SUNFLEX folding sliding door systems are the all-rounders among folding sliding doors, boasting an exceptionally wide range of options: the uninsulated system for stylish interior room partitioning, the thermally insulated system for elegant side glazing of conservatories or summerhouses, and the highly thermally insulated system for patio access in passive houses. Thanks to the interconnected panels, they are particularly easy to operate – with a single movement, the entire glass front folds elegantly to the side. Slim profile views, a barrier-free threshold, and optional burglar resistance up to RC2 mean you don't have to compromise on any of your requirements. This ensures you'll find the perfect folding sliding door for every project, custom-made to your exact specifications and precisely tailored to your architecture.
Use the SUNFLEX configurator to create your project and individually configure the width, height, number of sashes, insulation level, and glass selection. In the final step, you choose a SUNFLEX specialist partner near you who will professionally handle the measuring, planning, and installation.
The transition between living space and patio is one of the most frequently used areas of a house. Unfortunately, it is often too narrow, too cumbersome, or fails to meet the demands of modern architecture. With SUNFLEX folding sliding systems, you can reimagine your patio access. The interconnected panels fold smoothly to the side like a fan, opening up the entire front. This creates a seamless transition between living space and garden. Thanks to slim profiles and a large glass area, the view remains unobstructed even when closed. The SF75 folding sliding door's maximum thermal insulation meets the highest energy efficiency standards, while the optional RC2 burglar resistance provides peace of mind.
Anyone wanting to use their conservatory year-round needs a folding sliding door that meets high thermal insulation requirements while still being easy to open. For insulated conservatories, the SF55 or SF55e are recommended as thermally insulated options, achieving Uw values as low as 0.9 W/m²K. In summer gardens used seasonally, the folding sliding doors of the uninsulated SF45, with their slim profiles, create an open and airy feel. All versions maintain a shallow installation depth and a delicate profile appearance. Combined with a SUNFLEX patio roof, this creates a light-filled conservatory or summer garden that can be fully opened in summer and reliably closed in winter.
Open-plan living spaces sometimes require flexible boundaries. SUNFLEX folding sliding systems are ideal as floor-to-ceiling glass folding walls between living and dining areas, as transparent partitions in offices, or as light-permeable walls in commercial spaces. When open, the panels fold neatly to the side, forming a narrow stack. When closed, they divide rooms and allow natural light to enter. The smooth and quiet gliding of the folding sliding doors makes the system perfectly suited for everyday use.
Restaurants, hotels, and cafes that want to fully open their terraces in good weather benefit from system widths of up to 22 meters and up to 20 leaves in a single unit. The storm-proof and burglar-resistant fittings ensure reliability even with continuous commercial use. The SF55 with thermal insulation is ideal for business entrances that need to be both impressive and energy-efficient.
SF45
non insulated aluminium system
SF45
SF55
insulated aluminium system
SF55
SF55e
insulated aluminium system
SF55e
SF75
highly insulated aluminium system
SF75
SF45
non insulated aluminium system
SF45
SF55
insulated aluminium system
SF55
SF55e
insulated aluminium system
SF55e
SF75
highly insulated aluminium system
SF75
SF45
non insulated aluminium system
SF45
SF55
insulated aluminium system
SF55
SF55e
insulated aluminium system
SF55e
SF75
highly insulated aluminium system
SF75
Project-specific structural analysis, connection details, and building physics calculations are the responsibility of the specialist planning and structural engineering team. In the final step of your configuration, you select your specialist partner.
SF45 – uninsulated:
SF55e – thermally insulated:
SF55 – thermally insulated:
SF75 – highly thermally insulated:
SF45, SF55, SF55e, and SF75 are aluminum-glass folding walls with interconnected glass panels. When the operating panel is opened, the connected elements fold together like an accordion and are parked laterally on the single-track floor rail. The result is an almost completely unobstructed opening, with the panels stored as a narrow stack against the wall. Whether the panels fold inwards or outwards, left or right, is freely selectable, as is the panel configuration.
The durable stainless steel carriage system ensures quiet, smooth gliding of the panels. Stability and security are provided by a locking mechanism in the floor and ceiling rails, and a safety catch reliably locks the operating panel in place during opening and closing. Various handles, lock types, and colors are available. SF55 and SF75 also offer a stylish SUNFLEX handle series, as well as optional Twin-Lock locking and a security package up to RC2.
The four systems cover all insulation levels, so you can find the ideal folding sliding door for every construction project at SUNFLEX.
Suitable for:
The defining feature of folding-sliding systems is their folding mechanism: the interconnected panels fold like an accordion, revealing the entire opening width. This allows for maximum opening with minimal space requirements.
In comparison: The SF25/SF30/SF35 sliding-folding systems rotate and slide each sash individually – ideal for loggias and balconies, but with a lower insulation level. The SF20/SF22/SF42 sliding systems slide the sashes linearly on multiple tracks – for very wide installations with many sashes, but without a full opening. The SF40/SF60/SF80 sliding window systems are fully insulated patio windows and doors with RC2 burglar resistance and mushroom-head locking bolts – the right choice when maximum airtightness and security are paramount, but a full opening of the front is not required.
The unique feature of the folding-sliding systems is their exceptional range: With SF45 to SF75, they are the only product family in the SUNFLEX range to cover all insulation levels from uninsulated to highly insulated.
A folding door sounds simple, but in practice many solutions fail for the same reasons: too much frame, too stiff operation, insufficient insulation, no burglar protection, or the panels get in the way when opening. SUNFLEX folding sliding systems solve these problems:
Yes, the SF55, SF55e, and SF75 are specifically designed for use as exterior folding sliding doors. They are thermally insulated, weatherproof, and stormproof, and are optionally available with burglar resistance up to RC2. The uninsulated SF45 is suitable as side glazing for covered outdoor areas.
The operating panel opens and is pushed to the side. The panels connected to it fold automatically like an accordion and glide together to the side along the single-track floor rail. The panels park at a 90° angle to the floor rail as a narrow stack to the side of the opening. Whether they fold inwards or outwards is freely selectable during configuration.
A folding sliding system requires sufficient space to the side of the opening to park the folded panels. If this space is not available, we recommend the SUNFLEX sliding systems. These folding sliding systems also feature continuous aluminum frames on each panel. For those who prefer a virtually frameless, continuous glass front, the SUNFLEX SF25/SF30 sliding-folding systems are a better choice. A completely closed, opaque folding door is not available in the SUNFLEX range.
SF45 is uninsulated and suitable for interior spaces and seasonally used exterior areas. SF55 and SF55e are thermally insulated, while SF75 is highly thermally insulated and meets the requirements of the German Energy Saving Ordinance (EnEV). Therefore, SF55, SF55e, or SF75 are recommended for permanent use as an exterior folding sliding door. The specific U-values depend on the glass type, sash size, and installation situation and are calculated on a project-specific basis.
SF55 and SF55e are both thermally insulated aluminum systems with identical dimensions and element heights. The difference lies in the test classes: SF55 achieves a higher resistance to driving rain (class E900) and a higher wind load class (B4) than SF55e (E750, A3/B2). Simply put, SF55 is better suited for more demanding locations, such as windy or heavily rain-exposed sites. SF55e is suitable for sheltered locations and can therefore be offered at a lower price. Furthermore, different carriage systems are used.
Yes, the SF55 and SF75 are optionally available with a security package up to resistance class RC2. This includes mushroom-head locking bolts, burglar-resistant fittings, and an optional twin-lock locking mechanism for added protection. All systems come standard with storm-proof and burglar-resistant fittings.
Yes, with SUNFLEX folding sliding doors, the floor track can be recessed so that the threshold is flush with the floor, eliminating tripping hazards. Barrier-free design according to DIN 18024 should be discussed with your SUNFLEX specialist partner early on, as this depends on the floor construction and installation situation.
A fixed price cannot be quoted, as it depends on the system width, height, number of sashes, insulation level, glass choice, and individual installation requirements. Use the SUNFLEX configurator to create your desired configuration and receive a transparent, project-specific quote from your specialist partner.
SUNFLEX distributes its systems exclusively through qualified specialist partners. These are metal construction and glass construction companies that handle consultation, measurement, and installation from a single source. You can quickly find a certified partner in your region using the SUNFLEX specialist partner search.
For decades, SUNFLEX has been developing and manufacturing sliding, folding, and glazing systems – with partners and locations worldwide. The SF45, SF55, SF55e, and SF75 folding-sliding systems are CE-marked and tested for air permeability, resistance to driving rain, and wind load at independent testing institutes. Global project experience – from private patio access to large-scale commercial facades – guarantees sophisticated systems and absolute planning reliability for both private homeowners and specialist companies.
