Building Advice

Hawkesbury Sandstone: Geotechnical Building Guide

Building on Hawkesbury Sandstone in Sydney? Learn geotechnical risks, excavation, foundations, drainage and retaining wall considerations.

TL;DR Hawkesbury Sandstone is common across Sydney and the Northern Beaches. It can provide strong founding conditions, but it can also create building risks if the site is not properly investigated. Before building, renovating or excavating, check: rock depth rock strength fractures and joints groundwater slope stability landslip risk excavation access retaining wall loads drainage neighbouring structures vibration and rock breaking impacts foundation design Sandstone is not automatically a problem. The real issue is not knowing what type of sandstone condition exists under your site before design and construction. Introduction Hawkesbury Sandstone is one of the most important geological features in Sydney. It shapes many of the city’s cliffs, ridges, harbour edges, bushland valleys and s…