AS 2870 Residential Slabs & Footings Inspection
When it comes to residential construction in Australia, what’s under your feet matters just as much as what’s above. The strength and stability of your home depend on a well-designed slab and footing system—and that’s exactly where AS 2870 – Residential Slabs and Footings comes in.
This national standard sets the benchmark for building homes that can handle Australia’s harsh soils, shifting climates, and long-term structural demands. In this guide, we break down AS 2870 in plain English—what it covers, why it matters, and what you need to know as a Perth homeowner, builder, or property buyer.
Table of Content
What Is AS 2870?
AS 2870 is the Australian Standard for the design and construction of residential slabs and footings. It ensures that the structural foundations of homes—such as slabs, beams, and footings—are built to withstand the natural ground conditions and load demands of the structure.
Why Does It Matter?
This standard is especially important in areas with reactive clay soils, like much of Perth. Poorly designed or non-compliant footings can lead to slab heave, wall cracks, structural damage, and costly repairs. AS 2870 sets clear, enforceable rules to minimize these risks and improve long-term durability.
What AS 2870 cover?
The standard outlines:
Site investigation and classification
Structural design of footings and slabs
Performance criteria for various soil types
Requirements for waffle pod slabs, stiffened rafts, and strip footings
Minimum dimensions, reinforcement, and control of movement joints
Site Classifications Explained
AS 2870 categorizes soil sites into classes such as:
Class A: Stable, non-reactive soils
Class S: Slightly reactive clays
Class M: Moderately reactive clays
Class H1/H2: Highly reactive clays (H2 more extreme)
Class E: Extremely reactive clays
Class P: Problematic sites (e.g., filled land, soft soils)
The classification helps engineers choose the correct footing system for stability and safety.
Common Footing Systems in AS 2870
Raft Slabs: Common on reactive soils
Waffle Slabs: Used widely in new builds, especially on flat ground
Strip Footings: For masonry wall supports
Pad Footings: Under isolated load points
Each system must be adapted based on soil conditions and site classification.
What Can Go Wrong Without Compliance?
Cracking or lifting of slabs (slab heave)
Internal/external wall cracks
Doors/windows sticking
Drainage issues and moisture ingress
Structural instability over time
Our inspections ensure compliance with AS 2870, avoiding future legal, structural, and financial headaches.
How We Inspect Using AS 2870?
When we inspect new builds or existing homes:
We assess visible signs of footing failure
Check for conformance to slab thickness, reinforcement, and design layout
Review engineering plans (if available)
Provide a summary report with risk ratings and photographic evidence
We combine industry-standard tools and our knowledge of Perth's soil conditions for accurate inspections.
Book a Slab & Footing Inspection in Perth
Whether you’re building, buying, or dealing with cracks, our team is here to help.
FAQ
Q: Do I need an AS 2870 inspection for a new home?
Yes. If you're building or buying a home, ensure compliance with AS 2870—especially in clay-heavy areas like WA.
Q: What if my builder didn’t follow AS 2870?
Non-compliance could void warranties or lead to major repair bills. We can assess this and provide expert reports.
Q: Is slab heave covered by insurance?
Usually not unless it can be proven that construction was faulty or didn’t comply with AS 2870.
Q: How do I know my slab is cracking due to soil issues?
We can perform a slab movement inspection to determine the root cause and recommend next steps.
Q: How often should slab inspections be carried out?
Slab inspections are typically done at key construction stages—such as pre-pour, post-pour, and practical completion. However, if you notice cracks or movement in an existing home, it's best to book an inspection immediately.
Q: What’s the difference between AS 2870 and AS 4349.1?
AS 2870 focuses on the design and construction of slabs and footings, while AS 4349.1 covers pre-purchase building inspections, including general structural issues, roofing, plumbing, and more. Both are critical, but they serve different purposes.
Q: Can slab issues be repaired if the home wasn’t built to AS 2870?
Yes, but it can be costly. Remedial work might involve underpinning, crack stitching, or even complete slab replacement. That’s why early detection through compliance checks is essential.