About a year ago, my family moved into a new house that has stairs. Our youngest son was only about 6 months old at the time, but he was already in the "I want to move around, where can I possibly get, I can't wait to try out the new stairs" phase and it really worried me. I decided to install safety gates at both the top AND bottom of the stairs to make sure he wouldn't "try out" the new stairs until he could traverse them safely.

I had already decided to change the latching method of the gate to be a standard outdoor gate latch (the included latch was a nightmare to open) and already had bought the parts. As I am getting ready to install the first gate, I realize that if I install it as shown in the picture on the box (slightly raised off the floor) it will very quickly be torn out of the wall by my two older boys (ages 4 and 1-1/2 at the time) who are going to try to "ride" it. I quickly realized that I needed each gate to be supported at the end to avoid this catastrophe.

I created this gate mostly based on the parts I had locally available, and the fairly tight budget of a family of 5 (total cost, excluding the gates themselves, was only about $15 per gate). I built these gates over a year ago, but just now got around to posting my first Instructable. This gate has worked wonders for us and has not had any problems.

Step 1: Gather Materials and Tools

The exact sizes of materials for this project will vary based on which safety gate you have, but the accessories per gate should be generally the same:

Adjustable width safety gate (preferably metal) with included hardware/hinges to attach to the wall.
Soft rubber/plastic wheel with swivel caster. The one I used was about a 3" wheel. You will want the material to be non-marking and quiet. The caster also needs to have a threaded rod on the top for attaching through the gate.
(2) Hex nuts that will screw onto the threaded caster.
(1) Gate latch for an exterior gate.
Course-thread screws. The exact number of screws may be different based on how your safety gate attaches to the wall, but (4) of the screws will be needed to attach the gate latch.

As stated above, the exact sizes and tools for this project will vary based on which safety gate you have, but the tools should be generally the same:

If your safety gate did not come with tools, you will need whatever tools are necessary to adjust the width of your gate. Mine required (1) crescent wrench and (2) phillips-head screwdrivers.
Power drill with drill bit slightly larger than the threaded rod on the caster. A smaller bit (1/4") can also be helpful for drilling a pilot hole, but isn't necessary.
Crescent wrench or open-end wrench sized to tighten the nuts onto the caster.
Screwdriver to attached the components to the wall with the screws. A power tool (driver) can be used, but isn't necessary.
Level
Tape measure
Pencil
If possible, another person to hold the gate while you take measurements and mark the wall for attachment locations is helpful, but not necessary. (I know I put this in the tool section, but please don't call them a tool. People tend to not like that for some reason).

Step 2: Adjust the Gate Width

While this step seems fairly self-explanatory, there are a few notes I would like to add:

My gate was able to adjust in a variety of ways. Do the big adjustments first (aligning the bars of the two gate sections), and the small adjustments last (the threaded rods for the top and bottom hinges, and the gate latch threaded rod).
Make sure that the threaded rods for the top and bottom hinges are sticking out the same amount.
There is a threaded rod where the gate latches. This needs to be long enough to fit through the outdoor gate latch.
If there is a threaded rod (or any other hardware) on the bottom corner where the wheel is going to go, take it out.

Step 3: Drill Hole and Attach the Wheel

I decided to place the wheel between the first and second bars toward the end of the gate. Luckily for me, there was a little hole on the side of the gate that helped me center the wheel between the bars. To drill this hole (whether with a pilot bit or the full size bit), turn the gate over, mark your desired hole location, and drill from the bottom. This allows plenty of space for the power drill without the bars getting in the way.

Make sure to drill all the way through this section of the gate. If you take it slow going through the last portion of the gate, the metal won't flare out too much.

Put the threaded portion of the caster through the hole from the bottom of the gate and thread on one of the nuts. Tighten this first nut down all the way to the metal part of the gate, and then thread on the second nut. Tighten the second nut down all the way to the first nut to lock them both in place.

Step 4: Dry-fit the Gate and Mark the Walls

If you have a second person available to help you, now is the time to ask for their help.

Take the wheeled gate to the place you are going to install it. You will also need the hinge hardware pieces that came with the gate to mark on the wall where to install them. Place/hold the gate roughly how it will be installed with the wheel on the ground. Place a level on the gate and adjust the placement until it is level. When the gate is level, take a measurement from the bottom of the gate to the floor, right next to the wheel. Verify that this measurement is the same at the hinge side of the gate. Once you are sure the gate is level, dry-fit the hinge hardware and mark on the wall where the screws will need to be installed. When all the locations are marked, remove the hardware and the gate.

Step 5: Install Hinge Hardware and Gate

Depending on the hinge hardware included with your gate, you may need to have the pieces attached to the gate as you attach them to the wall. With my gate, I was able to attach the lower hinge without the gate, but the upper hinge had to be on the gate prior to screwing it to the wall.

At this point, move the gate along its full range of motion. Verify that the gate moves easily and that the wheel stays touching the ground during the full gate swing. If not, (like mine) you may be able to adjust how much the threaded rod on the top hinge sticks out (I had to make it stick out a little more and then the wheel stayed on the ground).

Step 6: Install Latch

The last step is to install the latch. With the gate rod inside the latch (in the closed gate position), mark the holes on the wall where the latch screws will be installed. Swing the gate open and screw the latch into the wall.

Swing the gate open a few times and verify that everything is working together. That's it!

If your kids are anything like mine, they will have successfully tested the gates ability to hold their weight within the hour.

If you liked my Instructable, please vote for me in the Fix It Contest and/or the First Time Author Contest.