Changing cracks
Look for cracks that are new, widening, stepped through masonry, recurring after repair or accompanied by separation at corners, openings, skirtings or ceilings.
Artarmon Subsidence: Signs, Causes and a Safe Response
Cracks, uneven floors or sticking doors can have several causes. This guide helps Artarmon property owners document possible ground movement, identify urgent warning signs and organise the right investigation before choosing a repair.
What is subsidence?
Subsidence is downward movement of the ground that can reduce support beneath a building, pavement, retaining structure or service. Settlement is a related term often used for movement as soil or fill compresses under load. In practice, visible cracking or distortion does not identify the cause by itself; movement can also arise from shrinkage, thermal effects, material deterioration, structural behaviour or workmanship.
A safe response separates observation from diagnosis. Record what has changed, control immediate hazards and engage appropriately qualified professionals to investigate the structure, ground, drainage and nearby works before a repair method is selected.
Safety first: if movement appears rapid, a wall or ceiling is unstable, a retaining structure is leaning, a service has ruptured or doors cannot provide safe egress, keep people away and contact the appropriate emergency service, utility, council or competent professional.
This article supports rather than owns the broader service query. For building symptoms, start with SCE's remedial building services; for groundworks and civil interfaces, visit civil services.
Possible warning signs to document
Doors and floors
Sticking doors or windows, sloping or bouncy floors, gaps below skirtings and changes in alignment can be useful observations when their location and timing are recorded.
External movement
Watch for paving that has dropped, voids near footings, leaning fences or retaining walls, separated service entries, displaced drains or recurring ponding close to the building.
One isolated hairline crack may be non-structural, while a pattern of linked symptoms may justify prompt investigation. Crack width alone is not a complete diagnosis; location, direction, change over time and the behaviour of the surrounding building matter.
What can contribute to ground or footing movement?
Water and drainage
Leaking water or sewer lines, failed stormwater, concentrated roof discharge, poor surface falls or long-term moisture changes can soften, erode or change the behaviour of supporting material.
Fill and soil conditions
Uncontrolled fill, variable founding levels, compressible material, reactive soils or poorly compacted service trenches can create differential movement. Site records and investigation are needed to understand what is present.
Nearby excavation or loading
Basements, trenches, utility work, retaining-wall changes, vibration or new loads can alter ground support. The timing, distance, temporary works and monitoring records should be reviewed rather than assumed.
Vegetation and climate
Trees, roots and changing moisture can influence some soils and drains. Seasonal movement may also occur. Arboricultural, geotechnical, drainage and structural input may be needed to separate correlation from cause.
Do not jump to underpinning: underpinning, resin injection, drainage repair, ground improvement or structural repair address different mechanisms. A repair selected before the cause and movement status are understood can conceal symptoms without resolving the problem.
Create a useful movement record
- Date-stamped overview and close photographs
- Crack locations marked on a simple floor plan
- Measurements using the same reference points
- Dates when doors, windows or floors changed
- Rainfall, leaks, drainage failures or plumbing work
- Nearby excavation, demolition, piling or service work
- Available surveys, structural drawings and approvals
- Previous repairs, reports and insurance records
- Changes to trees, landscaping or surface levels
- Any immediate safety or service concern
Keep the record factual. Avoid painting over or filling a changing crack before it is documented and assessed. Monitoring methods and duration should be set by the appropriate professional where movement is material or uncertain.
A staged investigation reduces guesswork
- Desktop and visual review: assemble site history, drawings and approvals; map symptoms; inspect drainage, services, external levels and nearby works.
- Targeted testing: the appointed professionals may recommend level survey, crack monitoring, service testing, CCTV drainage inspection, trial pits or geotechnical investigation.
- Repair and verification: define the cause, stabilisation status, design responsibilities, approvals, construction sequence, monitoring and evidence required to close the work.
The investigation team can include a structural engineer, geotechnical engineer, surveyor, hydraulic or drainage specialist, arborist, builder and relevant authority. Each should work within a clear appointment; a contractor should not be presented as the designer, certifier or cause-determination authority unless that role is separately supported.
Artarmon project interfaces to consider
Artarmon includes residential, commercial and infrastructure activity, often with constrained access and close neighbours. A property assessment may need to consider boundary structures, shared drainage, road reserve or utility assets, strata or common property, traffic and access constraints, nearby construction and the documentation available for earlier alterations.
Local context does not establish causation. The project team should verify the exact property history and coordinate notifications, access, monitoring and authority requirements before intrusive investigation or repair.
For an organised delivery framework, review the SCE System, published examples in the SCE project hub, and SCE's planning tools.
Frequently asked questions
What is subsidence in a building context?
Subsidence is downward movement of ground that can reduce support beneath a building or asset. Settlement and other forms of movement may produce similar symptoms, so cracks or distortion require investigation rather than diagnosis from appearance alone.
Which cracks may justify prompt professional review?
Seek review where cracks are new or changing, stepped through masonry, associated with distortion, repeated after repair or part of a wider pattern involving doors, floors, retaining walls, services or external ground. Rapid movement or instability needs urgent safety action.
Can leaking drains cause ground movement?
Leaks and concentrated water can contribute by softening, eroding or changing supporting material, but they are not the only possible cause. Service testing, drainage inspection and ground or structural assessment may be required.
Should cracks be repaired before monitoring?
Not where movement is unexplained or changing. First document the symptoms and obtain advice on the appropriate monitoring and investigation. Cosmetic repair can remove useful evidence and may fail again if the cause remains active.
Does possible subsidence always require underpinning?
No. The response depends on the cause, extent and whether movement is active. Drainage repair, service repair, ground treatment, structural repair, monitoring or underpinning address different conditions and should follow competent diagnosis and design.
Who should investigate possible subsidence?
The appropriate team depends on the symptoms and site. It may include structural and geotechnical engineers, a surveyor, drainage or utility specialists, an arborist and a suitably qualified contractor. Roles and deliverables should be documented before intrusive work begins.
Move from symptoms to a documented next step
SCE can discuss construction and civil-delivery interfaces for a suitably investigated property concern and help coordinate an appropriate, documented scope.