How much runway does a sliding gate need
Two driveways with the same opening width can need runways that differ by several feet, because the tail of a cantilever leaf and the stop of a track slider are not the same length, as the notes at sliding gates georgetown apollo pony describe. On a Georgetown, TX lot the runway is the first thing measured, since a sliding gate with nowhere to slide is only a drawing.
How long is the runway?
The runway for a slide gate is the opening width plus a little for the stop, and for a cantilever gate it is the opening plus the full tail, usually about half the opening again. A twelve foot opening therefore wants a run of about twelve feet for a track gate and about eighteen feet for a cantilever frame. Both figures are measured along the fence line, in a straight path beside the posts.
What gets in the way beside the drive?
Fence panels, a utility box, an air conditioning unit, a mailbox and a tree trunk all steal runway. Roots from live oaks near Lake Georgetown lift the ground and shove a post out of line, so a tree inside the run is a problem even when it clears the leaf on the day. The crew walks the run with a string line and marks everything that sticks out.
How much does slope matter?
The run must be level along its length, or the gate will roll open or shut on its own. On a slope the track or carriage line is cut to follow a true level, and the post heights step to match. A drop of more than a few inches over the run usually means the cantilever design, since the leaf hangs in the air and does not follow the ground. Sun City Texas lots tend to be flat, while lots in the Texas Hill Country edge run steeper.
What if the runway is too short?
A short runway has three fixes: move the fence, switch to a track gate with a shorter frame, or split the leaf into two bi-parting halves that each roll half the distance. A dual swing pair is the last option, and it needs its own clear arc in front of the opening. Each fix changes the post positions, so the choice is made before any concrete goes in.
What gets marked before the crew arrives?
Stakes or paint mark the opening, the full run and the post holes. The operator needs a spot for its power run, and the control box needs a mounting surface out of the sprinkler spray. Underground lines are located before any hole is dug, since the San Gabriel River floodplain and older neighborhoods both hide buried service lines in odd places.