1st March

Retaining walls

In the beautiful suburbs of Auckland and with the views they provide, it is inevitable that several homes will have retaining walls. With retaining walls, the frequently asked question is what consents are required for the construction or alteration of a retaining wall.

The simple answer is that it is based on the amount of ground that the retaining wall supports...A building consent is not required for the construction or alteration of a retaining wall that retains not more than 1.5 metres depth of ground. The retaining wall must also not support any surcharge. A surcharge is any vertical pressure applied to the ground surface close to a retaining wall.

In summary for an urban retaining wall:
Retaining wall = or < 1.5 m / no surcharge: Building Consent NOT required
Retaining wall = or < 1.5 m / with surcharge: : Building Consent required
Retaining wall > 1.5 m / with or without surcharge: : Building Consent required

For rural zones there are further considerations that apply and the requirement for depth of ground to be retained is double that of urban zoned areas.

There are also other considerations, such as whether the building work does not breach any other enactment.

A retaining wall may require a barrier to protect people from falling. If the retaining wall is more than 1 meter and the area is associated with the use of a building then a barrier is required.