Timber Sleeper Retaining Walls in Gosford and across the Central Coast

What timber sleeper retaining wall work in Gosford and across the Central Coast actually involves

Backyard sewer mains can be as shallow as 450 mm, so check the main's depth and location with Council before any post goes in near one. Where a timber wall crosses a sewer main, the posts must be at least 500 mm clear of it. A wall within a sewer main's zone of influence, where a structure could load the ground onto the pipe or excavation near it could damage the pipe, must be certified by a practising engineer as self-supporting. Both lines come from Council's June 2014 guide, written for the former Gosford City Council.

Height and siting still apply

A timber wall built with no council approval is exempt only up to 600 mm, at least 1 m from each boundary and at least 2 m from any other retaining wall on the site. Over that height it needs professional engineering or a development application. The main page sets out the full exempt list, and the drainage page covers the water behind the wall.

Lodge a free Before You Dig Australia enquiry before digging any posthole, whatever the wall's size.

Timber Sleeper Retaining Walls in Gosford and across the Central Coast — common questions

Is there a rule only for timber walls?

Yes, one: where a timber wall crosses a Council sewer main, the support posts must be at least 500 mm clear of the main. The height, boundary and licence lines are the same as for any material.

How high can a timber wall be without approval?

No more than 600 mm, and at least 1 m from each lot boundary. Past 600 mm it needs an engineer or a development application.

Should I check for pipes before the first post?

Yes. A Before You Dig Australia enquiry is free to lodge, and sewer mains in backyards can be as shallow as 450 mm.