Making an Automatic Sliding Gate

Sliding gates can be quite useful for closing in your yard. In my case a garage door would have cost about the same however limited the usable space. After looking around many places offer prefabricated gates however they seemed a bit more expensive or you would have to pick up the whole gate once it has been made. Given my gate was 4.5 meters wide and 1.5 meters high, I would have had to likely hire a truck and drive a fair distance. Not to mention the gate would have been custom made since i couldnt find anyone who reasonably flat packed that size. Though this may be a viable option for yourself if you want to save on time, effort and to get the desired finish.

After some research I thought i may be able to pull this off. As a general handy kind of person but not too much experience in cutting, welding and general construction - it seemed like a reasonable project to try and tackle.

PLANNING

These are the guides (Jackal Fencing | EasyGate | BMGI | AutomaticGateSolutions ) I read which were very handy on the do's and dont's for sliding gate consutruction and installation. Its recommended to have a read if you're looking to make a start. It definitely helped in preparing for what would be required for the construction and installation.

CONSTRUCTION

After measuring up the following was aquired to make the frame and support posts from a local metal supplier. I found Scott's Metals quite handy for finding metal products and prices for estimation. Atleast when you go into your local supplier you vaguely sound like you know what you're talking about.

1. 100x100x2 SHS Galvanised steel (2x2.2m)
2. 50x50x2 - SHS Galvanised steel (1x4.5 and 2x1.58m)
3. 100x50x2 RHS Galvanised steel (1 x  4.5m)
4. 25x25x3 angle - (2 x 4.4m)

The slats came down to a choice of Merbau decking or hardwood fence. The total coverage including spacing was 6.732m2. I gave the hardwood fence a go and just sanded it back and clear varnished it. I figure i can always swap them out in the future if i dont like how it weathers. Another consideration was aluminium slats.

Gate weight was also important to calculate since it would provide the specifications for the solar motor and other weight calulations. Not to mention how to maneuver it into place.

Wood:
23kg/m2 x 6.732 (1.53 x 4.4) = 154.836kg

Steel:
50 x 50 x 2mm (2x1530, 1 x 4500)= 2.93kg/m = 22.1508kgs
100 x 50 x 2mm (1 x 4500) = 4.50kg/m = 20.25kgs
25 x 25 x 3mm (4400) = 1.89kg/m = 8.316kgs

TOTAL = 205.5528 kgs

Etch primer and black spray paint was used to finsh the frame and support posts. The primer was just applied using a roller brush. I considered powercoating the whole thing however i would have needed to transport it to and from.

For the Solar Gate Opener I used the weight and gate dimentions to work out a suitable unit. I managed to pick one up as a complete kit which seemed to work well. What i liked about this unit (apart from everything came together) was that it supported inputs of 24v DC/AC and 240v. This meant I could run additional low voltage power without the need of an electrican via a trench if the battery system didnt work as well as I wanted. Its been working perfectly for the last few months so fingers crossed.

Next I just needed a roller kit which allows the gate to slide manually across a track. Only issue with the one I ordered was it didnt come with enough track fasteners which I ordered separately from tigerlink.

Before moving the gate frame into place I had to put down a footing. This was after I cemented the 100x100 posts into place. For the specifications I just used what was in the guides posted above. Trench mesh or reinforcing steel helps with cracking and ensures the track stays straight. I made a conduit hole in the footing for where the additional power to the motor could be run in the event i needed it.

      

A rough sequence of construction was as follows:

1. measure up everything
2. dig footing and post holes
3. cement posts into place
4. complete track footing
5. weld up gate
6. attach rollers to gate
7. paint gate
8. prepare wooden slats (pre-drill screw holes, sand and varnish)

INSTALLATION

Once all the construction was finished the gate was installed in the following order. See guides for more detailed information to do some of these steps.

1. attach track to footing and drive way
2. move frame into place
3. attach support rollers, catch and stoppers
4. install solar kit and motor 
5. adjust gear tracks accordingly
6. attach limit switch striker plates
7. screw slats to frame

The footing and sliding track was a bit tricky during installation since the drive way has a bit of a hump in the middle. I ended up having to cut into the driveway and had the track on a slight slope. While there is no issue with this the trick was keeping the slope straight so that when the gate is sliding it doesnt touch at any point. This is covered a bit more in the lessons learnt section.

The automatic motor needed a support frame to get it to the desired height. This frame was dynabolted into the concrete footing

A good tip is to ensure that the gate moves freely without having the motor move it before you program the electronics. Once the motor is fixed to the ground you can adjust the gear tracks to the right height/position and manually release the motor so it has good connectivity between the tracks and the teeth for the whole time it is moving. Surprisingly this didnt not need to be as perfect as I thought it may to get it working well however the better you get it the less likely it will have issues in the future. 

A video of the final product in full swing can be found here :)

COST

Roller Gate Kit - $253
Steel: $240
Paint: $5
Additionally (counter sunk, respirator) = $10
Primer $29
Rio $10
Solar gate opener $360
Hardwood fence pailings (44) $88
1L varnish and 200 gal 22mm screws $60
26 x Sliding Gate Track Fasteners Zipfix 40mm x 6mm $16.80

TOTAL: $1071.80

LESSONS

Things I would do differently that come to mind are as follows:

Gate Construction

Looking back on it i would have likely welded a coule of extra timber braces into the gate. Currently the slats are fixed at the top and bottom and have the potential to warp over time. By adding the brace it should stop this happening. Maybe something ill do if i replace all the slatting over time.

Support posts

I would consider going with thicker 100x100 posts. While what is there is fine it would just be a bit more sturdy and support for the various screws and bolts better.

Concrete Footing

I would have spent more time on the form work of the footing to get it level and easier to screed. I know at the time it feels like you just want to get into it and move along but i think i would have spent less time and without a cup grinder if i spent more time on this

Not mix by hand! I know the footing looks relatively small but it does end up being time consuming. I think I spent the whole day on mixing and filling concrete. By the end of the day I was knackered and didnt feel like spending much time on the leveling. Looking back on it the leveling is where you want to spend most of the time to get it right. Look into getting a cement mixer, it makes it much easier. But if you're set on mixing by hand, get a mate around to help.

Electronics

I've considered adding beam sensors and a manual switch at the gate for convinience. Not sure exactly how much power these things would consume so I may look at doing this at a later date. The motor supports these functions