metal posts for gates - how big?

[CC45]

Hi all,

 

just planning ahead for August / Sept - I'd like to get around to erecting some gates on what hopefully will be our new access.  We are thinking of 6ft wooden gates within a metal frame, sort of like:

 

We would like to use metal posts - with no brick surround.  These black metal posts will match some railings that we will also put down.  The gates will be between 5ft and 6 ft high and 6ft wide each.  How big a post do we need?  Does anyone have experience of this?

 

6" x 6" post?  8" x 8"?  5mm thick metal?  Do we fill the post with something to help strenghten them?  How far in the ground do they need to be? (6'6" out of the ground - 3' in it?) Would it benefit from a square foot welded to the bottom?

 

Any advice gratefully received.

 

CC

 

[Miek]

I would use 100mm square box minimum, 4 or 5 mm wall, galvanised and concreted in at in least 1m. A 6' gate is not that big a load  but you might prefer the aesthetic of 150 or 200 box.

 

A foot on the box is optional , you could plonk it on a pad stone. 

 

[Onoff]

100x100x6 here. Only 'cos it was FREE! 

 

 

[Ferdinand]

One idea: go to your local agricultural merchant and have a look at their metal  gateposts.

 

It may not be an intuitive answer, but they should have posts designed for gates that are up to 12ft wide and up to 7 bar, and so will  be very robust. 

 

When I have these they have usually been approx 8 ft 6 in long, and I have used them around 1/3 in the ground. They seem to come in 3"-5" diameters.

 

You may wish to put some type of cosmetic larger post round it.

 

Ferdinand