Sunflex SF55i

Aluminium - Sunflex SF55i Bifold Door

Pas 24 and SBD

The new & UK manufactured Sunflex SF55i is an innovative version of the award winning SF55s aluminium bifold door. Manufactured from the same slim line & square edge aluminium profile as the SF55s, measuring just 55mm front to back.

The SF55i aluminium bi-fold doors are the new entry level addition to the range, providing a top of the range specification for a mid-range price whilst sharing almost all of its unique key features, innovations and design characteristics of the award-winning SF55s system.


  • Panel to panels sightlines of only 117mm.
  • Panel widths up to 1200mm.
  • Panel heights up to 3000mm.
  • Double glazed Overall frame & glass 1.6W/m2K.
  • Triple glazed Overall frame & glass 1.3W/m2K.

Features & Benefits:

Why You Should Choose Us As Your Sunflex Distributor

  • With over 15 years of partnership we are one of the longest running Sunflex distributors in the UK.
  • We aim to be the most competitively priced UK distributor.
  • We offer design, supply, delivery and installation services . Leave it all to us.
  • We work on projects Nationwide. Domestic, commercial, big and small.
  • We offer a guarantee of up to 15 years.
  • We provide an inclusive CAD design package as standard and unlimited advice.
  • No obligation quotations and consultations.
  • Over 80% of our business is a result of recommendation or architect specification.

Contemporary Appearance

    • Narrow sightlines with only 117mm panel to panel mullion widths.
    • Modern slim line profiles and contemporary square beads. Matching windows, doors and sliding doors available. 
    • Specially designed colour coded handles sit in line with the frame to provide an uninterrupted view through the glass.
    • Option to have a traditional lever handle with latch to lead doors.
    • Framework assembled using patented internal corner blocks and mitred corners for a seamless profile.  unlike cheaper but jointed profiles.

Thermal Efficiency & Weather Tightness

 Officially tested and certified to ensure they really do keep bad weather outside.

  • Double glazed Overall frame and glass 1.6W/m2K.
  • Triple glazed Overall frame and glass 1.3W/m2K.
  • Accommodate glazed unit thicknesses of 28mm, 30mm or 36mm.
  • Acoustic performance tested at Rw=36dB. Further upgrades available.
  • Water tightness 300Pa - BS EN 12208 (Class 7A).
  • Air permeability 600 Pa - BS EN 12207 (Class 4) with our standard weathered track.
  • Resistance to wind load 1200 Pa - BS EN 12210(Class A3).
  • EPDM gasket around the door which is an extremely durable synthetic rubber. Offering a long life weather tight seal.

A good U-Value does not mean a door keeps out the wind and the rain. Make sure you check out a doors weather test results before you buy.


High Security

  • Advanced multipoint lock, comprising of a combination of side locking on lead door panel with hidden top and bottom shoot bolt locking on remaining panels.
  • Exceeds the requirements of PAS 24:2016, the security test for Building Regulations approved Document Q.
  • Carries the prestigious BSI Kitemark™ certification for quality.
  • Awarded Secured by Design accreditation, meeting a police preferred specification for security.
  • Unique to SUNFLEX bifold door systems the top and bottom shoot bolt locks can be doubled with our twin lock upgraded. This upgrade enables the locking system of one panel to be internally linked to the adjacent panel, providing four locking bolts rather than two.
  • Thin 8mm gasket between panels preventing anything substantial from being used to attempt to lever the doors open.
  • Hinge pins secured by internal grub screws ensure that the panels cannot be separated.
  • Five-lever Euro profile lock cylinder complies with requirements of British Insurance Standards and BS3621.
  • Option to have no key lock to the outside of the doors, creating a cleaner look and removing the temptation for a potential burglar to attempt to gain access this way.
  • Internally glazed system, preventing sealed unit of the glass from being removed from the outside.
  • Fitted with toughened safety glass as standard with the option to upgrade to laminated safety glass.

If not required ask for no key lock to the outside of the doors. For a sleeker look and less opportunity for any potential burglar. 

Built In Design

  • Designed to allow a built-in tolerance to cope with material expansion and contraction when installed to south facing elevations and for marginal lintel deflections
  • Available with 2500mm2 or 5000mm2 colour matched trickle vents incorporated within a 35mm add-on above the top track should you need to comply with Building Regulations requirements.
  • Option for horizontal or vertical midrails to divide the glass or choose plant on bars stuck to the glass for a more traditional look
  • A bottom running system with a four wheel running carriage manufactured from tough glass fibre reinforced polyamide set around a maintenance free sealed ball-bearing.

Child Safe

  • Panel catch - Unique to SUNFLEX bifold doors our locking black PVC panel catch is provided when there is an odd number of panels folding in one direction. This holds the single access door on to the next panel and when all the doors are stacked open the special design prevents the single door being detached from the next door for peace of mind in windy conditions. Also prevents unwanted use and promotes correct operation of the doors providing the correct counter weight for effortless operation.
  • Finger cushioning gasket situated on the edge of each door. This double gasket seal provides a cushioning effect if fingers were to be trapped. Making these doors safer than conventional, internal, single wooden doors that do not come with finger cushioning gasket. 

Wide Range of Finishes


  • Three standard frame colours, Anthracite Grey RAL 7016 Matt, Graphite Black RAL 9011 Matt, Slate Grey RAL 7015 Matt.
  • Choose from over 200 frame colours available including brushed steel, textured, wood grain and extreme marine protection.
  • Dual colour finish available (different internal and external colours).

Handles and hinges

  • Colour matched handles sit in line with the frames are designed to almost disappear whether the door is open or closed. Plastic D handle used at the hinge to pull the doors closed.
  • Standard frame colour orders have colour matched hinges, other frame colours can have colour matched hinges as an upgrade or the standard black hinges which are designed to fit seamlessly inline with the black gasket of the doors.

Marine and swimming pool environment finishes 

  • We recommend a marine treatment if you are within 5000 metres of the coast or around a swimming pool/chemical environment. Stainless steel handles would not be suitable for this location.

Threshold Options

Choice of 3 thresholds

Weathered track with double rebates offering peace of mind even in the most exposed of locations. One of the only bifold doors that can offer a double rebates on the bottom track which is why we achieve enviable weather test results ensuring that the outside is kept outside. On outward opening doors the internal finished floor can be level with the top of the track and then the step down to the outside can be as small as 3cm.

Low level track with single rebate low level Doc M compliant track recessed in to the floor with a single rebate. The floor on the inside and outside can be at the same level with the track in the middle sloping up only 14mm. This provides a single rebate for the doors to close tight against which is more weather tight than the flush track.

Non weathered flush track, Doc M compliant track recessed in to the floor with no rebates. Using a twin brush pile and a nylon strip for a virtually seamless connection between inside and outside. Whilst this is a very subtle detail it is recommended for a sheltered area only as there is not a continuous seal and reduces the weather rating with no guarantee against wind and water ingress which is a compromise for this contemporary look. A slope away or drainage channel is then recommended on the outside to prevent any water ever pooling up against this track.