A Simplified Explanation Of Site & Earth Works Part 3

Site & Earth works - cut to fill average levels

In this post, the 3rd in the series of, A simplified explanation of site & earth works, we continue with an even more simplified explanation of the process and items that you may encounter when having your home quoted.

It must be noted, that if any of the site & earthworks items are required, then you will need that item, and if a Builder provides you with a quote, and those items don’t form part of your quote, you will need to ask where and when they will add it to our contract.

Service runs

On a rear strata lot, (a house behind a house), all of the services will need to be taken to the rear house from the supply location of the front house to the connection point in the rear home, this includes power, water, sewer, telephone, possibly NBN, (if included) gas and any other item specifically required for your site and will generally be in the same trench.

Organising the service runs requires a great deal of coordination to have all the trades on site within a limited time, and even more co-ordination for a rear strata block.


On smaller and rear strata blocks, piling is becoming more and more common. When a block is subdivided and a new sewer line is created for the new home, or to protect the old sewer line, the Water Corporation may require that an easement (an area that is not allowed to be built on) is included and piles must be installed.

Sometimes piling is used when there is a difference in the levels from one block to another and retaining is not an option. Piles generally steel screw piles, are driven into the ground for support and finish inside the footing that they are to support, and a retaining wall is built on top of the ground.

An engineer will design a piling detail (a report) that is forwarded to the piling contractor to ensure that the piles are the correct size and installed to the correct depth.

Storm water disposal

Almost all shires (local authorities) require suitable storm water disposal systems in place as part of the building permit conditions.

Some shires also require a hydraulic engineers report to detail the exact type, size and amount of stormwater disposal tanks, (soakwells) that will be required for the lot.

Stormwater disposal can be either concrete tanks or the more recent polypropylene modular systems, or in some shires connection to the shire stormwater catchment.

Removal of excess soil

When the footings, drains (sewer) and stormwater systems are dug out, there is a remarkable amount of excess soil created.

On a larger block, the earth worker will create a large hole in a clear space to dump some of the excess soil in, which in turn costs less for the earthworks as the soil doesn’t have to be taken away from site. However, on smaller lots, there is no room to dig large holes and often there can be up to 20 cubic metres of excess soil that needs to be removed, as it can’t stay on the site.

Limestone access track

In a lot of Perth’s suburbs, there are a lot of sandy sites and especially when building at the rear of an existing home (rear strata or battle-axe lot) it’s necessary to place approximately 100mm of limestone down over the access track to allow trades and suppliers to get their vehicles near the building site. The limestone will compact the more it’s driven on giving the trucks and machinery more traction so that they don’t get bogged.

No Surprises or additional unknown costs

With Central Avenue Homes, completing these works, you will be guaranteed:

  • All costs will be provided upfront
  • You’ll have no unexpected or unknown costs.
  • They will be supervised by us as part of the building process.
  • They will be completed to Shire and Engineer requirements.


For a more specific idea of what your blocks Site – earthworks will include contact us at Central Avenue Homes.

Or call and speak to our in house designer 9456 3366