Most of a tree’s critical structure is hidden below ground. The root system anchors the tree, absorbs water and nutrients, and interacts with surrounding soil, pipes, and foundations. When problems develop underground, a professional root inspection is the only way to accurately assess the situation.
When Do You Need a Root Inspection?
A tree root inspection is recommended in several common scenarios:
- Before construction or renovation – Any excavation, trenching, or building work near a tree’s root zone can damage roots and destabilise the tree. An inspection determines what is underground before work begins.
- Suspected pipe damage – If a plumber has identified root intrusion in your pipes, an arborist inspection can identify which tree is responsible and whether root management or removal is needed.
- Foundation cracking – When building movement is suspected to be caused by tree roots extracting soil moisture, a root inspection helps confirm or rule out this diagnosis.
- Tree stability concerns – If a tree is leaning, has had root zone disturbance, or shows signs of decline, a root inspection assesses the remaining anchorage.
- Council or development requirements – Many councils require an arborist report including root assessment as part of development applications near significant trees.
- Neighbour disputes – When roots from a neighbour’s tree are causing damage, a documented inspection provides evidence for negotiation or legal proceedings.
What a Root Inspection Involves
A thorough root inspection typically includes several components:
Visual Assessment
The arborist examines the base of the tree and surrounding area for visible issues such as surface roots, root plate lifting, soil cracking, fungal growth, and signs of decay at the root flare. The overall health and structure of the tree above ground is also assessed, as canopy condition often reflects root health.
Ground-Penetrating Radar (GPR)
For detailed mapping of root locations without excavation, some arborists use ground-penetrating radar. This non-invasive technology sends radar pulses into the soil, creating a picture of root distribution and identifying major structural roots near infrastructure.
Air Spading or Hydro Excavation
When physical examination is necessary, air spading uses compressed air to blow soil away from roots without cutting them. This exposes the root system for direct inspection of condition, decay, and damage. It is the gold standard for root assessment, commonly used for high-value trees.
Soil Analysis
In cases involving subsidence, the arborist may assess soil type and moisture content. On clay soils, understanding shrink-swell characteristics is crucial for determining the influence of tree water uptake on foundation movement.
Root Inspection Costs
The cost of a root inspection depends on the methods used and the complexity of the site:
- Visual root assessment – $200 to $500, often included in a standard arborist consultation.
- Root mapping with GPR – $500 to $1,500 depending on the area covered.
- Air spade investigation – $400 to $1,200 per tree.
- Comprehensive report with findings – $500 to $2,000+ depending on scope.
For information on report costs specifically, see our tree root damage to foundations guide and the detailed arborist report guide.
What Happens After the Inspection?
Based on the findings, the arborist will recommend a course of action, which might include root pruning, root barriers, ongoing monitoring, or in serious cases, tree root removal or complete tree removal. The inspection report provides the evidence base for making informed decisions and, if needed, supporting council applications or insurance claims.
If you suspect root problems on your property, getting an expert inspection early can save significant expense down the track. Find a qualified arborist in your area and arrange a root inspection to understand exactly what is happening below ground.