What is a Site Classification

Site Classification Explained

A site classification is a report that identifies the type of soil on a building site and how it will react to moisture changes. This classification is required before designing footings and foundations for houses and other structures.

The site classification helps engineers determine the correct footing design to prevent movement, cracking, and structural damage.

In Australia, site classifications are determined in accordance with standards published by Standards Australia, specifically AS 2870 for residential slabs and footings.

Why Site Classification is Important

Different soil types expand and shrink depending on moisture levels. This movement can cause serious damage if foundations are not designed correctly.

A site classification ensures:

• Safe foundation design
  
  

• Compliance with Australian building standards
  
  

• Reduced risk of cracking and movement
  
  

• Long-term structural stability
  
  

Most councils and engineers require a site classification before construction begins.

Site Classification Categories

There are six main site classes:

Class A – Non-reactive

Stable soils such as sand or rock with very little movement.

Class S – Slightly Reactive

Slight ground movement possible with moisture changes.

Class M – Moderately Reactive

Moderate movement. Common in many Adelaide areas.

Class H – Highly Reactive

High ground movement. Requires specialised footing design.

Class E – Extremely Reactive

Very high movement. Requires careful engineering.

Class P – Problem Site

Problematic sites such as:

• Fill
  
  

• Soft soils
  
  

• Loose ground
  
  

These require special design and investigation.

Site Classification Adelaide

Site classifications are essential for construction projects across Adelaide and South Australia due to the reactive clay soils common in many areas.

Professional soil testing ensures your foundation is designed correctly and complies with Australian Standards.