how deep do I need to plant a 4m high pole?

[Gareth]

SWMBO has said she wants a washing line like our neighbours.

This appears to be supported by a ~4m high scaffold pole at each end and a pulley to raise and lower the line. How can I work out how deep I need to bury the pole to support 4m of pole above ground?

Thanks for any help.

Gareth

[The Medway Handyman]

High maintenance woman huh?

Rule of thumb is 20% in the ground I reckon.

[Andrew Gabriel]

I would suggest finding a suitable sleeve to hammer into the ground flush (or concrete in the ground) into which you slot the longer pole. I use the ground socket spikes for clothes airers for 3 metre light weight aluminium poles with no more lateral force than the wind, but you'll want something more substantial for a 4m scaffold pole with a line pulling on it, and I've only seen them for 1.25" and 1.5" poles (IIRC, scaffolding is 2").

[Nightjar]

The neigbours have probably used a standard length of pole, which suggests they have either 1m or 2.4m buried.

Colin Bignell

[The Medway Handyman]

You can get scaffold type tube in 5 sizes from

its in 3.2m ex stock, longer lengths to order.

[Jules Richardson]

I usually do 33% below-ground as a general rule.

If you don't want it to flex, maybe use something stronger than scaffold (our line has telegraph poles at either end, supporting four lines of around 30' in length - it's a bit of a monster ;-)

cheers

Jules

[Gareth]

Thanks for your reply.

Is that 33% of the total length or the above ground length? I.e for 4m above ground do I need 2m or 1.3m below ground?

I don't want it to flex but a telegraph pole seems a bit excessive for a washing line - maybe a tumble dryer would be easier :)

[Gareth]

Thanks. There is a branch not too far from here.

[Gareth]

Thanks for the reply.

[Gareth]

Thanks.

[brass monkey]

We used a scaffold pole about 8' high with about 2' in the ground (10' total) with concreted rubble and bricks. I.e, dig 2' hole, maybe 18" wide, drop in pole and fill with rubble, bricks, cement. My !"£$" son ran at it one day, grabbed it as he passed causing it to bend starting at about 3' up with the top ending up about 12" from where it was. Absolutely zero sign of movement at ground level, still firm as a rock. I still can't believe it.

[Tim Streater]

Dog house for you mate, if the Boss hears that one!

[PeterC]

But a tumble drier on a 4m pole...?

[Gareth]

No that would be stupid. I was thinking of welding the pole to the side of the drier rather than sticking the pole in the ground :)

[Skipweasel]

If you put blades on it, you could make the drier spin in the wind, generate its own power and save the planet.

[SS]

Just stick it 6 inches into the ground and when it falls over tell her she put too much washing on the line. Dont they do proper clothes poles nowadays, they used (years ago) to have them about 2 meters high and sunk in a lump of concrete, i think no more than a couple of feet deep and never seen one topple over yet. Usually done with 3 poles (triangle ) or a square with 4 poles.

[Skipweasel]

Our local timberyard still sells proper galvanised washing poles with the two crossed bars at the top. Ours started as 2.5m but I sank the first foot or so in a large lump of concrete. That was a few years ago and it ain't moved yet.

[Donwill]

Hope you've got a long car :-)

5M :-(

Don

[robgraham]

Yes, it should be in a LARGE lump of concrete as the sideways pull is pretty significant.

Remember the washing goes out semi dry having been spun, but like cricket matches, that's a signal to the rain gods to perform and the washing then gets really heavy - the wind gods then do their thing and low and behold, if you don't put some serious weight at the foot of each pole, everyone's efforts will be in vain and you certainly will be in the doghouse.

I took two poles out and the concrete mass must have been at least 2 ft in diameter. Fortunately I had a mini digger available to lift them and bury them in another hole. Just bear the this in mind as once in they are not easily removable.

Convince SWMBO to stick to a whirligig - can be put anywhere and is a nominally balanced load so none of these problems exist. OK they have a finite lifetime but I suspect that a replacement every 10 years is preferable. Rob

[Jonathan]

My ten foot scaffolding poles are hammered in about two-three feet and have slightly moved inwards towards the centre but not enough to worry about. they have been there five years without any problems and get used a lot.

Jonathan