# Gate Design Question



## rocknroll99 (Apr 12, 2010)

Hello all, 
I have a quick question from tNew Zealand. Please bear with me as I am a Chemist not a engineer. 
My Partner and I are building a driveway gate and arguing over details. 
It is a simple picket gate with a brace a bit like this.









Question is the height of the gate (i.e. the distance between the horizontal bracing beams) make a difference to the gate. 

I want to make this distance greater (about 3-4 feet (1.2 m) apart) to give the gate more strength. She wants them smaller about (about 2 feet (about 60 cm) apart) for aesthetic reasons. 

Will this difference between braces affect the strength or usability of the gate? The gate will span a 4 meter gap (not sure what that is in feet say 13 and a bit feet)

Cheers very much for your help here
Regards Rocknroll


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## Just Bill (Dec 21, 2008)

For a gate that spans that far, bracing is essential and needs to be substantial. I would add an 'X' brace, instead on the one you show. As to how it looks, without good bracing, it won't last long enough to look at.

And when doing a gate this size, I glue(waterproof glue) and screw or bolt everything together.


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## vsheetz (Sep 28, 2008)

A wooden gate of that size is going to be hard to brace enough to keep it from sagging. If possible, I would suggest to make it a pair of gates to reduce the size and weight.


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## Yoyizit (Jul 11, 2008)

The brace must make a triangle with the gate outline; it's a figure that cannot change shape without changing the lengths of its sides.

It's 13' long and 3' high? 

How much does the wood weigh? This will give some idea of the fastener shear strength necessary.


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## troubleseeker (Sep 25, 2006)

You are not going to be able to build a 13' by 3 or 4' high wood gate and have it not sag substantially, unless you incorporate some type of metal frame on the backside. On this width, the diagonal brace will be at such a low angle that it will be functionally useless for support. How about a pair of smaller gates?


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## Yoyizit (Jul 11, 2008)

You could do several vertical and diagonal braces, like a truss design. In principle, it would work. 
You may have to use through-bolts rather than wood screws, however. 
For a 300# gate the upper hinge will have 1500# tending to pull the hinge off the post.

Or, you could put a swivel caster on the gate bottom at the end, if the ground surface permits it. Rough surface = bigger wheel.


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