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When planning for accessibility, people usually think first of walk-in showers, grab bars, or ramps. Doors often take a back seat—even though they play a crucial role in everyday life in determining whether people can enter a building or a room independently.
This is particularly evident in small rooms. Bathrooms, in particular, are often cramped in many apartments and further cluttered by a washing machine, bathtub, or furniture. A traditional door (referred to in the interview as a “swing door”) requires a lot of space to swing open—precisely where people using a walker or wheelchair often need room to maneuver in order to even reach the doorknob and open the door.
We speak with Peter Bischoff, General Manager of Küffner: a German family-owned company that developed the space-saving, accessible door more than 30 years ago. In this interview, he explains how a solution designed for people in wheelchairs evolved into a multi-award-winning accessible door system—and what really matters when choosing the right door.
SBC: Mr. Bischoff, Küffner is actually known for aluminum door frames—that is, a door frame made of aluminum into which a door is hung. So how did the accessible door come about?
Bischoff: That’s right; our story actually begins at a different point. Our company founder, Reinhold Küffner—who is now 82 years old—had the idea 54 years ago to develop a corrosion-resistant frame for wet areas. At that time, swimming pool construction was booming, and the first attempts using waterproof-glued particleboard covered with aluminum swelled up due to the moisture. This led to the idea of manufacturing the frame out of pure aluminum instead. That was the cornerstone of the company’s entire success—and the foundation upon which the space-saving door was later developed.
Incidentally, our aluminum door frames and other products from our company can also be found in the German Bundestag and in the newly renovated Austrian Parliament.
We introduced the space-saving door to the market more than 30 years ago. At that time, the term “accessibility” had not yet become established, which is why our product was originally called the “door for people with disabilities and space-saving door.” An important milestone came in 2002 with the German Disability Equality Act, which clearly defined the concept of accessibility in law for the first time.
Our fold-and-turn door was honored as early as 1994 with the Red Dot from the Design Zentrum Essen, the predecessor of today’s red dot design award. And in 2004, it was the first door ever to be certified as “DIN-certified barrier-free.” We don’t just claim that our space-saving door actually requires the least amount of clearance for wheelchairs and walkers—we had it scientifically tested by the IHD in Dresden (Note: Institute for Wood Technology). There, a room was equipped with a hinged door, a sliding door, and a space-saving door; it was filmed from above and tested with real 80-year-old walker and wheelchair users. The space-saving door performed the best in the test.
By the way, in addition to the space-saving door, we’ve developed two other accessible door solutions: a finger-protection door for preschools, which we manufacture for 200 to 250 daycare centers every year. And the so-called “Klöntür”—a type of barn door with a closed lower section and an open upper section—which we developed specifically for dementia care facilities.
SBC: When most people think of an accessible door, the first thing that comes to mind is the door width—so that someone using a walker or wheelchair can get through. Are there any other aspects to consider?
Bischoff: The width of a door is undoubtedly important—the standard specifies 90 centimeters for public spaces and 85 cm for private spaces. But in the end, it’s not the standard that matters, but the person who is supposed to enjoy that comfort. In most cases, 80 or even 75 centimeters is sufficient. However, the passage width alone does not make a door accessible.
In practice, the main concern is how comfortably and safely a door can be operated in everyday life. Equally important are low operating forces and intuitive operation. An accessible door should be easy to open and close and should not require complicated movements. Ultimately, it should function equally comfortably for all users—regardless of age or physical ability.
When it comes to the other criteria, safety naturally plays a role. Finger protection or an integrated emergency-opening feature are particularly important in care facilities or accessible restrooms. The door must also be able to be opened from the outside, for example, if someone falls behind it and needs help.
At the same time, accessibility today must not conflict with architecture and design. Building owners and architects expect solutions that are functionally sound and, at the same time, blend harmoniously into the building’s design.
Accessibility therefore always results from the interplay of various factors: sufficient clearance width, minimal space requirements when opening, ergonomic usability, safety, and thoughtful integration into the building. Only when all these aspects are taken into account can a door truly meet the demands of everyday life.
SBC: Who is your space-saving door particularly suitable for?
Bischoff: Space-saving doors are particularly useful wherever accessibility and limited space intersect—and where people want to open doors on their own and, for example, use restrooms without assistance.
A key consideration is the door’s swing range. Especially in small rooms or hallways—for example, outside accessible restrooms in care facilities or apartments—there is often not enough space to fully open a conventional hinged door. For people in wheelchairs or using walkers, this often means they can no longer reach the doorknob when opening or closing the door. They then have to maneuver laboriously—moving forward and backward. Or they end up sitting on the toilet with the door open because they can’t close it.
This is exactly where space-saving doors come in: Thanks to their special folding mechanism, the door handle remains within reach throughout the entire opening process, while at the same time requiring significantly less space in front of or behind the door.
By the way, it’s often worth taking a second look in your home as well: If you’re planning a major bathroom renovation that involves retiling the wall anyway, it costs hardly anything extra to widen the wall opening by 10 to 12 centimeters right away—provided it’s not a load-bearing wall.
Incidentally, in many cases, a renovation can achieve more than one might initially think. This applies not only to private apartments but also to nursing homes and senior living facilities. A good example is the renovation of the Lore-Malsch nursing home near Munich-Riedering: As in many older facilities, the bathrooms were designed as simple built-in units. These bathrooms are often located inside the hallway so that the window area in the resident’s room remains unobstructed.
When using our space-saving doors, it’s often possible to move the bathroom walls about half a meter toward the hallway. Because only one-third of the door panel swings into the hallway when opened, it takes up significantly less space there than a traditional hinged door. This has allowed us to enlarge the bathroom in some floor plans without unduly restricting the functionality of the hallway. As a result, there is more space to move around in the bathrooms—ideally enough to make them barrier-free in accordance with standards. This is particularly important when not only one person is acting independently, but a caregiver is also present to assist with washing, showering, or transferring.
So you gain in two ways: more space to move around in the bathroom and, at the same time, better usability of the hallway area.
Our clients include senior living facilities, assisted living facilities, hospitals, and rehabilitation clinics. It’s important to take these different target groups into account: In retirement homes, assisted living facilities, or rehabilitation clinics, people are still able to move around independently, usually with a walker—and that’s exactly what the space-saving door is designed for. In nursing homes, on the other hand, doors are often operated by staff, and residents are either being pushed in a wheelchair or are lying in bed. In these cases, we sometimes use large sliding doors wide enough to accommodate an entire nursing bed.
Our space-saving doors are also used in public spaces—from city halls and churches to highway rest stops—and increasingly in residential construction.
SBC: Since you brought up sliding doors: They’re often considered a space-saving alternative—what’s your take on that?
Bischoff: For many users, sliding doors feel ergonomically unfamiliar. You stand in front of them and have to exert force to move the door panel to the side—pulling and pushing don’t work. When trying to move a sliding door to the side, the way you have to apply force is so awkward that a person who needs assistance could fall.
By the way, this isn’t just a matter of physical strength, but also of understanding: People first have to figure out how a new door works. The beauty of the space-saving door is that it operates exactly like a traditional hinged door—the same door handle, the same motion that many people have been performing automatically for decades. That’s exactly what’s missing with a sliding door: People who’ve used traditional doors their whole lives find themselves standing in front of one with their walker and have to learn a completely new sequence of movements.
There are significantly more people who use a walker or other walking aid than there are people who use a wheelchair. These individuals, in particular, often have only one hand free and are not steady enough to slide a sliding door open. Another issue is that a sliding door requires sufficient space on the side. Often, a sliding door does not close properly, meaning it does not seal adequately.
SBC: How much work does it take to replace an existing door with a space-saving door?
Bischoff: Our design allows for retrofitting into existing door frames. The only requirement is that the folded door panel reduces the clearance by about 85 millimeters. Depending on the existing width of the door frame opening, this may pose a limitation—at least 85 centimeters is desirable, but in most cases, 80 or 75 centimeters is sufficient. If the door opening is too small, the wall opening must be redone.
Our doors require professional installation; for residential renovations, the best people to contact are usually carpentry shops, door specialists, or building components specialists. If door openings need to be widened, relocated, or structurally modified, interior finishers, drywall contractors, or general contractors may also be needed.
SBC: You also mentioned safety, for example in relation to door closers. What’s the problem there?
Bischoff: Door closers are required for fire and smoke protection doors for good reason—because these doors must always remain closed in the event of a fire. The standard even allows them for accessible doors, up to a certain closing force. What many people don’t realize is that these closers operate hydraulically, using oil.
At 38 degrees in the summer, the oil becomes thin, and the door literally slams shut. At 10 degrees in the winter, that same oil becomes thick, and that same door barely opens. Ask a wheelchair user if they can open a door on their own—you’ll just get a shake of the head. For independent use—outside of a fire emergency—there are therefore so-called free-swing door closers. These door closers only release the spring that closes the door once the smoke detector is triggered. Until then, the doors can be opened without resistance.
SBC: What advice would you give to a senior citizen planning an accessible home renovation?
Bischoff: Don’t wait until it becomes absolutely necessary. If you plan early, you’ll have significantly more options and can take your time deciding how to design your home so that it continues to meet your needs in the future. Renovating under time pressure is usually more tedious and ends up being more expensive. With time and a calm approach, modernizing can even be fun.
The goal here is not to remodel the home to make it “care-friendly,” but to maintain living comfort and independence over the long term. Many accessibility features enhance comfort for people of all ages—threshold-free transitions, spacious areas for movement, or doors that are easy to operate even with limited mobility. Doors, in particular, are often underestimated during the planning phase, yet they play a key role in determining whether we can move freely and safely within our own homes on a daily basis.
And take a holistic view of the renovation: Accessibility isn’t achieved through individual products, but through the interplay of architecture, function, and practicality for everyday life. Ultimately, it’s about more than just standards—it’s about being able to live independently in your own home for as long as possible.
Thank you for the interview!
Peter Bischoff is the General Manager of Küffner Aluzargen GmbH & Co. OHG, a German family-owned company that launched the first DIN-certified accessible door more than 30 years ago. The Küffner space-saving door has been honored with the red dot design award as well as Universal Design Awards. For our international readers: These solutions are also available worldwide. Learn more about space-saving and accessible doors at kueffner.de
Author: Anja Herberth
Chefredakteurin
