Sliding door systems

• Extremely high glass area up to 98% (panoramic windows)
• Reliable burglar resistance up to RC2
• Extra narrow profile views: 21 mm or 30 mm
• Maximum width 13,800 mm, minimum 1,000 mm. Maximum height 4,000 mm, minimum 500 mm
• 2 to 6 panels, 2-track or 3-track
• Opening direction: left and/or right
• Maximum panel weight: SF40 up to 400 kg, SF60/SF80 up to 800 kg
• Flush-mounted threshold (barrier-free according to DIN 18024)
• Ball-bearing stainless steel rollers and stainless steel tracks
• Integrated closing mechanism
• Three sealing levels in the labyrinth seal, meeting the highest airtightness requirements
• Steel reinforcement at the center joint is possible for high wind loads
• Combinable sliding, fixed, and corner elements (e.g., 90° corners)
• Lowest U-values ​​from 0.75 W/m²K depending on size and glazing (SF60/SF80)
• Glazing options: tempered safety glass (ESG), laminated safety glass (VSG), special glass, frosted glass
• Perimeter glazing beads, mounting brackets for quick installation and fine adjustment

Project-specific structural analysis, connection details, and building physics calculations are the responsibility of the specialist planning and structural engineering firm. In the final step of your configuration, you select your specialist partner.

SF40 – uninsulated:

• Installation depth: 2-track 110 mm, 3-track 165 mm
• Glass thickness: 6–22 mm, max. panel weight 400 kg

SF60 – thermally insulated:

• Installation depth: 2-track 170 mm, 3-track 260 mm
• Glass thickness: 32–34 mm, max. panel weight 800 kg
• Air permeability: Class 4, driving rain resistance: Class 9A, wind load: Class C3/B5

SF80 – highly thermally insulated:

• Installation depth: 210 mm (2-track), 320 mm (3-track)
• Glass thickness: 52–54 mm, max. panel weight 800 kg
• Air permeability: Class 4, driving rain resistance: Class E750, wind load: Class C5

• Sliding windows for terraces
• Transition between living and outdoor areas
• Loggia and balcony glazing
• Summer garden glazing
• Conservatory glazing

Many patio doors are narrow, have wide frames, intrusive thresholds, and take up a lot of space when open. This reduces the view and comfort. Sliding window systems allow for large-area sliding doors with up to 98% glass area and barrier-free thresholds compliant with DIN 18024. Slim profiles provide an almost frameless panoramic view, and U-values ​​starting at 0.75 W/m² K (depending on size and glazing) enhance energy efficiency. This creates a seamless transition between living space and garden.

For conservatories and sunrooms, weather protection, transparency, and thermal insulation should all work together. In combination with SUNFLEX patio roofs, SF40, SF60, and SF80 are ideal for use as conservatory glazing. For sunroom glazing, SF40, as an uninsulated system, is the best and most economical solution.

Tested air, driving rain and wind load classes offer specialist companies the best basis for planning. 

Open loggias and balconies are exposed to wind and weather, while solid interior walls restrict light and flexibility. Sliding window systems allow for large-scale glazing of loggias and balconies. Two- or three-track versions with up to six panels enable particularly wide openings, and low-barrier thresholds enhance comfort. Depending on the location and usage requirements, SF40, SF60, or SF80 models are used.

• Load-bearing structures (the systems do not replace the main load-bearing structure)
• Projects with the highest thermal insulation requirements (e.g., Passive House standard) when using uninsulated SF40
• Very small openings under 1,000 mm wide or 500 mm high

Detailed structural analysis and building physics calculations (e.g., load-bearing capacity, moisture protection) are prepared on a project-specific basis by specialist planners or structural engineers.

As a general guideline: SF40 (uninsulated) is the perfect solution for summer gardens and seasonally used areas. SF60 (thermally insulated) is ideal for patio access and conservatories adjoining heated rooms. If you are planning a year-round living space extension with particularly high energy efficiency requirements, SF80 (highly thermally insulated) is the best choice. Your SUNFLEX specialist partner will discuss your needs and energy requirements and then recommend the appropriate system.

RC2 (Resistance Class 2, formerly WK2) is a European resistance class for burglar-resistant windows and doors according to DIN EN 1627. The standard specifies that the component must withstand an attempted break-in using simple leverage tools such as screwdrivers, pliers, or wedges for at least three minutes. SUNFLEX sliding windows with RC2 features are equipped with multi-point locking mushroom-head bolts, reinforced aluminum profiles, and impact-resistant glazing (P4A). This combination significantly hinders prying open the panels and effectively deters opportunistic burglars.

Statistics show that most burglars give up after three minutes of unsuccessful attempts. Insurance companies and the police recommend RC2 burglar protection for residential buildings in typical neighborhoods.

SF40 is an uninsulated aluminum system with a shallower profile and thinner glass. It is ideal for unheated or seasonal areas. SF60 features thermally insulated profiles with a greater profile depth and thicker glass, resulting in significantly improved thermal insulation. SF80 is even more robust, accommodates high-performance glass, and thus offers the lowest U-values ​​currently available, starting at 0.75 W/m²K, as well as the highest test ratings for driving rain and wind loads. These three systems provide a clear progression in insulation level, ensuring you can find the perfect sliding window for your project.

For the thermally insulated systems SF60 and SF80, Uw values ​​from 0.75 W/m²K are possible, depending on the glass construction, element size, and boundary conditions. These values ​​are calculated specifically for each project, as every glazing configuration and dimension yields different results. Your specialist partner can perform a precise Uw calculation based on the planning sketches and glass specifications. This allows the thermal insulation to be tailored to the building and its energy efficiency goals.

The lower frame structure can be installed flush with the floor, creating a virtually threshold-free solution. This allows the systems to meet the requirements of DIN 18024 for barrier-free construction, for example, for people with reduced mobility or strollers. The exact design of the threshold and drainage is tailored to each project by the specialist company. 

The sliding window systems can reach widths of up to 13,800 mm and heights of up to 4,000 mm, with minimum dimensions of 1,000 mm width and 500 mm height. Depending on the model, 2 to 6 panels are possible. The SF40 allows for panel weights of up to 400 kg, while the SF60 and SF80 allow up to 800 kg per panel. This enables the design of very large glass facades. The maximum dimensions that are practical in each individual case depend on wind loads, glass construction, and fastening system, and are determined during the specialist planning phase.

The integrated follower mechanism connects the sliding panels so that when the operating panel is moved, the other panels are automatically moved along with it. When closing, the subsequent panels are pulled into the final position one after the other, without the need to move each panel individually. This simplifies operation, especially with wide systems and heavy panels. At the same time, the defined movement sequence ensures a consistent seal.

Ball-bearing stainless steel rollers and stainless steel tracks guarantee smooth, virtually frictionless opening and closing of the panels, regardless of their weight.

The number of tracks describes how many parallel guide rails are present in the floor and ceiling profiles. In a two-track system, panels can run on two tracks, and in a three-track system, on three tracks. This allows for different opening configurations and greater opening widths, such as parking multiple panels sideways on one side. The appropriate number of tracks depends on the floor plan and the desired opening width.

Yes, the systems can be designed so that the panels open to the left, to the right, or in both directions. This allows for central openings, asymmetrical layouts, and various operating concepts. The planning process takes into account the main traffic routes, furniture placement, and sight lines. Your specialist partner will develop a suitable opening plan based on these specifications.

The systems are designed so that construction tolerances can be compensated for using mounting shoes and adjustment options. The frames are first roughly aligned, then fine-tuned using mounting shoes and adjusting screws. Even after glazing, the panels can still be readjusted in height and lateral position. This ensures that the smooth operation of the sliding panels is maintained even on uneven surfaces.

Yes, sliding window systems can be used as transparent room dividers, for example between the kitchen and dining area or between living and working zones. Depending on their position relative to the facade and climatic requirements, an uninsulated (SF40) or an insulated one can be used.

The system (SF60/SF80) would be beneficial. The advantage: rooms are visually connected, but remain acoustically and functionally separate. At the same time, the high proportion of glass is maintained, allopanel daylight to flow freely.

For SF60, tests have shown very good air permeability (Class 4), high resistance to driving rain (Class 9A), and strong wind load class C3/B5 – far exceeding the standard of conventional sliding doors. For SF80, top performance has been demonstrated: air permeability (Class 4), resistance to driving rain up to the highest class E750, and wind load class C5, the highest achievable classes for windows and doors. These outstanding values ​​mean that the systems withstand even extreme weather conditions and are ideally suited for highly exposed locations such as sloping sites or coastal regions. The specific classification for a given project is determined based on the planning documents and the installation situation.

SUNFLEX collaborates with qualified specialist partners in Germany and worldwide who support you with planning, consultation, and professional installation. You can quickly find a certified partner near you using the specialist partner search on the SUNFLEX website. These partners are familiar with the technical requirements of the sliding window systems and can advise you on dimensions, insulation values, and available features.