When the Glass Is a Door: Setting Oversized Sliding and Lift and Slide Panels
A large sliding door is mostly glass, but it does not behave like a window during installation. Each panel has to end up on a track, at a precise height, lined up with the panels beside it, so it slides cleanly. When those panels are 8 or 12 or 20 feet tall and weigh hundreds of pounds, getting them from the truck to that track becomes its own job.
We set oversized door panels on multi-slide, sliding and lift and slide systems. This post covers what changes when the glass is a door, and what builders can settle before the panels arrive. For large format glass in general, start with our guide to large format glass installation.
Door panels are big, and there are usually several
A window wall might have one oversized piece. A door system usually has a row of them. On the Portland pool house, we set fourteen panels across three door systems totaling more than 80 feet of glass. The largest was a 42-foot multi-slide made of five panels, each 8 feet by 12 feet. Panel weights on that job ran from 250 to 860 pounds.
On a sliding glass installation in San Anselmo, each of three panels measured 5 feet wide by 20 feet tall and weighed 1,200 pounds.
Numbers like these decide the equipment before anything else does. Our fleet covers a wide range: the SmartLift SL 380 lifts up to 840 pounds and is light enough for wood-framed floors, the SL 608 up to 1,320 pounds, and the SL 809 up to 1,800 pounds. Paired MRTA8 manipulators on a crane handle panels of 2,300 pounds and more. The equipment page has the details.
Framed panel or glass on site
Some door panels arrive as finished units, with the glass already in the frame. Others are glazed on site. Ask the door supplier which it will be, because it changes what gets lifted, how much it weighs and when the lift happens.
A framed panel is lifted and set as one piece. In the clip below, one machine outside hands a black-framed sliding door panel to a second machine inside the house, which sets it into the opening on its track.
The path from the truck to the track
Most of the hard problems we see come down to access. A panel that is 12 or 20 feet long cannot turn corners, and it has to travel the whole route at the size it will be installed.
Through the house. On a 975-pound panel in a finished house, the only route was a hallway with tight corners. Framing had to be cut out to make it work. If the glass had been staged before those walls went up, nothing would have needed to come out.
Over the house. At San Anselmo, the house sat between the delivery trailer and the opening, and rain had turned the slope to mud. Each panel went up and over the house on a crane, carried by a hanging manipulator.
Down a level. At the Portland pool house, the doors were one floor below street level. Panels were lifted over the main house and lowered to a machine waiting on the pool deck.
Walk the route with the panel dimensions in hand before the install is scheduled.
The floor under the machine
When the machine has to work inside the house, the floor has to carry it. On the 975-pound job, the floor structure would not carry the larger machine, so it stayed on the trailer and the crew used a smaller machine and a hoist instead. Temporary shoring under the floor would have solved it, and that is simple to plan early and impossible to add once finishes are in.
Staging and sequence
Staging space. At Portland, there was little room at street level, so panels moved straight from their crates into the lifting sequence. Know where crates will sit and how the machines will reach them.
Order of panels. On a multi-panel system, the setting order matters. Agree on it with the door installer before the day.
Who does what. We work alongside the door installer, not in place of them. The installer keeps the product knowledge and the client relationship; we move the pieces that cannot be moved without equipment.
Lift and slide and automated doors
Lift and slide systems are often chosen for large, heavy panels. Lucent's lift and slide systems page explains how they work from the door side.
If the doors will be automated, the automation company belongs in the same schedule. Door Automation Systems covers what automating these doors involves in its guide to automating lift and slide doors.
Plan it before the glass ships
In each of these jobs, the panel sizes and the site conditions could have been known well before install day. A short list to settle early:
panel sizes, weights and count, from the door supplier
whether panels arrive framed or are glazed on site
the route from delivery to the opening, at full panel size
whether the floor can carry the machine, or needs shoring
where crates will be staged
the setting order, agreed with the door installer
You can see more of this work on the San Anselmo project page. To plan a door installation, contact XL Glass Lifting.
