How to Measure Up a Sliding Gate
The width of a Sliding Gate
The distance between fence posts either side of the driveway is the measurement we use for the width of a gate when quoting. If you don't have any fence posts or are replacing your fence then go by where you intend to put posts. The actual width of the finished gate is normally 100mm wider than the measured gate opening so the gate will overlap the fence posts.
The Height of a Sliding Gate
Is measured from where you'd like the top of the gate from the ground for quoting purposes. If the gate is a frame only the height is to the top of the frame not including any palings or battens that extend above the frame. The actual height of the finished gate will be 50mm or so less than this to allow for the wheels and track. This is assuming the driveway is level across and the top and bottom rails of the gate are square, which is rarely the case, normally a driveway has some sort of slope across it and isn't dead straight so measuring the level of the driveway is necessary. This can be done with a simple string line or straight edge placed across the driveway with a spirit level or a laser level and measurements taken from this line to the ground every metre or so. An old school method that works well is some clear flexible tubing with water in it attached to a reference point on one post and the other end is moved about to where ever you want to measure with the water in the tubing being visible and giving you a consistent level.
If the driveway slopes up or down from the direction of the road then the line measured should be along the path the gate will take, which is normally 75mm from the back of the fence posts for a single panel sliding gate with no cladding fitted to the front of the frame. For 2 or 3 panel telescopic sliding gates that stack one in front of the other there will be more than one path, so measurements should be taken along he path of each panel because they may need to be at slightly different heights. If the ground is very uneven then measurements every 500mm may be necessary.
Raking Gates on Driveways that Slope Across
If the driveway has a slope across it with a drop of more than 30mm then the bottom rail of the gate should be raked (RakeB) so if follows the slope of the driveway. If the fences post either side of the driveway are at different heights you should make the top of the gate level with the lowest fence post or if the fence line is following the slope the top of the gate can be raked too (rakeT), either at the same angle as the bottom or at a different angle.
READ MORE about Sliding Gates on Sloping or Uneven Ground
When quoting a gate on this website
The Width and Height sliders on the quote page should be set to the approximate width and height of the gate you are quoting in metres, the RakeT is the rake of the top of the gate and RakeB the rake of the bottom of the gate also in metres being the amount of drop across the driveway or desire drop for the top of the gate. The rake for the top of the gate can be different to the bottom. When raked the height of the gate goes from the highest point so if raked the height of the lower side is the height less the rake. When ordering a gate you will be asked rake or open direction and be given a drawing to approve so there is no confusion. With some styles of gate raking the bottom or top of the gate can effect the quoted price but not always. Sliders that have Gap or Cnt require the Gap between slats or palings to be set or distance set between centres of vertical tubing or battens.
The Space the Gate has to Open
Another important consideration is the amount of space required for the gate to open. If you have less than the measured gate opening + 400mm behind your fence line then you don't have enough room for a single panel sliding gate and need to look into alternatives such as Bi-parting or Telescopic Sliding gates