Retaining Walls

Taranaki is made up of undulating land, valleys with thieving streams and rivers that carve their way to the Tasman sea. As a result, most houses here in new Plymouth are built on the sides of hills.
 

Retaining is so important to a property. It is the backbone of holding steep sections together and protecting them from eroding and slipping away. A new timber retaining wall can add great street appeal to your property.

Retaining Wall After 4

Frequently Asked Questions

How high can I build a retaining wall until I need consent?

1.5m High

What is the minimum size posts I should use?

125mm x 125mm H4 treated posts

 

When is an engineer needed?

Once a retaining wall is over 1.5m it requires an engineer to design plans and consent obtained from the council.

 

Why do most concrete retaining walls get cracks in them?

Most of the time cracks form because of movement. This can be caused by earthquakes or over a long period of time tree roots.

Why does a retaining wall start to lean over?

This can be caused by two things: 1. A lack or no draining system behind the wall, 2.Timber posts have not been dug deep enough. (Rule of thumb with retaining wall posts, the height you go up is the height you dig down).

Andy & Jill's Retaining Wall

Andy and Jill's concrete retaining wall had seen better days.

 

Large cracks had started to form from the root systems of flax bushes growing above the wall which were becoming a concern.

Before any demolition began, a services scan was carried out to locate all gas, water, sewage

and electrical services.

A small digger with a breaker and a bucket was used in conjunction with a small tip truck to break up and remove all of the existing old concrete wall. The digger was also used to dig the post holes.

  • 150mm x 150mm structural tested timber posts were concreted into the holes at a 15-degree angle. 

  • A punched drainage pipe with a filter sock was installed behind the posts to help with water drainage. 

  • 200mm x 50mm tongue and groove H4 boards were installed.

A timber capping was fixed to the top to finish it off.

Retaining Wall After 2
Retaining Wall After
IMG_20210213_121809
Retaining Wall After 3