Aluminium bifold doors

Bring the Outside In

Award-winning bifold doors ideal for any home

Bespoke bifold door configurations available

Sunflex-trained and supported installers located nationwide

Aluminium Bifold Doors

35 Years of Bifold Door Innovation For more than 35 years SUNFLEX has led the way in the global design and manufacturing of industry-leading aluminium bifold doors.

With the enhanced requirements of Building Regulations, the SUNFLEX SF75eco offers the ideal combination of advanced thermal performance and stunning appearance. When stacked back the doors allow you to bring the outside in, creating completely unobstructed openings to connect your home and garden. When closed the advanced design and attention to detail help keep your home warm and the worst of the weather outside, out.

The SF75eco is manufactured with slender aluminium frames, featuring a patented 44mm thermal break, and is packed full of unique features not found on any other folding door on the market.

Like every SUNFLEX UK door, the SF75eco is handmade in a SUNFLEX factory, ensuring consistent manufacturing quality and genuine components throughout.

  • Superb energy efficiency With U-values from just 0.8W/m²K no aluminium bifold is more thermally efficient
  • Aesthetic appeal Slender frames and panels up to 3000mm high and up to 1200mm wide to maximise glass
  • Advanced security protection Carries prestigious Secured by Design™ award and exceeds requirements of PAS 24:2016 testing
  • Industry-leading performance Capable of superior water tightness (900Pa – Class 9a*) and air permeability (600Pa – Class 4*) testing performance
Secured by Design PAS Logo Build It Awards Winner

  • SF75eco

    Designed to be the most thermally-efficient bifold door, the SF75eco offers Passivhaus standard thermal performance and is specifically manufactured to accommodate a triple glazed sealed unit, and thanks to its advanced thermal break technology it can achieve an incredibly low U-value from just 0.8W/m²K† (based on a centre-pane of 0.5W/m²K) whilst maintaining the same usability and slender appearance that SUNFLEX UK doors are renowned for.

    Every SUNFLEX product is manufactured to strict standards of child safety. The SF75eco features an exclusive antiSLAM panel catch and finger cushioning gasket. Unlike typical magnet designs, the SUNFLEX Panel catch completely secures the lead door in place preventing the doors from being blown shut by the gusts of wind or from being operated by small children.

Frame depths 75mm
U-Value Triple Glazed From 0.8 W/m²K†
With centre pane of 0.5W/m²K
U-Value Double Glazed From 1.3 W/m²K†
With centre pane of 1.0W/m²K
Maximum panel width 1200mm
Maximum panel height 3000mm
Sightlines 117mm
Secured by Design™ Yes
Water tightness To 900Pa (Class 9a)*
Air permeability To 600Pa (Class 4)*
Wind load To 2000Pa (Class 5B)
Unique Locking panel catch Yes
Track options 2 – low-threshold or weathered track
Double rebated frames Yes

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

† Thermal performance is dependent on glass specification.


Threshold options

Our SUNFLEX bifold doors are available with a choice of two threshold options.

Our single rebated low threshold is ideal for creating a level transition between your home and patio or decking, featuring a 14mm upstand that is classed as an accessible threshold and meets the requirements of Building Regulations M.

Our double rebated weathered threshold features a 35mm upstand against the frames of the doors seal, providing the most comprehensive weather performance. Available with or without a sill.

Low threshold track
no sill

Weathered track
with sill


Colour options

All of our aluminium doors and windows are manufactured to the highest standards of performance and finishes with unrivalled attention to detail, including a premium powder coat finish which is cured on to the frames of the doors and more scratch-resistent and hardwaring than traditional liquid paint coatings.

For the perfect finish we have chosen a selection of the most popular colours for each system to hold in stock. In addition to our standard colours you can personalise your doors with a choice of more than 200 bespoke RAL colours.

SF75eco – standard colours

  • Anthracite Grey (RAL 7016) matt finish Anthracite Grey (RAL 7016) matt finish
  • Charcoal Grey Metallic (DB703) textured finish Charcoal Grey Metallic (DB703) textured finish
  • Jet Black (RAL 9005) matt finish Jet Black (RAL 9005) matt finish

SF75eco – popular bespoke colours

  • Slate Grey (RAL 7015) matt finish Slate Grey (RAL 7015) matt finish
  • Grey Aluminium (RAL 9007) semi-gloss finish Grey Aluminium (RAL 9007) semi-gloss finish
  • Traffic White (RAL 9016) matt finish Traffic White (RAL 9016) matt finish
  • Graphite Black (RAL 9011) matt finish Graphite Black (RAL 9011) matt finish
  • Sage Green (RAL 6021) matt finish Sage Green (RAL 6021) matt finish
  • Pearl Mouse Grey (RAL 7048) matt finish Pearl Mouse Grey (RAL 7048) matt finish

Why choose aluminium?

Aluminium is the perfect material for manufacturing bifold doors. It is strong and stable yet relatively lightweight, enabling us to create doors with slim frames that are maintenance-free.

To request a quote for a set of aluminium bi-folding doors, or any of our specialist door systems, use our postcode checker to find the nearest SUNFLEX distributor in your area.

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