Our Services

ARC Retaining and Contracting can help you throughout your entire project by offering solutions for all you retaining wall and excavation requirements.

We work closely with your surveyors, geo-tech and structural engineers so that you get the best advice and plans; when properly constructed, a well-made retaining wall is a long-lasting and aesthetically pleasing addition to many yards and gardens. Whether you’re looking to preserve the integrity of your landscape or simply add a decorative feature, ARC Retaining & Contracting has what you’re searching for.

Under Schedule 1 of the Building Act 2004, the construction of a retaining wall does not require a building consent when it is less than 1.5 m high and ‘does not support any surcharge or any load additional to the load of that ground (for example, the load of the vehicles on a road)’ Retaining walls that are over 1.5 m high and those supporting a surcharge require a building consent.

Timber pole retaining walls and in-ground walls – with the use of round poles being the most common for their structural integrity and cost efficiency, there are also options available for the use of square post.

The integrity of a timber retaining wall relies on strong piles. A retaining wall has to be strong enough to support the load of soil pressing against it. This load determines the size of poles and the thickness of retaining timber to be used so that the poles or timber do not break.

The most important part of the wall is the part below the ground that anchors it. If he footings, foundations or the soil is weak then there is nothing stopping it from falling over. Generally the construction involves drilling to depth, and concreting the timber poles in place, often piles go down as deep as the wall’s height however once over 1.5 metres high, these dimensions’ increase. 

One of the key things is to drain water from the bank behind the wall. If a wall doesn’t drain well then the bank behind and footings can become waterlogged and the wall fall over. Good drainage is critical to the success of a retaining wall.

Prices range widely for timber and the total cost will depend on the size of the boards used and how far the posts are spaced apart.

 Palisade walls also known as in-ground walls, utilise deep piles, generally either encased timber or reinforced concrete piles, closely spaced, embedded into the harder subsoils, thus retaining the more unstable upper layers.

Commonly a reinforced concrete capping beam is installed along the top to link the piles together as a unit.

Palisade walls are are an effective ground retention solution, usually used for heavy duty applications supporting substantial loads.

Steel retaining walls are constructed with either UC or UB columns.

For longevity the steel beams can be painted with epoxy to match and tie in surrounding colours and themes or hot dip galvanised to prevent corrosion. These can be in-filled with round poles as whalers, or timber planks fitted between the steel.

Steel retaining walls can be constructed on boundary lines with minimal intrusion onto the property, and can be constructed from the top down while the site is being excavated, or by battering back.