faceted (or curved) designs for a real wow-factor.

Rosette Icon

Ten-year warranty

You can rely on the high quality of the SUNFLEX products we install, and buy with confidence with a full ten-year warranty* on our systems and workmanship. Plus, unlike some warranties, our guarantee is fully transferable if you decide to sell your home.

*Exclusions apply, please contact us for full details of warranty policy.

Secured by Design logo

High security

IDSystems is proud to have received the coveted Secured by Design Award for bifold doors – with the systems achieving Police-preferred specification for design and manufacture. The Secured by Design initiative aims to reduce crime by ensuring the effective design and installation of products to meet Police-approved security standards.

Thermal Quality Icon

Thermally efficient

Specifically designed to offer the best in thermal efficiency and extremely low U-Value, providing the lowest in CO2 emissions associated with reduced energy consumption and considerable savings in heating bills. The SF75eco can achieve industry leading thermal performance, with U-values from just 0.8W/m2K (based on a centre-pane of 0.5W/m2K), enabling the bifold doors to be installed on projects constructed to Passivhaus standard.

Smooth operation icon

Smooth operation

The SUNFLEX SF55s and SF75eco are fitting with stainless steel running gear, ensuring long lasting performance, effortless operation and a neat visual appearance.

Bifold doors with midrails

Optional glazing bars

For those seeking to add an Art-Deco style to their double-glazed bifold doors, we can add narrow glazing bars (alternatively known as mid-rails or plant-on bars) to the design of the doors to provide the much sought-after look of traditional neo-industrial steel doors.

Integrated Venetian and pleated blinds

Integral Venetian and pleated blinds

Enclosed within the sealed glass unit, our integral blinds offer privacy and protection from the sun

Featured Case Studies

Green-roofed, timber clad extension to a Victorian villa

This challenging project saw this Victorian villa extended to create an open plan living space filled with natural light. The largely glazed timber (sustainably sourced) clad extension houses the kitchen and dining area and facing the garden.

Luxury Edinburgh garden room guest apartment

Creating a luxury garden room apartment from an old stone store may not have been the most obvious route to take for the owners of this property in Edinburgh, but that is exactly what Sally and Dan Weatherly achieved.

Conversion of Victorian Methodist chapel

The complete, yet sensitive, renovation of this Victorian red-brick Methodist chapel overlooking an area of outstanding natural beauty required an innovative design to create a contemporary family home flooded with natural light throughout.

Get a quote for aluminium bifold doors

Please send us your details, along with measurements for the opening, and we'll get back to you with a quote.

    System*
    All fields marked with * are required.
    This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

    FAQs - Aluminium Bifold Doors

    Minus Icon
    Minus Icon

    How thermally efficient are bifold doors?

    With rising energy prices and legislation around climate change tightening energy efficiency of homes as never been under the spotlight more. Our SF75eco bifold doors are able to achieve U-values from just 0.8W/m²K (no aluminium bifold system can achieve lower) making them suited to the requirements of Passivhaus standard.

    Minus Icon
    Minus Icon

    How secure are bifold doors?

    All of our bifold doors are independently tested to achieve the PAS 24:2016 standard required by Building Regulations Document Q. In addition they also hold the prestigious Secured by Design™ award to meet the police preferred specification for security.

    Minus Icon
    Minus Icon

    Why should I choose IDSystems for my bifold doors?

    Quite simply nobody in the UK has been supplying, installing and supporting bifold doors on the scale we have for as long as we have. When we first imported folding doors from SUNFLEX in Germany almost 25 years ago very few people in this country even knew what a bifold door was, but over the past two decades we've learned pretty much everything there is to know about fitting them. From thousands of extension projects in London to the grandest of Grand Designs TV projects our bifold doors have become synonymous with quality, performance and unrivalled experience.

    Minus Icon
    Minus Icon

    Why is aluminium the best material for bifold doors?

    Aluminium is both strong and lightweight, meaning it has both the strength to stand up to being open and closed repeatedly whilst maintaining a lightness of touch and effortless operation. Unlike timber or uPVC aluminium won't warp, twist or expand in changing weather conditions so they'll continue to work perfectly, time after time, year after year.

    Minus Icon
    Minus Icon

    What does 'thermally broken' mean?

    Previous generations of aluminium windows were cast as a single aluminium frame so if the outside of the frame was cold, so was the inner surface. In winter, with cold temperatures outside and warm rooms inside this often turned to condensation on the frame itself. Modern aluminium windows and doors all feature a thermal break (usually made from polyamide) between an inner and outer aluminium frame. This thermal break prevents cold bridging between the two surfaces, not only preventing condensation but also enhancing thermal efficiency.

    Minus Icon
    Minus Icon

    What locks are used on bifold doors?

    All of our SUNFLEX aluminium bifold doors feature multipoint locking systems, with shootbolts extending into the top and bottom of the track and espagnolette locks securing the lead door in place. For additional security to may wish to consider installing your doors with a security laminate glass which shatters and holds in place rather than breaking into hundreds of little pieces.

    Minus Icon
    Minus Icon

    Can I have a flush track with my bifold doors?

    Whilst we can provide a completely flush track for our bifold doors we wouldn't typically recommend it. With a flush track there is no seal between the bottom of the doors and the track itself so there is no weather rating on the doors - making them suitable only for internal use or for very sheltered urban locations. For those seeking a flush connection between inside and out our low-threshold track features just a 14mm upstand against which the doors seal when shut - combining protection from drafts and the much sought after appearance. For more information on choosing the right track for your doors check out our blog.

    Minus Icon
    Minus Icon

    What is unique about the SUNFLEX bifold door handle?

    An exclusive innovation, the handles on all SUNFLEX bifold doors sit within the frame of the door rather than extending out over the glass and interrupting your view out. This attention to detail provides a sleek and uncluttered appearance and ensures the doors look stunning whether they are open or closed.

    Minus Icon
    Minus Icon

    Are bifold doors tested against wind and rain?

    It can be easy to confuse thermal efficiency with how well a set of doors protect you from wind and rain. Indeed, as strange as it sounds, it is possible for doors to be both ultra thermally efficient and drafty at the same time. Our SUNFLEX bifold door are independently tested for both air permeability and water tightness and, as you would expect, record industry leading performance for both.

    Minus Icon
    Minus Icon

    Can I install internal aluminium bifold doors?

    The vast majority of our aluminium bifold doors are installed externally, connecting an extension, renovation or new-build home with its patio or garden. However we can also supply and install internal bifold doors - ideal for use between a conservatory and internal rooms or a house or partitioning up open plan spaces. The SUNFLEX SF45 is a completely unique system that is designed specifically for this purpose.

    Our range of SUNFLEX aluminium bifold doors

    SUNFLEX SF55s

    Award-winning aluminium bifold door system packed full of unique features

    SUNFLEX SF75eco

    Highly engineered, ultra-thermally efficient aluminium bifold doors

    SUNFLEX SF75 aluminium bifold door

    SUNFLEX SF55s

    Award-winning aluminium bifold door system packed full of unique features

    The award-winning SUNFLEX SF55s sets the standard for the aluminium bifold door market and is amongst the most advanced aluminium bifold doors available, making it
    perfect for more complex configurations that include moveable corner posts or for extreme panel sizes.

    SUNFLEX SF75eco

    Highly engineered, ultra-thermally efficient aluminium bifold doors

    The SUNFLEX SF75eco bifold doors have been specifically designed to provide the ultimate in thermal efficiency with an incredible low U-value from just 0.8W/m2K when triple glazed. The SF75eco enjoys all the design features and benefits of the award-winning SF55s.

    Sight lines (intermediate frame widths)

    Having narrow sight lines maximises the view. Our bifold doors are engineered to have the thinnest possible sight lines.

    Open arrow
    SUNFLEX SF55s

    115mm

    SUNFLEX SF75eco

    117mm

    Frame depths

    We design our bifold doors so, when stacked, they provide a slim profile that maximises space and when closed they look narrow whichever angle they are viewed from

    Open arrow
    SUNFLEX SF55s

    55mm

    SUNFLEX SF75eco

    75mm

    Thermal performance

    Thermal performance of the doors is measured as a U-value. When comparing products it is crucial to compare the overall U-value of the system and not just the U-value of the sealed glass unit. The SUNFLEX bifold doors can achieve incredibly low U-values based on a centre-pane of 0.5W/m²K, with the SF75eco capable of achieving a figure low enough for use on Passivhaus standard projects.

    Open arrow
    SUNFLEX SF55s

    Double glazed: from 1.4W/m²K. Triple glazed: from 1.2W/m²K.

    SUNFLEX SF75eco

    Double glazed: from 1.3W/m²K. Triple glazed: from 0.8W/m²K.

    Panel sizes

    The maximum size of each individual glass panel installed in our sliding doors range.

    Open arrow
    SUNFLEX SF55s

    Width: up to 1200mm. Height: up to 3500mm

    SUNFLEX SF75eco

    Width: up to 1200mm. Height: up to 3000mm

    Opening direction

    Whilst the majority of bifold doors are installed in an outward opening configuration, inward opening doors are ideal for use with balconies or with small courtyard gardens.

    Open arrow
    SUNFLEX SF55s

    Inwards or outwards opening, stacking to one end

    SUNFLEX SF75eco

    Inwards or outwards opening, stacking to one end

    Gaskets

    The gaskets that seal the panels of the doors together when closed, providing a weather-tight seal, are made from an incredibly durable, synthetic EPDM rubber.

    Open arrow
    SUNFLEX SF55s

    Continuous triple rebated gaskets

    SUNFLEX SF75eco

    Dependent on configuration

    Thermal break

    Separating the external and internal aluminium frames of the door the polyamide thermal breaks prevent cold bridging, increasing the thermal performance of the system.

    Open arrow
    SUNFLEX SF55s

    Patented 24mm polyamide thermal break

    SUNFLEX SF75eco

    Patented 44mm multi-chambered polyamide thermal break

    Security

    Our bifold doors include shoot bolt locks that extend from the lead door and intermediate panels into the top and bottom of the track, whilst the lead door features a mushroom head lock into the side jamb.

    Open arrow
    SUNFLEX SF55s

    Multipoint locking with shoot bolts hidden in the top and bottom of the door panels and mushroom head lock on lead door.

    SUNFLEX SF75eco

    Multipoint locking with shoot bolts hidden in the top and bottom of the door panels and mushroom head lock on lead door.

    PAS 24 / Building Regulations Document Q compliant

    PAS 24 is the testing standard for security required to comply with Building Regulations Document Q. P1a glass (usually laminated glass) specification is required to meet Building Regulations Document Q approval.

    Open arrow
    SUNFLEX SF55s

    Yes

    SUNFLEX SF75eco

    Yes

    Secured by Design™

    The Secured by Design™ award marks the police preferred security specification for windows and doors

    Open arrow
    SUNFLEX SF55s

    Yes

    SUNFLEX SF75eco

    Yes

    Glazing options

    Double glazing is a minimum requirement for external doors and windows. Our standard double glazed units consist of a soft-coat Low-E (low emissivity) pane and argon gas-filled cavity which provides a centre pane U-Value of 1.0W/m2K. Over the standard, we can provide super-insulated double glazed units providing a centre pane U-Value of 0.5W/m2K whilst providing solar control.

    Triple glazing is becoming increasingly popular, especially in total new builds, as it provides the lowest U-Values possible and can be up to 40% more efficient than double glazing. Combining two panes of Low-E glass and two gas-filled cavities, glazing U-Values as low as 0.5W/m2K are possible with the added benefit of great sound reduction.

    Open arrow
    SUNFLEX SF55s

    Double glazed as standard

    SUNFLEX SF75eco

    Triple glazed as standard

    Manufactured in

    Each set of our bifold doors is handmade to the highest standards or quality and performance by experienced fabrictors

    Open arrow
    SUNFLEX SF55s

    Germany

    SUNFLEX SF75eco

    United Kingdom or Germany - dependent on configuration

    Severe weather rating

    Every set of doors and windows undergoes independent physical testing to assess the ability of the systems to withstand air and water. Water tightness is tested against BS EN 12208 standard with air permeability tested against BS EN 12207 standard.

    *Water tightness and air permeability test performance is dependent upon a number of factors including system track option, system configuration and panel sizes.

    Open arrow
    SUNFLEX SF55s

    Water tightness: from 900Pa (Class 9a). Air permeability: from 600Pa (Class 4)*

    SUNFLEX SF75eco

    Water tightness: from 900Pa (Class 9a). Air permeability: from 600Pa (Class 4)*

    Track options

    Our bifold doors come with a choice of 2 track options. Non-weather rated flush tracks are only typically recommended for internal or sheltered urban locations, but our low-threshold tracks have minimal 14mm upstands which are perfect for creating that flush appearance in urban or rural locations. Our ffully weathered tracks designed to offer the hightest protection against wind and rain and are therefore ideal for rural or exposed locations.

    Open arrow
    SUNFLEX SF55s

    2 - low-threshold or weathered track

    SUNFLEX SF75eco

    2 - low-threshold or weathered track

    Locking panel catch

    A truly unique and innovative feature, the SUNFLEX locking panel catch holds the lead door of the system in place when the doors are being opened, preventing the door from swinging shut.

    Open arrow
    SUNFLEX SF55s

    Yes

    SUNFLEX SF75eco

    Yes

    Running gear

    Our bifolds are manufactured with two styles of running gear, both ensuring ease of use and ultra-smooth operation of the doors.

    Open arrow
    SUNFLEX SF55s

    Concealed stainless steel running gear connected to the frame of the doors

    SUNFLEX SF75eco

    Nylon covered stainless steel wheels connected to the hinge of the door

    Moveable corner posts

    The integration of a moveable corner post allows the doors to open up a complete, unobstructed corner of a room

    Open arrow
    SUNFLEX SF55s

    Yes, for 90° or 135° corners

    SUNFLEX SF75eco

    Yes, for 90° or 135° corners

    Colour choices

    Our doors are available in a range of standard colours, alternatively you can select from an almost infinite choice of optional colours and finishes – or even opt for a dual colour door with different colours on the internal and external frames.

    Open arrow
    SUNFLEX SF55s

    Standard – Gun Metal Grey (DB 703) textured, Anthracite Grey (RAL 7016) matt or Jet Black (RAL 9005) matt.
    Bespoke - More than 200 RAL colours and finishes are available as an optional extra

    SUNFLEX SF75eco

    Standard – Gun Metal Grey (DB 703) textured, Anthracite Grey (RAL 7016) matt or Jet Black (RAL 9005) matt.
    Bespoke - More than 200 RAL colours and finishes are available as an optional extra

    Integral blinds

    We are able to fit integral Venetian blinds within the glazed unit, ensuring a totally dust-free environment which requires no cleaning or maintenance. These are very popular, especially on internally opening systems where curtains are not practical.

    Integrated blinds can be tilted to help prevent the build-up of excessive heat and glare of the sun during the daytime and provide privacy when closed. Blind units are manually operated with an ingenious magnetic control device.

    Open arrow
    SUNFLEX SF55s

    Optional

    SUNFLEX SF75eco

    Optional

    Trickle vents

    The requirement for trickle vents to provide background ventilation can be a requirement of Building Regulations Document F, depending on the type of project you are undertaking. IDSystems trickle vents are installed through the head track of the outer frame if required.

    Open arrow
    SUNFLEX SF55s

    Required, subject to the project and compliance with Building Regulations Document F

    SUNFLEX SF75eco

    Required, subject to the project and compliance with Building Regulations Document F

    Glass options

    Laminated glass: Improved security and UV reduction preventing furniture fading.
    Solar-control glass: Manufactured with an external coating that features reflective properties to reduce solar gain.
    Self-cleaning glass: Reduces the need to clean the glass, very useful in roofs.
    Obscure glass: Our satin deco is a stylish solution for areas requiring privacy.
    Low-iron glass: Improves the light transmittance through glass while providing some free energy.

    Open arrow
    SUNFLEX SF55s

    Options available: Laminated glass, Solar control glass, Self-cleaning glass, Obscure glass and Low-iron glass

    SUNFLEX SF75eco

    Options available: Laminated glass, Solar control glass, Self-cleaning glass, Obscure glass and Low-iron glass

    Glass types

    For new-build homes or for change of use projects (barn conversions etc) we fit laminated glass as standard to meet the requirement for P1a glass as specified by Building Regulations Document Q for security. For all other projects (extensions, replacements or renovations etc) we fit toughened glass to comply with Building Regulations Document N.

    Toughened glass
    Toughened glass has been heat tempered to increasing its strength over ordinary annealed glass by up to five times. Other than the strength the advantage of toughened glass is that should it break it would shatter into non-sharp pieces. It is also available with the widest variety of coatings and can be supplied in larger sheets than equivalent thickness laminated glass.

    When the glass is toughened it can suffer from some visual distortion making, meaning the face of the glass is not perfectly flat distorting some reflections.

    Laminated glass
    Laminated glass is manufactured by bonding two panes of annealed glass with a clear plastic interlayer. The benefit of laminated glass is that if it’s broken the glass will crack rather than shattering, improving security. In addition, laminated glass reduces bleaching of carpets, curtains and furniture by filtering UV rays that would usually penetrate the glass.

    The drawback of laminated glass is that extreme heat or cold can cause invisible defects in the glass to form a crack due to the two panes expanding and contracting independently. As the laminated glass is not toughened is does not suffer from the visual distortion that can occur to toughened glass during the toughening process.

    Open arrow
    SUNFLEX SF55s

    Toughened or laminated glass

    SUNFLEX SF75eco

    Toughened or laminated glass

    Aluminium bifold door showing large frames and wide opening

    Based in Germany, SUNFLEX GmbH has been designing and manufacturing folding door solutions for more than 35 years. Today their doors are supplied and installed across the globe, including parts of the world with some of the harshest and most extreme weather conditions on the planet.

    The bifold door panels can be made up to 1200mm wide and 2800mm high, while greater heights can be achieved by using sliding posts to achieve tall bifold doors up to 3500mm in height.

    Colour your life

    Our SUNFLEX aluminium bifold doors are available as standard in a choice of three polyester powder-coated finishes – Gun Metal Grey (DB 703) textured, Anthracite Grey (RAL 7016) matt or Jet Black (RAL 9005) matt.

    DB703 RAL 7016 and RAL 9005 colour swatches

    Alternatively the systems can be polyester powder coated to any stocked RAL colour (over 200 RAL colours) and even dual colour or textured finish. In addition, you can specify whether a matt, semi-gloss or full-gloss level of paint finish is required.

    For a timeless finish you can ever add internal timber cladding to the inside face of your doors with our SF55c and SF75c systems, ideal for those planning a timber framed home or seeking to match interior finishes and decor.

    IDSystems Colour Range
    Composite bifold door photo

    SUNFLEX

    Need a timber finish on the internal side of the doors? See our composite bifold doors