Deep pole holes.

[Ooops]

Hi guys

Can anyone suggest how to dig holes approximately 1.5mtrs deep? They are needed to support poles that will in turn hold a sail shade. Does anyone know if there are any hand held augers that might do the job or do I need specialist equipment etc? The poles are 4 meters long and 48mm in diameter.

 

[Deluks]

Do you really need to go that deep? These are metal poles right? (like scaffold?) I don't see how going about 750mm and using a couple bags of postcrete wouldn't hold fast.

If it really needs to be done then dig 1m and hammer in the rest (club hammer needed, and a stepladder!)

 

[Ooops]

Thanks for the reply Deluks

I was going by the 1/3rd in the ground 2/3rds out rule that I read everywhere. We want the poles 2.5mtrs high so therefore I thought we would need to go 1.5mtrs down. (4-2.5=1.5)

Yes they are like scaffold poles. 48mm diameter and 4mm thick galvanised steel.

I have found an auger for hire that will bore a hole about 875mm deep. I promise I won't sue you but do you think that would be deep enough? Obviously I would cut the pole to the desired height.If I may politely ask what would you do?

Thanks again

 

[Deluks]

If I may politely ask what would you do?

I'd ask on here, and sue any bastard who gave me incorrect advice!





2.5 is a fair height though, but the ground should be nice n compact at 875mm Make the hole wider than you would for a fence, moreso at the bottom and use barrowloads of concrete.

The wind on the sail will pull the pole up as well as over, drilling through the bottom of the tube and bolting some threaded bar or angle iron to it will ensure perfect union and alleviate any lateral stress down under.

Disclaimer: I have never done anything like this before.

 

[Ooops]

Thanks for replying, good idea about the threading/angle iron, I hadn't thought of that.

 

[Ooops]

Sorry to throw this one up again but...

Just for information. There is a 2 man earth auger available for hire that will bore a hole 230mm diameter x 2.0m deep. Hard work but it was exactly what we were looking for. I'm not sure if I'm allowed to name the hire company but they are called DD Hire services.

 

[AnerleyBoy]

Yes, I'm a few years late in entering this discussion but we don't fuss about time in DIY . . .

There always seems to be confusion about the two-thirds rule for fence-posts, so here's my understanding of it:
The length of post below the ground should be one third of the length above the ground.

For example -
if the post is to go 6' up, you must go 2' down so get an 8' post;
if the post is to go 7'6" up, you must go 2'6" down so get a 10' post;
if the post is to go 9' up, you must go 3' down so get a 12' post.

To put it another way -
One quarter of the whole post is below the ground and three quarters of the whole post is/are above ground.