Advice from James at the Front Counter
Here at CFC Fences and Decks I am in charge of materials sales and I sell materials to Contractors and homeowners. Customers often come to our showroom asking advice on how to build large gates bigger than normal walk gates. Something to keep in mind is with a wider gate the heavier the panel is going to be which will cause more stress on the post that is supporting it. If the post is not sturdy enough to support the gate panel; over time it will pull the post out of plumb (not vertical), causing the gate to not work properly.
Standard Privacy style fences use a 4×4 post which is about 3-7/8”x3-7/8”. This size post is great for walk gates which are between 3’-4’ Wide. Gate panels 5’ or wider I suggest using a 6×6 post which is 5-3/4” x5-3/4”. If your gate panel is going to be 6’ or wider I suggest using 2-6×6’s bolted together. Then using a Strap Hinge rather than a T hinge you can attach it to both posts giving the gate more support. Let’s say your post is sturdy enough you still might have problems with the gate panel sagging and dragging across the ground. Sometimes just the diagonal 2×4 is not enough the keep the gate square. In those cases you could use an Anti-Sag Cable. It attaches at the bottom of the gate on the latch side and stretches up and attaches again at the top of the hinge side of the gate. This cable has a feature that makes it adjustable so as your gate sags over time you can tighten the cable to fix it.
Another solution for wide wood gates 8’ or wider is to use a chain Link gate frame to attach the slats to then using a large 3 or 4” in diameter round metal post with the hardware to match. Gate wheels are great but they work on a case by case basis. They only really work if the ground under and around the gate is the same elevation. The gate wheels we carry do have a spring in them that logically would be able to allow the wheel to follow a sloped ground however it can be tricky to get them to work properly. Wheels work the best on a solid surface like concrete or asphalt.