Advice on Drive way gates

[Yaka]

My 17yr old is planing on making driveway manual swing gates one will be 4m long and one will be 3.7m long and be around 2m in height.

The 4m gate will be using a 100mmx100mm post that is already bolted on to a wall from the previous gate

The 3.7m gate will need a post most likely a 100x100 box section holding it up.

He wants to use 3mm mild steel box sections for the gates and I am concerned about sag/drop over time specifically the 3.7m gate due to the weight

Would we be better off using 1.5mm box sections for the gates? As this would reduce the weight ?

 

[indykid]

If it has diagonals, the gate itself won't sag, but the post might. Are they security gates or just cosmetic?

I'd go with the heavier wall thickness for better durability (you don't mention what tube size he's planning on using) and stick a wheel on the end of each leaf of the gate to support the weight.

The 100mm freestanding post would concern me more than the gates. What's going in/on the frame and what's the post anchored in?

 

[Pigeon_Droppings2]

Very difficult to say without knowing the design of the gates.

Mine was a security gate (very heavy)...100x100x5mm post was insufficient...and it was filled with cement!

With the benefit of hindsight if I did it again I would choose an eye beam post.

 

[Nomad]

I used a 100x100x5 post to hold a 2m wide ornamental gate ( fairly light, not a solid gate) on a driveway.
The post was fine but had a lot of spring, digging the post hole 3ft deep (then concrete filled) felt like a lot of work but anything less would have sagged over time.

 

[8ob]

That's two big gates, definitely join/bridge the two posts together underground. Anything that big could pull a post over in time. I would suggest building an H frame.

Bob

 

[wyn]

These were around 4m each.
The posts were 120x120x5 with a diagonal from the top back to another steel post.
I think they are still working ok.

 

[Onthespotwelding]

I would go bigger on the posts 200x200x30 with a huge base plate fitted to the bottom. Set in at least a meter deep of concrete.

3mm box section will sag under its own weight over 4meters. It will need to be thicker with diagonal bracing to keep the gate square.

 

[DAPPH]

My 17yr old is planing on making driveway manual swing gates one will be 4m long and one will be 3.7m long and be around 2m in height.

The 4m gate will be using a 100mmx100mm post that is already bolted on to a wall from the previous gate

The 3.7m gate will need a post most likely a 100x100 box section holding it up.

He wants to use 3mm mild steel box sections for the gates and I am concerned about sag/drop over time specifically the 3.7m gate due to the weight

Would we be better off using 1.5mm box sections for the gates? As this would reduce the weight ?

I used hot galv'd 100x100 mm box with a 10 mm wall and three thick greased brass washer on each hinge , top two hinges had mills pins in them to stop them being stolen

Will continue later ...

 

[Tigman]

You can get a jockey wheel attach to the gate if the drive is smooth , they are spring loaded F H Brundle !

 

[Yaka]

If it has diagonals, the gate itself won't sag, but the post might. Are they security gates or just cosmetic?

I'd go with the heavier wall thickness for better durability (you don't mention what tube size he's planning on using) and stick a wheel on the end of each leaf of the gate to support the weight.

The 100mm freestanding post would concern me more than the gates. What's going in/on the frame and what's the post anchored in?

the frame of each swing gate is 50x50mm with the internal ones 25x25mm , i have attached a picture of what is planned

Very difficult to say without knowing the design of the gates.

Mine was a security gate (very heavy)...100x100x5mm post was insufficient...and it was filled with cement!

With the benefit of hindsight if I did it again I would choose an eye beam post.

yes the freestanding post is the one i am worried about.

I used a 100x100x5 post to hold a 2m wide ornamental gate ( fairly light, not a solid gate) on a driveway.
The post was fine but had a lot of spring, digging the post hole 3ft deep (then concrete filled) felt like a lot of work but anything less would have sagged over time.

the plan was to dig a 3ft hole but would digging a deeper hole help?

That's two big gates, definitely join/bridge the two posts together underground. Anything that big could pull a post over in time. I would suggest building an H frame.

Bob

I would go bigger on the posts 200x200x30 with a huge base plate fitted to the bottom. Set in at least a meter deep of concrete.

3mm box section will sag under its own weight over 4meters. It will need to be thicker with diagonal bracing to keep the gate square.

this is my worry and something i wish to avoid

I used hot galv'd 100x100 mm box with a 10 mm wall and three thick greased brass washer on each hinge , top two hinges had mills pins in them to stop them being stolen

Will continue later ...

this roughly what is planned, the left post is bolted to a wall and from memory is 3ft into the ground so was thinking the same for the post on the left but will have to be freestanding

 

[frank horton]

there gonna be heavy....better if the could roll on a track....even Bi-Fold....the sort that will go around corners...
this gate is 9m long and in 2 pieces....a 5 year old can push it along...

 

[Bravheart]

For a quick job ive just hung some 12' field gates, ok a bit lighter than yours but on 7'6" posts 7" wide punched in with a knocker too 4'. Solid as a rock will last a while.

 

[ahebron]

These were around 4m each.
The posts were 120x120x5 with a diagonal from the top back to another steel post.
I think they are still working ok.

View attachment 488997

I alwys thought gate diagonals went the other way. From bottom corner at post side up to top corner jam side.

 

[sako243]

the plan was to dig a 3ft hole but would digging a deeper hole help?

We've got a pair of similar sized gates, they only have 50x50x3 box around the frame and a 50x25x2 RHS across the middle. They're not sagging but an H frame as @8ob suggests was buried underground and concreted in. This was welded fully out of 100x100x5 box and the corner posts sunk 4ft underground. There's about a cube of concrete in each corner let alone.

The issue is actually the post with the postbox on is actually flexing the steel post and bending it. Ideally it needs the horizontal post lengthening and a brace to pull it back.

Our post box has been changed since this photo but the left hand upright is twisting over above ground.

 

[arther dailey]

gates like these always put a smile on my face as 99% of the time surrounding walls or hedge can be hopped over easily , there is one localy , massive property , huge ornamental gates yet within a couple yards either side nothing !

 

[sako243]

@arther dailey these weren't so much security (nothing will deter those) but privacy. Once I had some time the tops were going to be "rolled" to have a curved top but that's a nice to have project.

 

[indykid]

I alwys thought gate diagonals went the other way. From bottom corner at post side up to top corner jam side.

They do with wooden gates because wood joinery is poor in tension, but welded steel is fine in tension. It's arguably better run in tension because if run in compression, such long spans will tend to let the tube sag where it's then prone to buckling, especially if smaller tube is used for the diagonal.

 

[KimB]

I build a single bi fold gate about 3.3 wide and used a 100 x100 x 10mm post that I buried a meter in the ground and I also had bracing underground that spans around 1-1.5m in both directions the gate moves in.
I made mine out of 2.5mm box section. And clad it with resin board I think it’s called.

Those sizes you’re talking about are seriously heavy. I weight tested mine and I can stand on the end of it and it only moves a tiny amount but I’d be cautious about not only the size of material you want to use and also if the posts are properly fixed.

Also before anyone says. The diagonal supports are the correct way for their use.

 

[indykid]

I build a single bi fold gate about 3.3 wide and used a 100 x100 x 10mm post that I buried a meter in the ground and I also had bracing underground that spans around 1-1.5m in both directions the gate moves in.
I made mine out of 2.5mm box section. And clad it with resin board I think it’s called.

Those sizes you’re talking about are seriously heavy. I weight tested mine and I can stand on the end of it and it only moves a tiny amount but I’d be cautious about not only the size of material you want to use and also if the posts are properly fixed.

Also before anyone says. The diagonal supports are the correct way for their use.

I like the bell crank for the bifold leaf. I wondered how you were getting away with the electric opener til I spotted it.

 

[arther dailey]

@arther dailey these weren't so much security (nothing will deter those) but privacy. Once I had some time the tops were going to be "rolled" to have a curved top but that's a nice to have project.

was nt a critisism , have you seen the old westens , huge ranch , great big entrance posts and...nothing either side , I just think its funny , in you case will be easy enough to put up some railings either side , time is the thing though , always other things to do . re privacy , we have iron gates which we put a lock through at night , tother morning they had been pulled hard and dug up with the rods quite a bit , so some one thought they were going to get in...no matter what you do though ...they cut through the sheep wire behind the privit a while back to enable breaking into one shed. they are about constantly , last year alarm went I walked out to see my tig being carried out by a person of travelling decent (desent) , shouted out , and got the reply ok have it back then , he dropped it on the floor and got in his van and off he went.. he had taken it from the back of my truck in the driveway.