While sliding doors predate World War II, they exploded onto the building scene in the 1950’s and 60’s. They became the staple of the ranch-style tract house and a regular component of apartments and hotel/motel chains, and of course, we can’t forget about mobile homes. Their popularity grew because they offered the value proposition of lots of light, egress, and low cost. The initial offerings were mostly aluminum framed (without thermal breaks) and single panes of glass. As was common during that period, tempered or laminated safety glass was not required, although in 1977 safety glass became mandatory. The talented singer, Della Reese, was almost decapitated after absentmindedly walking through the non-tempered glass of a sliding door in 1970. Fortunately, she lived to sing again.
Sliding doors were improved in the 80’s and 90’s through the addition of thermally broken frames and insulated glass. As the glass areas of the sliding panels grew larger to allow for more light and vision, they also got heavier which made them more difficult to move. European (spelled German) hardware was developed to create lift and slide doors which incorporate long handles that give mechanical advantage to complicated hardware that lifts the door to lower rollers and break the weatherstrip contact to eliminate the friction and make the doors easier (but not easy) to operate. Some sliding door manufacturers have opted for larger rollers that more easily roll than tiny ones, but debris in the tracks can still be a problem.
With the sliding operation, the door panel does not offer any interference to furniture or other objects that would normally have to be kept away from the swing path of a door. This is considered by some to be an advantage. As with all advantages, it comes with a tradeoff. Sliding panels require different tracks for each panel to telescope or stack over one another to make for the fullest opening. Each of these operating tracks is on a different visual plane so when you look at them from the outside during the daytime there is not a consistent reflection pattern, which isn’t as clean as a fixed glass wall. The ability to open usually trumps the aesthetic objection of the critical eye.
Most of the doors that we encounter during our lives are swing doors. The action of grabbing the handle, twisting it, and then pushing or pulling the free end of the door is second nature to us and requires no thought at all. With outswing doors, there is a fluidity to the motion that means we don’t even miss a beat when moving through the opening. Sliding doors, on the other hand, are less often encountered and require a stop action when encountering the door pulling the panel to the side and passing through. The closing motion requires stopping on the opposite side turning around 180 degrees and pulling the door closed. Some people get annoyed with this operation and opt to replace the “builder’s special” with French or folding doors when they have a chance.
Sliding doors can be used in very wide openings by adding more than two tracks, but the thickness quickly increases to be deeper than the popular 2×6 construction walls of well-insulated walls and need to have special build-outs to accommodate them. The stacking panels can also be hidden when fully opened by placing the “stack” of panels within the wall itself by creating a pocket. This leads to a cool look, but repairs and adjustment if required in the future often lead to ripping out a wall which is more than inconvenient.
Finally, there are locking and leaking issues to address or at least be mindful of. Modern sliding doors have gotten better at keeping air and water out, but usually at the cost of high sill dams and extra force needed to operate. Early sliding doors offered almost no security from intruders at all since they merely needed to be lifted to dislodge the panels. Again, better door design is available and can make this problem go away.
We don’t make 2Fold® sliding doors because we believe that we don’t have a clever solution to the challenges that they present. Until we are struck by lightning, we’ll stick to the folding, single and French doors that we make which are innovative and unique.