Questions about building a wooden gate

[cheapdave]

Am wanting to build a double gate made of treated wood - 2x4's and 1x6 x6'. have a 10' opening, so 2 - 5' sections. I think these gates will be a bit heavy, so I am wondering if I should use 4x6 posts to support these things rather than 4x4's? I plan to cement posts in ground about 48" (frost line here is 42") also what size hinges? will 3 - 8" "T" zink plated heavy duty hinges be strong enough? or should I go to 10" and if I use 10" hinges can I go with 2 for each gate? This gate is on a slope - about 6 to 8 inch end to end so I need one gate to open upward about 3" if that is possible. Guess I could offset the hinges a bit, but would I build gate off square on inside to compensate? not really sure how to make that work. I was thinking to pour

10' by 1' wide by 6" deep cement across the whole opening with some 3/8 rebar to reinforce.......would this be strong enough to drive over? Thanks any help appreciated.

[David Nebenzahl]

On 6/29/2009 7:29 PM [e-mail] spake thus:

Phew. Lotta questions there.

I built a gate very similar to this: a set of 2 gates spanning about

10'. 4x4 posts work just fine, so long as they're set deep enough in concrete. (And *don't* just throw the dry bag in the hole and squirt water in; mix the stuff the way you're 'spozed to.) My gates were 2x4 frames and 1x10 or so boards, all reclaimed lumber, so very much like yours (6' tall).

I used some heavy door hinges (removable butt hinges) because I had a shitload of them, 2 per gate. I also mounted casters below each gate to support them. Don't know if you could do this in your situation, but it's a very easy way to help keep the gates from sagging.

[SteveBell]

A five-foot gate isn't unusual. A standard gate is four feet wide.

Consider steel posts.

I'm no engineer, but I would use whichever hinges look the best. I think two of either size would be fine.

You can build an out-of-square gate if you want, and it will work fine, but it's more trouble. Try to make the gate square, but cut off the bottom of the pickets to match the slope. Be sure to use good diagonal braces.

You can buy rectangular steel frames to support gates if you want some extra strength.

That sounds plenty strong to me, but I'm not a concrete guy. In ten feet, I think you want an expansion joint. Don't worry, a concrete guy will be by shortly.

[HeyBub]

In addition to other suggestions, consider bracing the posts by tying them diagonally to the next post.

[Eric in North TX]

That's the ticket, some sort of an H post is needed for a gate post. Any single post will sag some unless it is to the center of the earth. You can be some what sloppy and still have a strong setup if you just H the posts. There are some physics involved, and longer H posts work better. With all wood, you need some way to tension the H, usually wire or cable Xed across rhe corners. Here on the farm, we generally build them from dill casing,15' long with at least 2 cross bars. My neighbor built one from 2 railroad cross ties with a single pipe between & built an X brace out of barbed wire tightened by twisting with a rod, it has supported a 12' gate for over a decade with no sag. It isn't pretty, but it does the job.

[Bill]

If it is on a slope, why not have the gates open out instead of in?

Or make the area level where the gates open.

Other than that, you can be quite creative with this keeping in mind you could go to a welder and have you own hinges made. Hinges which would lift the gate up as it swung open. Or push the bottom out as it swung open.

Also best to have a welder make a metal frame for each gate to support the wood. Use square channel. Then the gates will not sag.

Also don't use wood screws for the hinges. Use stainless steel machine screws with lock nuts.

[Joe]

[DerbyDad03]

re: Or make the area level where the gates open.

[KWP]

Cement around treated lumber is a bad idea, unless you like wobbly posts. Treated lumber shrinks long after the concrete cures.

I second the idea "Joe" has. news: [e-mail]

[HeyBub]

Slight amplification: "Use stainless steel machine BOLTS with lock nuts."

[HeyBub]

Right. When building a fence, I stack the treated pickets in the garage for a month or more (with proper air flow) to let them dry out. If put them up wet, they dry on the vine, so to speak, and you get 3/8" gaps between the pickets.

'Course they swell back up when it rains...

Maybe there's a market for kiln-dried fence pickets?