Innovate with Sliding Door and Wall Systems

Reclaim valuable square footage, and help bring daylight and access to views deeper into the floorplan

Jeanette Fitzgerald Pitts

Sliding door and wall systems are more space efficient and offer greater space flexibility than conventional pivot doors and stationary walls. These sliding hardware systems are designed to provide an effective barrier, when necessary, in a fraction of the footprint required by traditional solutions, and then enable occupants to slide the door or wall out of the way when the space division is no longer needed. This approach to doors and walls also offers advantages in satisfying accessibility requirements mandated by the Americans with Disabilities Act (ADA) and green building initiatives. Sliding systems are considered easier to manipulate and maneuver around than swinging doors, and subsequently require less maneuvering clearance than their pivoting counterparts. Sliding glass panels can be used to create a space barrier without blocking daylight from traveling deeper into a space or obstructing views to the outdoors. This is particularly useful when trying to maximize the presence of daylight and views in the interior.

Introducing Sliding Door and Wall Systems

There are many types of sliding door and wall systems now available that offer innovative solutions for designers looking to do more with less space and increase the overall flexibility of any interior.

Straight Sliding Door Systems

Sliding doors can be used in place of hinged or pivot doors, providing the same space division and functionality with a much smaller operational footprint and a large range of available door widths.

The Single Sliding Door

The most basic sliding door system is a single straight-sliding door on a single track. When opened, these doors can be recessed inside the wall to be concealed from view or slide out of the way along the outside wall, remaining visible in both open and closed positions. These space-efficient barriers are an excellent and innovative solution in office and hospitality applications.

Bi-Parting Doors

Bi-parting door systems consist of two door panels on a single track. These systems are opened from the center by pushing the door panels in opposing directions, one to the right and the other to the left. These systems can be operated individually or interconnected for simultaneous operation with a belt and pulley mechanism, which provides a smooth and elegant experience.

Bi-Passing Doors

Bi-passing door systems employ multiple tracks and multiple bi-directional panels. These multifaceted systems are often used to conceal wide storage areas that benefit from multiple access points, such as the libraries found in architectural firms, hotel closets, residential closets, and AV areas in large conference rooms and classrooms.

Telescoping Door Systems

Telescoping door systems are designed to smoothly retract and extend multiple door panels moving in the same direction. Panels in a telescoping door system can be interconnected with a belt and pulley mechanism or with entrainment strips. While the operation of the belt and pulley system creates a very smooth and elegant experience for the operator, there are limits on the quantity, weight, and width of the doors that can be operated this way. The use of entrainment strips can offer similar telescoping panel configurations with fewer limitations on door size and weight, but may result in maintenance issues without proper operation.

Folding Wall Systems

Folding wall systems offer a dynamic alternative to standard stationary walls. They live on a single track with panels that are connected to one another with hinges and fold accordian-style into and out of the space. Each folding wall system may be comprised of up to nine panels. These systems are a good solution for the simple and straightforward task of subdividing one large space into two smaller spaces with one straight wall.

When subdividing a space, there is often a need to go back and forth between the two smaller spaces. A pivot door can be incorporated into a folding wall system, offering easy access to both spaces when the wall is deployed. When not in use, the pivot door can fold up with the rest of the folding system or, depending upon the configuration of the system, it can pivot and park against the wall opposite to the larger stack.

Stacking Wall Systems

Stacking wall systems provide unparalleled flexibility for moveable walls. The panels move independently, into and out of the space, and then stack like dominos at the end of the track when not in use. The tracks can incorporate curves and corners to best fit any desired application. Panels in stacking wall systems can be larger and heavier than the panels in folding wall systems, reaching up to 4 or 5 feet wide, 10 feet tall, and more than 300 pounds in weight. They may also be used for smaller countertop-height systems, which may be handy for security or concealment. Panels within a stacking system can even be different sizes to create a special aesthetic or accommodate a unique design element. These systems can effectively create unique and custom environments within a larger common space, such as a hotel lobby that houses a variety of stores and services, or a restaurant that morphs to accommodate a private event.

System Components

These sliding systems may not be high-tech, but good design and high-quality materials make all the difference in delivering silent, smooth, and easy operation that will last for a very long time.

Panels

The panels are the physical material that create the door or are combined to create the wall that divides the space. Panels can be made of a variety of materials, such as wood, glass, and metal, and some composite materials, including acrylics.

Track

The track used for sliding hardware systems is often either steel or aluminum. These tracks are available in a variety of grades, thicknesses, and finishes. While the type of finish is often mostly aesthetic, the type of the material and the thickness can affect the performance of the track. Thinner tracks can warp over time, while thicker tracks tend to hold their shape more reliably. An anodized aluminum track is one of the most durable types of track available.

Track for sliding hardware systems is also available in several shapes. Three of the most common track shapes are the box shape, the C shape, and the E shape. Advancements in the manufacturing process of the box shape have made this style of track less prone to contamination and have also made it possible to prevent the sliding hardware system from jumping the track. C-shaped track can be bent, allowing panels to traverse along a curved path. E-shaped track also accommodates curved applications and is equipped to handle lateral loads.

Trolley

The trolley is a wheeled carriage that travels along the track and carries the weight of the panel. Today, trolleys often have plastic or plastic-coated wheels for quiet rolling.

It should be noted that there are a variety of trolley styles and shapes, including, but not limited to: two-wheel, four-wheel, and multi-plane (where wheels are placed on both the vertical and horizontal planes) configurations. When selecting the right trolley for a project, it is important to identify whether or not the system will need to travel along a radius or accommodate any lateral movement or sway. Multi-plane trolleys are designed to travel around curves and help control lateral motion, whereas trolleys designed to travel in a straight line may be damaged by lateral movement. It is also important to note that the size of the trolley will change based on the size or weight of the panel it is carrying.

Advancements in both the design of the track and the quality of the trolley wheels have resulted in sliding systems that are smoother, more silent, more durable, and easier to operate than their predecessors. For example, in the past, the trolley would often become misaligned or disengage from the track, causing the sliding door to fall off of the track. Today, the box-shaped track completely encloses the trolley, making misalignment and disengagement impossible, and delivering a reliably smooth sliding experience year after year.

When specifying a sliding system, an important consideration is the length of the top track. Top tracks are available in standard lengths up to about 19 feet. For systems that require longer top tracks, special care should be taken to ensure a precisely connected track. Small gaps in the joints of the track can, and often do, damage the wheel surface of the trolley. Over time, this causes the system to be noisy and, more importantly, can increase the rolling resistance, making the panels harder to open and close. In some cases, the increase in rolling resistance can be substantial enough to cause the system to fail to meet operational force guidelines mandated by the ADA. The ADA requires that hinged doors and sliding doors be able to be operated with a maximum 5-pound force (lbf). Some manufacturers offer top tracks that employ locator pins to provide precise connections. These enhanced tracks will allow trolleys to travel over connections with minimal or no damage.

Suspension

The suspension connects the individual hardware panels to the trolley and can be visible or concealed. Usually, the suspension includes a hanger bolt, which explains why this component is also commonly referred to as the hanger. It is important to ensure that the suspension mount selected is appropriate for the type of panel that is being mounted. Glass panels require different considerations than wood panels and metal panels.

Floor-Mounted or Panel-Mounted Guides

A guide prevents lateral movement, or sway, of the panel. This means that it keeps the panels from swinging back and forth or rattling in response to vibration in the space or airflow. While there are many reasons and many application types that warrant the use of these devices, safety is the most important benefit that these components provide. Guides may be mounted to the floor, an adjacent wall or sliding panel, or directly to the bottom of a sliding panel. Panel-mounted guides are often used to control the motion of very wide and very heavy panels, which can generate larger amounts of lateral movement as they slide. As a general rule, panels sliding further than their own width or larger than 5 feet wide should be controlled by a panel-mounted guide. These guides should also be considered if the height-to-width ratio of the panel is too large to avoid panel sway. The control that guides provide is important, because uncontrolled panel motion can cause damage to the wall, trolley, suspension, or hanger bolt. Damaged components could cause the panel to fall and result in injury.

A panel-mounted guide is comprised of the physical guide mechanism, which is mounted to the bottom of a panel, and a floor-mounted guide channel into which the guide fits.

A floor-mounted guide provides a barrier-free threshold because the guide channel lives in the bottom of the panel and is concealed from view, rather than being mounted to the floor. The physical guide mechanism is either mounted to the floor or an adjacent wall and is concealed by the door or panel.

Doorstop

Doorstops keep the sliding door panels from sliding too far. Door stops may be placed inside the track and mounted on the floor or wall. Whenever possible, it is advisable to place the doorstop as close to the vertical center of the panel as possible or at the top and bottom to stop the panel simultaneously. Inertia will cause the door to rack, or rotate vertically, if the stop is located only at the top. Over time, the racking motion may cause some additional wear and tear on the sliding system.

Benefits of Sliding Hardware Systems

It turns out that the motion of an opening door makes a lot of difference. Whether wood, metal, or glass, opening doors by sliding them along an existing wall or into an existing pocket instead of swinging them open saves a lot of space. Sliding doors require a fraction of the functional footprint required by a hinged door, and this can generate real cost savings as well.

Sliding Doors Save Square Footage

Sliding doors are a more space-effective solution than swinging doors for providing a barrier at a room entrance. The traditional hinge-and-pivot door requires a clear operational footprint that is large enough to accommodate the swing of the door as it moves from open to close. The average size of an interior commercial door in the United States is 36 inches wide by 84 inches tall. In a typical application, where the average-sized door makes a full 180-degree swing, more than 14 square feet (2,016 square inches) must remain clear and unobstructed for the door to work properly. Proper operation of a sliding door requires much less clear space, and that space often falls either along a wall or inside a wall, if the sliding door is recessed. If the average sliding door is 36 inches wide by 84 inches tall by 1.75 inches thick, it requires a space only that size be extended along the track.

Consider the layout of an average 10 foot by 15 foot private office with a pivot door. The first 3 feet of the office space are used, almost exclusively, to allow the door to open and shut, leaving a 10 foot by 12 foot space to fill with office furniture and dedicate to office work. If the pivot door is replaced with a sliding door, the exact same office furniture and functionality can be provided in an office that is actually 10 feet by 12 feet. Designers can provide clients with essentially the same office in a space that is 20 percent smaller.

Associated Cost Savings

Space is one of the most valuable assets in the built environment. Eliminating a swinging door from the floorplan can return a lot of square footage back into active duty and enable designers to do more with a smaller amount of space. This flexibility offers a real value. LoopNet™, a website that tracks commercial real estate trends in Chicago, identifies the current median price for office space as $139 per square foot. At that price, the 20 percent smaller office footprint enables a designer to save $4,170 per office.

Reduced Maneuvering Clearance Required by ADA

Sliding doors also save space because the ADA requires a smaller clearance for maneuvering in front of a sliding door when compared with the clearance required in front of a swinging door. Section 404.2.4 of the ADAAG defines the acceptable maneuvering clearances for different types of doors. Clearances for swinging doors and gates are defined in terms of the approach, whether it is parallel or perpendicular to the door, and whether a person is maneuvering around the pull or push side of the door. The maneuvering clearances required by the ADA in front of sliding doors is nearly the same as the maneuvering clearance required when there is no door on an opening.

Access Daylight and Views Deeper in a Space with Glass Panels and Moveable Walls

Incorporating soft, glare-free daylight and outdoor views into the built environment has been proven to have a powerful effect on the people and energy use in the space. When people have access to daylight and outdoor views from inside a building, studies have shown an increase in productivity and an improvement in mood. They also learn and heal faster. With regard to systems efficiency, dimming electric lights or turning them off when sufficient daylight is available has been credited with reducing the energy used by the lighting system by 20 to 80 percent.

The potential upsides to occupant well-being and energy efficiency have motivated many designers and building owners to demand more daylight and access to views deeper into the floorplate.

Even the latest version of the green building rating system, Leadership in Energy and Environmental Design (LEED™) v4 awards points for achieving a certain degree of daylight penetration and view in most of the regularly occupied spaces in a building.

Daylight penetration in the interior is affected by many design decisions. Fenestration choices on the building envelope, such as the window-to-wall ratio, building orientation, type of glass, and the daylight control mechanism, all affect the amount of daylight allowed to pass into the interior space. Interior design decisions about the layout of the floorplan, furnishings, and finishes determine how deeply daylight is allowed to travel once inside.

In an effort to bring daylight deeper into the space and provide exposure and views to a greater number of building occupants, designers are trading in those perimeter private offices with walkways and communal areas. Interior palettes that used to boast dark and rich colors have been replaced with lighter neutrals that do a better job of reflecting daylight, instead of absorbing it. Space partitions are being lowered, and solid doors and walls that stop daylight in its tracks, and obstruct views, are turning into glass and sliding out of the way when not needed, minimizing the obstacles that prevent daylight from traveling deeper into the interior and block line-of-sight to the outdoor environment.

Using Sliding Glass Panels at Fortis

The headquarters of Fortis Commercial Construction in Dallas, Texas, is a 3,000-square-foot office in a high-rise with floor-to-ceiling windows on south and east-facing exposures that offer views of both tree-filled residential areas and the bustling Dallas cityscape, which includes the Winspear Opera House, the Federal Reserve building, and the giant Ferris wheel at the Dallas fairgrounds.

Sliding glass door systems are used as the doors for the perimeter private offices and the perimeter conference room. The glass sliding system was selected because it satisfied two of the primary objectives of the space: make the most out of every square foot, without chopping up the floorplan and making the space feel small, and maximize the access to the great Dallas view available throughout the space.

“Using sliding glass panels kept the entire space feeling open and bright, and lets everyone enjoy the views from almost every corner of the space,” explains Sharon Vaughan, principal.

Tips for Selecting Glass Panels

Using glass panels in sliding door and wall systems enables daylight to travel deeper into the interior spaces. There are certain glass-specific considerations that must be made to select a glass sliding hardware system that is safe for the project space and able to satisfy the aesthetic preferences of the design team.

Machined Glass Panels Versus Non-Machined Glass Panels

If glass is selected as the panel material for a sliding hardware system, the designer or design team will need to choose between installing a machined glass panel or a non-machined glass panel. There are essentially two ways to mount a glass panel into an architectural sliding system. One is to drill holes or cutouts into the glass—a process called machining, which enables the mounting mechanism to be inserted through the glass panel and attached to the system. The other way to affix the glass panel to a sliding system is to select a clamp-style mounting, where the mounting hardware clamps onto the glass, holding it in place.

While the clamp will mount a glass panel that has not been machined, or non-machined glass, there is a risk of the glass slipping in the clamp, as the prolonged movement of the system combined with the weight of the panel can cause the glass panel to shift and vibrate. With machined glass, the mounting hardware does not physically clamp onto the glass, but instead attaches through the glass, via the cutouts that have been machined into the glass panel.

Glass Panel Mounting Options

When specifying a glass panel for a door or wall system, transparency is often an aesthetic objective of the design team. The type of mounting will impact whether or not the mounting hardware is fully concealed or visible and to what degree. There are five mounting options for glass panels.

Frameless

In a frameless mounting, the hardware is fully concealed in the track, preserving the transparency provided by the glass system. This mounting style may require that the glass panel be machined and can be used with either fully tempered or laminated glass.

Patch Fitting

The patch fitting mounting style requires machined glass and provides minimal hardware exposure. This mounting option is often the most economical and can be applied to both fully tempered and laminated glass.

Suspension Profile

In a suspension profile mounting, the suspension hardware is concealed in the cover profile, essentially hidden from view. The mounting style may require machined glass and can be used with either fully tempered or laminated glass, although some restrictions apply.

Framed

The framed mounting style frames the glass panel on all four sides and provides rigidity for tall glass panel applications. This style does not require machined glass.

Friction Clamp

A friction clamp mounts glass panels without requiring that they undergo the machining process. This mounting option may not be suitable for panels that weigh more than 220 pounds and is often not recommended for use with laminated glass.

Greater Design Freedom

Sliding door and wall systems are tools that enable designers to create space layouts that were not possible with hinged door solutions. They deliver unparalleled flexibility in multipurpose spaces, and offer a unique opportunity to camouflage and conceal spaces or equipment when they need to be temporarily out of sight. As an alternative to the standard pivot door and stationary wall, these systems also enhance the experience in a space by giving owners and occupants something unexpected. Designers will experience a new degree of design freedom as they unhinge their spaces and creative visions.

Create Larger Space Openings

The ICC International Building Code® (IBC) caps the width of a swinging door that can be used in a means of egress at 48 inches. For this reason, and some other limitations on available material sizes, most door manufacturers commonly produce swinging doors only up to 48 inches wide as part of their standard product offering. This generally limits the width of most hinged openings to 48 inches for one door or 96 inches (8 feet) for two doors, without subdividing the space with the physical obstructions of additional door frames.

As sliding systems require no door jambs, designers can create wider openings with commonly available door widths by using multiple sliding panels.

Dynamic Space Division

Sliding doors and wall systems are an innovative solution that can enable designers to maximize the flexibility and adaptability built into a space. An open office space can be transformed to accommodate a visiting guest or provide a temporary conference room for a group discussion by simply sliding a wall system into place. Restaurants can keep the floorplan open to seat as many general diners as possible and then enclose a section to provide a more private group dining experience, when booked. Moveable wall systems easily subdivide a large hospitality space into smaller, more intimate areas with a customized aesthetic and then smoothly slide out of the way to accommodate a bigger event.

Designers are also integrating sliding wall systems into residential spaces in large urban cities where space is at a premium. A sliding wall can temporarily partition off the bedroom or create a more formal dining room when entertaining in these spaces.

Concealment

Beyond using a sliding door or wall to subdivide a larger space into smaller, functional areas, these systems can also conceal areas or equipment from the visual space. A good fit for both commercial and residential applications, these systems can hide away kitchenettes or laundry areas when not in use.

Specifying Sliding Door and Wall Systems

The best place to begin when looking to incorporate sliding door or wall systems into a space is with a good specification. Here are some tips for specifying a sliding hardware system that will meet project needs and work smoothly and reliably for many, many years.

Specifying Single-Panel Straight Doors

The most critical aspect of any sliding hardware system, from a single-panel door to the most elaborate stacking wall, to identify during specification is the weight of the panels that will be used. Every sliding system is rated to be able to manage a specific amount of panel weight. Selecting the right system for a project depends upon selecting a system that can support the exact type of door that is going to be used. Exceeding the weight capacity for which the system is rated can result in damage to the trolley, the track, or the suspension, impeding performance, and may even cause system failure.

In order to determine the exact measurements and weight of the door panel that will be used in a single-panel door application, it is important to start by identifying the size of the opening, in both height and width, and selecting the panel material, usually glass, wood, or metal.

Now it is time to determine the necessary width of the door panel. One significant difference between selecting a pivot door and a sliding door is the need to consider overlaps. While pivot doors are designed to fit snugly into the opening, sliding doors need to overlap the opening to prevent sightlines into the space when the door is closed and, in some cases, to conceal the door guide. To determine the size and number of the necessary overlaps, the decision must be made on how the door is going to be applied in the space. Designers will need to decide whether the door is going to reside in a pocket and be pulled flush to the edge of the wall when closed, requiring that the door be wide enough to provide overlap on only one side of the opening, the side with the recessed pocket, or if the door is going to slide along the outside of the wall, in a barn door style application, in which case the door will need to provide overlap on both sides of the opening. The width of a single-panel door is determined by the opening width plus the amount of overlap necessary. A typical 36-inch-wide opening may require a sliding door that is 40 inches wide.

Once the size of the door is determined, designers can find out how much a panel of that size weighs in the desired panel material. A sliding hardware system with an appropriate capacity can then be selected, and designers can choose from available track mount and suspension mounting options. As a rule of thumb, designers specify the track length as two times the width of the door panel.

Specifying a Telescoping Door

When specifying a telescoping system, where the panels extend and retract from one side, the same emphasis is placed on identifying the weight of the panels in order to select an appropriate sliding hardware system. It is important to remember that in a telescoping system, the panels must provide an overlap at each of the panels, as well as an overlap with the two sides of the opening. A 6-foot opening that will be covered with two telescoping doors will not use two 3-foot doors, instead it may require two doors that are each 40 inches wide.

Specifying a Folding Wall

There are two types of folding systems: a center-hung folding system and an edge-hung folding system. When specifying a folding system, the first decision to make is which of these two systems is the best fit. In a center-hung panel system, the trolley is mounted mid-panel. This creates a very stable panel system that will not shift or sway significantly as it opens and closes. For this reason, it may not require a guide, meaning that there is no need for a continuous floor-mounted guide channel throughout the space. In an edge-hung folding system, the trolleys are mounted at the edge of the panel. Because of gravity, the panels that are edge-hung will want to twist as they open and close, so edge-hung systems do require a guide and a small guide channel in the floor that will be visible even when the system is parked against the wall.

In terms of aesthetics, edge-hung panels offer better symmetry because all of the panels are the same size. This is not the case with center-hung folding systems because the first panel must be narrower than the rest of the panels.

Depending upon the application, the clearance area for the wall when it’s parked may or may not be an issue. When center-hung folding systems stack, the panels are centered on the track, with half of the panel width extending either side of it. When edge-hung folding systems stack, the entire panel extends to one side of the track. If the panel system is being used to divide one large space into two smaller spaces, the clearance of the stacked panels probably doesn’t matter. In scenarios where these panel systems are used to define a boundary, like a mall store front, the difference in clearances becomes a much more important feature because half of the parked center-hung panel system will hang out into the hallway or common area.

Once the decision has been made between a center-hung and edge-hung folding system, the specific panels and hardware are ready to be specified. The folding system is specified in bi-fold sets, meaning that each specified hardware set is for a pair of panels that will fold onto each other. The set adjacent to the wall is the first, basic set. Continue adding pairs of panels and the associated hardware until the necessary wall length has been reached to fill in the opening. Then the pivot doors can be added either onto the folded stack or on the opposite side adjacent to the wall. Next select the top track, guides, bottom guide channel, if required, and the hinges.

Specifying a Stacking Wall

Stacking systems provide unparalleled variability in the types of configurations into which it can be designed. These panels can move back and forth independently, and the track can incorporate curves and corners. When specifying a stacking system, the best place to start is to determine where the wall is needed, map out the configuration of the track, and identify the total size of the opening. Pivot doors can also be included in the stacking wall, providing points of egress where desired or required by code.

Another important decision is to determine how the panels should be parked and whether or not they will be visible or hidden when not in use. Panels can be parked parallel or perpendicular to the track, depending upon space constraints of the application. If the parking area will be exposed, there are ways to make the parking area track more aesthetically pleasing. The interior section of the track can be concealed so that the back of the track and the trolleys are not visible.

The wasted space required by hinges and swinging doors is an unnecessary opportunity cost in today’s built environment, as is the rigidity delivered by permanent wall structures in many interior spaces. Consider specifying a sliding door or wall system into any project where space efficiency and flexibility are primary design objectives. The opportunity for significant returns in square footage and value-driven space use is, literally, at the door.

Hawa Americas Inc. Hawa is renowned internationally as a leading manufacturer of sliding hardware systems. The Swiss company has a solution for virtually any requirement, any material and any door weight, from sliding doors for buildings to sliding shutters and highly complex sliding wall systems. http://www.hawa.com/en/home/