Soil Site Classification Report - (SR)
What is a soil site classification report?
A soil site classification report is a document prepared in accordance with the Australian Standard AS 2870:2011 – Residential Slabs and Footings. This Australian Standard provides requirements and information for the design and construction of residential slabs and footings to the Victorian Building Regulations (VBR) and National Construction Code (NCC).
The soil site classification report provides a site classification to AS2870:2011. It also contains information for planning, designing, costing, constructing and maintaining footings. Soil site classification reports are sometimes referred to as a site classification report or simply a soil report. They are however not a footing design.
When is a soil site classification report required?
A soil site classification report is typically required on all new residential builds, extensions or small sheds, pools and the like.
Why is it important?
A soil site classification report is required for proposed building works to ensure compliance with current building regulations. It enables provision of footings that are structurally sound and appropriate for the soil conditions and ensures the long-term performance of the proposed building. It provides information to engineers, architects, building designers and owners for planning, designing, costing, constructing and maintaining footings.
What are the normal site classifications?
Class A: Most sand and rock sites with little or no ground movement from moisture changes
Class S: Slightly reactive clay sites, which may experience only slight ground movement from moisture changes.
Class M (Moderately reactive soil): Moderately reactive clay or silt sites, which may experience moderate ground movement from moisture changes
Class H1: Highly reactive clay sites, which may experience high ground movement from moisture changes.
Class H2: Highly reactive clay sites, which may experience very high ground movement from moisture changes
Class E (Extremely reactive soil): Extremely reactive sites, which may experience extreme ground movement from moisture changes.
Why is my soil test class P and should I be concerned?
A Class P classification does not mean the site is a literal problem without solutions. The terminology is a requirement of AS 2870 and signifies that the site cannot be classified to one of the normal site classifications. The P class terminology ensures that all applicable constraints of the proposed building site are considered and acts as a prompt to ensure footings for the project are designed by a suitably qualified engineer. There are various reasons for Class P classifications which include fill (foreign placed soil which can be controlled or uncontrolled), possible abnormal soil moisture conditions (eg: vegetation, services, former buildings, drainage problems, excess moisture etc.), slope instability, soft soils and/or collapsing soils (eg: from mining activity or adjacent excavations etc.).
What factors are considered when preparing a soil site classification report
The primary factors considered when preparing a soil site classification report are the soil geological origin, type, composition, depth, strength ,moisture content, plasticity, and its ability to shrink and swell (it's inherent reactivity). Site conditions are also considered and assessed including history, drainage, slopes, vegetation and existing/pre-existing infrastructure.
What information does your soil report include?
Our soil reports provide a concise and clear executive summary that outlines the classification of the site and briefly explains the site constraints. We also include our historical aerial imagery assessment to highlight any key historical features on the subject site and identify the site location and geology with a geological map of Victoria excerpt. Recommended founding conditions for various footing types are included in a founding conditions table. This specifies founding parameters for the proposed footings, including the recommended foundation soil, the bearing capacity of the soil, minimum founding depths and typical founding depths. We also include information about site constraints and recommend design responses for the Engineer who will be designing the footings. Such recommendations include recommending a H1 equivalent reactivy slab on a natural M classifiable site to account for abnormal moisture conditions created by trees, or recommending that the slab is fully suspended on bored piers to account for fill or mining activity.
How does a soil classification report affect construction projects?
A soil site classification report plays a crucial role in construction projects as it provides vital information about the behaviour of the soil beneath the proposed building site and site constraints. It helps Engineers, Builders, Estimators and the Owner anticipate any potential issues with soil movement, construction costs and maintenance requirements.
Are soil site classification reports required for all construction projects?
Generally speaking, in most cases in Victoria, a soil site classification report is required for all residential construction projects that involve new low rise buildings or loadbearing footings. Larger buildings, structures and roads require specific geotechnical reports which are more detailed than a soil site classification report.
Who prepares a soil site classification report?
A soil site classification report must be prepared by a suitably qualified engineer or geologist who is familiar with AS 2870 and the specific conditions in the local area. When the preparer has a good understanding of both soils and building practices, efficient and practical building outcomes are achieved. Civil Engineers are trained in both soil and structural disciplines and our Engineers are experienced in both soils and building areas.
How long does it take to get a soil site classification report?
For most soil site classification reports we generally aim to have the site work and soil report ready for issuing within 8 to 10 business days of acceptance. Priority and shorter turnaround reports can generally be accommodated. We also have an express 2 day turnaround serivce (subject to availability). Please get in touch with us to discuss options as required.
Does it help when the same organisation prepares both the soil site classification report and the footing design?
Yes. When we prepare both the soil site classification report and the footing design, in most instances, the person who attends the site also designs or provides direct input into the footing design. This ensure the intimate site knowledge is fully transferred to the design resulting in an economic and robust footing system.