lazzah

Hi all, I want to try my hand at building a side gateway which will join up with the one at the side of my next-door neighbour's house. The main column will be 680mm (3 bricks) long, one brick wide and will be about 2440mm high. Could I get away with laying the bricks directly onto the side path (it's fairly level) or is it essential to have a concrete foundation? If the latter, how deep do I need to go? Any advice gratefully received. Many thanks, Larry.