How to make and fit double lumber gates and how to offset and align the hinges allowing the gates to open over raised groun
Introduction and how to hinge and align a gate
It’s a simple enough task to build and fit a standard type garden gate as long as the posts are parallel and the ground is level and even, but what if this is not the case? What if the ground slopes up from the gateway entrance? How can you open a gate if the ground slopes up higher than the bottom of the gate?
Well, there are a few ways to counter this problem, but they might not be suitable in all cases.
Here are a few of the more common solutions:
1. You could fit the gate to open away from the slope, but depending on the make-up and position of the fence and gate, this might not always be possible.
2. You could raise the gate higher off the ground so it can open over the sloping ground. But that’s not much good if you are trying to keep little puppies or other critters locked in. They would all scarper under the bottom of the gate.
3. You could dig out the ground that slopes higher that the bottom of the gate. Not always possible.
4. You could fit a sliding gate. Mmmmmmmmmm, that’s a bit tricky and really needs a complete chapter to go there.
Or you could offset the hinges.
Offset the hinges. That is, align the hinges so that the bottom hinge is not in a vertical line (directly under) the top hinge. The amount of offset determines what the angle or pitch of the gate will be, when opened. When the gate is open, the bottom of the gate angles up, thus enabling the gate to open over raised ground.
We were recently asked to make and fit a gate into an opening in an existing lumber 1800mm (6ft) high fence. The opening was over 2100mm (7ft) wide and in this case double gates would be more practical that one wider gate. The gates had to open inwards and had to be low enough to the ground to keep a little puppy in. The ground sloped up inwards from the gate entrance at right angles to the fence line, as well as sloping along the fence line. We were told that we could not dig out any of the ground that sloped upwards.
Below (Fig.1) is a drawing of how the bottom hinge on the gate can be offset to enable the gate to open over raised ground. The red line in the drawing shows how the top and bottom hinges should be aligned.
How much should the bottom hinge be offset?
About half the degree off plumb, of the degree off level that the incline of the ground is along the fence line. Lost yet?
Okay! Suppose the upward slope of the ground along the fence line is 6 degrees (approximately a rise of 1 in 10), then the bottom hinge should be offset vertically from the top hinge by 3 degrees.
Of course you can always work it out by trial and error, have a couple of people hold the gate in open position and measure the offset.
Note: Sometimes the ground might also be sloping up at right angles to the fence line at a steeper angle than the slope along the fence line. In that case, the bottom hinge will also need to be offset at right angles to the gate. This can be done by adding a block of wood to the gate and fence thus packing the hinge out. You will see how this is done in the following pages.
The drawing below (Fig.2) shows how the gate tilts up when opened.
How to make double gates
Measure for the gates.
Measure the width of the opening between the fence posts where the gates are to go. Deduct approximately 25mm (1″) to allow for the gaps between the two gates and also between each gate and post.
In this case, the opening was 2125mm (85″). We therefore made each gate frame 1050mm (42″) wide. That allowed for an 8mm (1/3″) gap between the two gates and also between each gate and post.
When making the gate frames, plan so that the bottom horizontal frame member will line up with the bottom horizontal fence rail. Refer to Fig.1 in the previous page. This is important on the gate that requires an offset bottom hinge.
The gate frame and hinge offset block.
On even ground, make two rectangular gate frames out of 75×50 (2×3) lumber.
Square and brace the gate frames.
Measure the two opposing diagonals of each gate frame. Adjust each frame until the two opposing diagonal measurements are the same, then the corners of the rectangles will be at right angles.
(In other words, the frames will be square and not be skew-whiff!)
For each gate bracing, lie a piece of 75×50 (2×3) lumber diagonally from corner to corner on the frames. Mark, cut and fix in place with galvanized nails. (See picture).
As shown in the picture, bolt a block of wood to the bottom horizontal frame member. The thickness of the block and the overhang will depend on the required hinge offset. Refer to previous page.
Nail the vertical gate boards to the frames and fix the hinges.
Turn the gate frames over and nail the 150×25 (1×6) vertical fence boards to the frames using 60mm (2 1/2″) flat head galvanized nails. Make The boards flush (even) with the sides of the frames and overhanging top and bottom to suit. The last fence board on each gate might need to be cut (ripped) down the length of the board to fit flush with the edge of the gate frame.
Turn the gate frames back over, and fix the hinges. Make sure the top and bottom hinges are in alignment. See picture.
How to fit double gates
Fix the gates in place
Place the gates in between the two gate posts and sit them on a level board packed up off the ground to the required height (see above picture). Place wedges or packers at the sides of the gates and the middle of the gates so that the gaps between the gates and posts are even, and the gates are ‘jammed in place’.
The gates should be able to stay in position by themselves while the hinges are screwed in place.
Check that the gate opens.
Take out all wedges and packers and see how the gates open.
The gate with the offset hinge should lift above raised ground when opened.
Finishing touches to the gates
Close the gates and add the hardware.
Fit the bolt and gate latch. Note that usually the latch should be put half-way up the gate, but if the gate is to keep little kids in or out, then put the gate latch towards the top of the gate.
Finally, cut a hole in the gate handy to the latch and big enough to put a hand through. This is so the gate can be opened from inside or outside.
Note: There is also another benefit to the “offset hinge”: the gate will always swing shut by itself, merely because of gravity.