Internal - SF45

Internal bifold doors - SF45

Secured by Design

When thermal performance is not important you can save money by using our internal and commercial bifold doors. This could be as a room divider for example between the kitchen and the dining room or for commercial premises.

SUNFLEX folding doors lead the way in innovation and design setting the standards for other companies to follow. Rather than emphasising on only one or two elements that make the SUNFLEX doors stand out there are countless features that makes the SF45, head and shoulders above the rest. Slim sight-lines, contemporary, square edged profiles throughout and colour matched furniture in line with the frame make SUNFLEX doors the best looking on the market.


  • The SF45 is an all aluminium system which has a slimline frame only 55mm front to back. Creating a wider opening than other folding doors when stacked open. Maximise your opening with the slimmest and neatest stack of folding doors on the market.
  • Slim sightline of only 115mm.
  • Glazing accommodated of 8mm, 26mm, 28mm, 30mm or 36mm.

This system features the below features and benefits:

  • Modern slimline square edged aluminium profiles.
  • All handles are finished in-line with the door frame providing an uninterrupted view through the glass. Alternatively a horizontal handle with a latch can be requested for a more traditional operation.
  • Aluminium framework is assembled with patented moulded internal corner blocks and machine mitred at the corners rather than the cheaper butt jointed alternatives.
  • Officially tested to ensure they really do keep bad weather outside with the weathered track.
  • One of the most weathertight aluminium systems available on the market with 900Pa water tightness (Class 9A) and 600Pa BS EN 12207 air permeability (Class 4) with our standard weathered track.
  • Resistance to wind load 1,600Pa (Class A4).
  • EPDM black gasket around the door which is an extremely durable synthetic rubber. We feel that a long life weather tight seal is more important than offering a colour matched inferior.
  • Double rebated top and bottom tracks offering a tight compressed seal.
  • Awarded Secured by Design accreditation. Designed and manufactured and installed to police preferred specification.
  • Multipoint locking system, comprising of hidden top and bottom shootbolt locking with additional side locking point on lead door panels.
  • Five-lever Euro profile cylinder complying to British Insurance Standards and BS3621.
  • Internally glazed as standard preventing the glass being easily removed from the outside.
  • Hinge pins secured by internal grub screws ensuring panels cannot be separated.
  • Slim 8mm gasket between panels so nothing substantial can be levered between the panels.
  • If not required ask for no key lock to the outside of the doors. Offers the doors a cleaner look externally and less opportunity for any potential burglar. 
  • Unique to SUNFLEX the top and bottom shootbolt locking can be doubled with our twin lock upgraded. The locking system of one panel is internally linked to the adjacent panel providing four locking bolts rather than two. This upgrade is not available with any other manufactures’ folding door.
  • Toughened safety glass would be used as standard making this hard to smash but this can be upgraded to laminated security glass.
  • Acoustic performance tested at Rw=36dB with suitable double glazing. Further upgrades available.
  • Choice of thresholds with a DDA compliant (Document M) flush track recessed in to the floor sealed with a twin brush pile and a nylon strip for a virtually seamless connection between inside and outside. It is recommended for a sheltered area only and a slope away or drainage channel is then used on the outside. For a weather tight seal use our weathered track with a double rebate ideal for exposed locations. Additional sill sections available in varying projections. See track downloads.
  • Tolerance built in to cope with material expansion and contraction when installed to south facing elevations and for marginal lintel deflections.
  • Join two elevations together with our moveable posts of 90° or 135°. If you can hold up the roof above with either cantilevered steel or an internal or external pillar we can join the folding doors together at the corner.
  • Create a unique look to your property with faceted/curved sets up to 10° between panels.
  • 2,500mm2 or 5,000mm2 colour matched trickle vents can be incorporated within a 35mm add on section above the top track.
  • Vertical and horizontal midrails to divide the glass or plant on bars stuck on 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. Upon installation the fitter easily adjusts this with an Allen key for optimising the smooth operation.
  • Maximise your opening with panel widths up to 1,200mm and 3,500mm maximum panel height for narrower panels. A sliding post can be introduced at the running carriage position to offer greater balance to the doors in extreme situations. This enables us to provide larger panels and greater openings than anybody else. This is introduced for heights over 2,700mm, panel weights over 75kg and seven panels or more folding in one direction.
  • 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.
  • Stacking clip - Unique to SUNFLEX bifold doors our stacking clip, hidden in the top track, holds the doors open to ensure that the maximum opening is achieved, the doors do not start to close in the wind and helps prevents unwanted use by small children.
  • 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.
  • Five standard frame colours, Silver Anodised EV1, or in semi-gloss: Traffic White RAL 9016, Grey Aluminium RAL 9007, White Aluminium RAL 9006 or Anthracite Grey RAL 7016.
  • Choose from over 200 frame colours available including brushed steel, textured, woodgrain and extreme marine protection.
  • Handles are designed to almost disappear when colour matched to the frame or can be made a feature in stainless steel. Plastic D handle used at the hinge to pull the doors closed.
  • Subtle hinges are in line with the black gasket of the doors making the standard black hinge a popular choice. Alternatively these can be colour coded to the aluminium frame or stainless steel.
  • For powder coated aluminium we recommend a marine treatment if you are within 5,000 metres of the coast or around a swimming pool/chemical environment. We pre-anodise the aluminium frames making them porous and then quickly after this the frames are powder coated which is absorbed in to the frame. This ensures excellent adhesion of the paint to the aluminium and along with a cleaning regime is the best possible protection for powder coated aluminium doors in this environment. Not many companies offer pre-anodising as a marine finish. Alternatively we can provide the aluminium frames in a Silver Anodised finish as standard which does not have a painted surface and does not need the marine treatment. 


SF50 & SF50c
Panel catch

Panel catch for additional security to fix the pass door to the adjacent panel

Mushroom-head lock

Mushroom-head lock for optimal tightness and increased burglar resistance


Proper Sunflex handle series


Different kinds of locks available

Height adjustment

Later height adjustment of the running mechanisms possible – e.g. in case of subsidence

Assembly shoes

Assembly shoes allow a fast assembly and precise adjustment of the vertical frame profiles


Burglar-resistant fittings

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