Large Gate!

[jaz]

how large a gate can you hang on a single leaf wall? It's for a small drive about 2 metres.

[sm_jamieson]

It depends on various factors including how much weight is pressing down on the wall. Thats why gable walls often blow out in gales. Can you describe the wall in more detail. Simon.

[jaz]

The wall is a garden wall of a terraced house. There isn't much room to put a post. Is there a way to strengthen it with a post or something? Thanks in advance. Jaz

[The Natural Philosopher]

If there isn't much room how can it be a large gate?

[sm_jamieson]

A gate into the tardis ? He needs to build it from the inside instead of the outside. Simon.

[jaz]

I think its gonna be to heavy for the wall as it is. i will measure it tonight and post it tomorrow.

[The Natural Philosopher]

What's it made of? Depleted Uranium?

If its tall and narrow, it will be fine. If its a car wide or so, you may need to fabricate a steel U or L section to go underneathe it, and simply lightly tie that to the house.

[jaz]

what d'ya mean?

[The Natural Philosopher]

OK, the best way to hang a heavy gate, is to make a steel U frame, so that you hang the gate on one side, and the other side is the latch side.

The bottom of the U is supported on(or just under) the ground itself, to take the weight.

The steel takes all the bending forces from the gate, all the wall does is to keep it more or less in place - the wall will take no weight at all.

Its not cheap, but a steel fabricator will make a seriously good job of it, and you can then bury it in a trench full of concrete or summat. If steel looks ugly, cover it with wood afterwards :-)

[Jules Richardson]

If you can't strengthen the wall or put a post in, maybe you can add a small wheel on the bottom of the unhinged edge to take the weight (assuming the driveway's flat enough and you can arrange enough play in the hinges to account for any slight variation in surface).

[Man at B&Q]

It can be as large as you want but, if the size of the opening is critical, there may well be not much room for the post.

MBQ

[Andy Dingley]

Bollocks. Any reasonable gate load on a steel post is capable of being coupled into a reasonable ground foundation within a couple of feet, rather than the width of the gate. There's no need at all to support the latch side to this degree, because latches don't have that much force on them. A latch that did put that much force on the upright would have so much friction you wouldn't be able to open it.

You're also assuming that you're building a steel cantilever stiff enough to support this enormous force across the width of the gate. As the force is presumably enormous (else why not just support it from something narrower?), what depth of steelwork are you planning here?

This _might_ be useful if you're building a portable bullock crush for the Royal Show and can't fasten it into the ground, but otherwise you just need a decent hole under the hinge post and a bag or two of post mix. I didn't have this much trouble with my water-powered gate, and that really was big and heavy.

[The Natural Philosopher]

Agreed, but this is the 'uber nice' solution :-)

There's no need at all to

Yu can go deeper and add diagonal braces.

This is just a suggestion of ways to relive cantilever stresses on te wall, how much you use, is of course down to how heavy the gate is and what the soil is like etc etce.

Again, its all down to soil quality, and how the post lies against the house footings.

If you cant sink the post deep because structure is in the way, going steel and making at least an L, if not a U, is good.

I.e. as you realise, what counts is length of material below ground, and coupling that stress into the soil optimally. If you cant go deep, you have to go sideways. AND I am no great fan of ANY cantilever stress in any sort of concreted in structure, I remember the washing line post my parents had, which was sunny into a foot cube of cement about 1953..by

1963 it had a permanent 15 degree tilt, the cement simply gradually putting pressure on the soil and resulting in it slowly shifting.

My farm hgate here puts the total widthh of the gate on the latch too. The poists in the ground simply cant stand the cantilever stresses (bending moment) , and when wet, move, when when dry, come loose. Now that's OK here, but I wouldn't call it a decent solution for a suburban house.

Hence recommending a full 'U'

I take uyout points, but my own experience suiggests that if the job is to be dome properly, nothing sirt of a fuell U ort a pretrty big L will stop teh gate slowly shifting.

IF you can concrete the base not just as a glob round the post but as a complete rebarred slab across the entrance and the post is fairly deep, that probably does as well.

[Peter Parry]

If it is a single brick stretcher bond laid garden wall (each brick laid short end to short end) - almost none. Such walls are often very weak, have minimal foundations and will take very little sideways force. Even a pedestrian gate would require its own gatepost.

[Weatherlawyer]

What sort of houses do they build in your neck of the woods?

I've never seen a gable blown out. And all the weight of a roof is on the adjacent walls to the gables. (Held to the centre by ties used as ceilings/floors)

If the gate is to stop casual traffic would a pole or some-such do? Or an {hinged) bollard of some sort?

[dennis]

Probably stuff that predates the requirement to tie gable ends into the roof structure.. probably 10 years or more old.

I have seen pictures but not an actual event.

[sm_jamieson]

Yep. Before the requirement to tie in the gable, it was definitely a weak point. I think it was in the Birmingham hurricane, you saw several end-of-terraces with the gables blown out. "often blow out in gales" is perhaps overstating the case though ;-) Simon.

[chunkyoldcortina]

When did Birmingham have a hurricane? And how come no-one else saw it on its route from the tropics to Birmingham?

[Bob Minchin]

Pedant! ok so it was a tornado.

Bob