Before your builder lays the slab of your new home, the concrete piers have to be put in place. This involves your builder excavating a number of holes throughout the site, which will later be filled with concrete to strengthen the foundation of your new home.
The depth and width of these holes are determined by site engineers, however the depth of each pier on the site can vary depending on the amount of fill on the land. The best way to visualise piers is to think of them like the legs of a table.
Below is a picture of completed concrete piers:
Keep in mind that some builders will only give you an allowance for piering as they may not have done a soil test at the time of signing the building contract. If the allowance is minimal you may be up for extra costs once your builder has gone on site and undertaken the relevant soil tests.
So make sure your builder does a full site inspection and soil test before contracts are signed so that your builder can give you a fixed price for concrete piering with no unexpected surprises afterwards!