Timber in Contact with Ground
Timber structural elements - deck posts, pergola framing, sleeper retaining walls, or firewood stacks - sitting directly in or against soil create an unobstructed termite pathway into the building and accelerate fungal decay. AS 3660.1 requires all structural timber to be isolated from soil to maintain a visible inspection zone; ground contact eliminates this requirement entirely and removes any chance of early detection.
Severity rationale
Across 1,704 observations the modal score is 3, concentrated heavily at that level (911 observations, 53%). Severity 4 accounts for 35% of findings - a notably high proportion reflecting how often inspectors find active conducive conditions rather than just a marginal clearance failure. Scores of 1 and 5 are rare (2 and 1 observation respectively). The average of 3.23 sits at the upper moderate range, pushed up by the large 4-cluster; the defect is elevated where timber is framing-proximate rather than an isolated garden structure.
Causes
- Deck or pergola posts set directly in soil or in concrete footings without post stirrups
- Timber sleepers used as garden edging or low retaining walls within the termite exclusion zone
- Landscaping changes since construction raising soil level against existing timber elements
- Firewood, offcuts, or timber debris stored on the ground against or near the dwelling
- Improper installation of decking where bearer ends contact grade
Symptoms to look for
- Deck or pergola post bases embedded in or flush with soil surface
- Sleeper retaining walls in contact with building framing or within the subfloor zone
- Timber members with visible darkening, softening, or staining at ground level
- Termite mud leads or frass trails visible at or near ground-contact points
- No clearance gap between timber elements and grade
Remedies
- Lift deck or pergola posts off grade using galvanised stirrup anchors cast into concrete pads
- Replace in-ground timber sleepers with masonry, steel, or concrete retaining options where adjacent to the dwelling
- Remove and relocate firewood and timber offcuts well clear of the building perimeter
- Engage a licensed pest inspector to assess whether concealed termite activity has already commenced (AS 4349.3)
- Restore a minimum 75mm soil-to-timber clearance and re-establish a visible termite inspection zone around the perimeter
Where we see this most
These suburbs show the highest concentration of timber in contact with ground in our inspection data (minimum five observations). Click a suburb to see its full defect profile.
Worth asking our inspector about this specifically.
Ground-contact timber is a conducive condition, not necessarily active infestation, but it warrants a licensed pest inspection and remediation of the contact points. Prioritise where the timber is attached to or adjacent to main-structure framing.