A regular sliding door uses a static rail fixed at the bottom of the outer frame. The door is supported by small rollers under the vent which move along the bottom rail. To maintain sufficient water and air tightness, sliding doors have very little clearance between the rail and the vent, creating significant friction and rubbing of the seals, even on brand-new doors. Over time, as debris and corrosion reduce the clearance even further and the bearings on the rollers wear out, sliding doors become harder and harder to open, especially on larger elements. You have probably noticed it yourself on older slider doors.
Lift and slide doors avoid the issues of regular sliding doors by utilizing a mechanism that lifts up the door before sliding. It can be used with nearly limitless sliding door designs, from conventional two-panel setups to multi-panel, corner-less configurations spanning the width of a house or building.
As you turn the handle down, the vent is lifted by a pulley system. The vent is fully released from its seals and has more clearance from the bottom rail. The door can now slide at the push of a finger. Move the handle back to the original position and the rail is lowered, sitting the vent back down on the bottom of the frame for maximum air and water tightness. In the closed position, the rail is completely protected from debris and corrosion.
Better water and air tightness, reduced wear and tear
Since regular sliding doors cannot disengage their seals when the doors are opened and closed, sliding door designs attempt to balance the need for air/watertight seals with the need to minimize the friction of those seals while operating the door. Ultimately, sliding doors do not achieve either of these requirements well. In fact, sliding doors quickly become difficult to operate and their water/air tightness quickly deteriorates with each use.
Improved forced entry resistance
When a lift and slide door is shut, and the handle is moved into the closed position, not only are the locking mechanisms engaged, but the full weight of the vent is set down onto the frame. Intruders would not only need to create enough leverage to break the multipoint locking mechanism, but also move the weight of the vent. Considering that vents on larger lift and slide doors are easily 300 to 800 pounds, it adds a significant amount of security. In addition, even if the vent is left slightly open for ventilation, it can not be just pushed open as long as the handle can’t be moved from the outside.