// Owners · Buyers · Strata committees
Building condition assessments and reports
A building condition assessment is an engineer's report on the current condition of a building's structure and fabric: the defects, their likely causes and how urgent they are. A dilapidation report records condition as a baseline; a condition assessment tells you what it means and what to do next.
// Overview
What is a building condition assessment?
The short answer
A building condition assessment, also called a building condition report or building condition survey, is a structural engineer's report on a building's current condition. It records significant defects, explains their likely causes and rates how urgent each one is, so you know what matters, what can wait and what to investigate further.
Use one when you need advice for now rather than evidence for later: before buying an older or commercial building, when planning strata capital works, or when new cracks have you worried. If nearby works are about to start, you need a pre-construction dilapidation report instead.
- Who it's for
- Owners, buyers and strata committees
- Main purpose
- Understand defects and decide what to do next
- What you get
- Defects, likely causes, priorities and next steps
- Priorities
- Immediate, short-term or monitor
- Prepared by
- A structural engineer (Engineers Australia · RPEQ)
- Independence
- We don't quote for or carry out repairs
ASSESSMENT · FINDINGSKey takeaways
- It explains what defects mean, not just where they are.
- Each issue gets a likely cause and a priority.
- Cracks are measured and rated against AS 2870 damage categories.
- Engineering only, so the advice isn't shaped by repair work.
// Which report do you need?
Dilapidation report or condition assessment?
They're often confused. The right one depends on whether you need evidence for later or advice for now.
| Dilapidation report | Building condition assessment | |
|---|---|---|
| Main purpose | A dated baseline to prove later change | Understand defects and decide what to do |
| Typical trigger | Works next door, lease start or end | Purchase, capital works planning, visible damage |
| Records existing defects | Yes | Yes |
| Explains likely causes | Not usually | Yes |
| Priorities and recommendations | No | Yes |
| Best paired with | Post-construction report | Crack monitoring where movement is suspected |
Read what a dilapidation report is and how an engineer's report differs from a building inspector's.
// What's included
What does the engineer assess?
A visual inspection of the structure and building fabric we can access, with significant defects photographed, measured and explained.
Cracks in walls and ceilings
Measured, mapped and rated against the AS 2870 damage categories, with the pattern read for likely cause.
Floors and levels
Out-of-level floors, sticking doors and windows, and gaps at skirtings that can point to footing movement.
Footings and ground
Signs of settlement or heave, and the site's soil conditions, such as reactive clay.
Water and drainage
Leaks, ponding, downpipes and drainage near footings, which can drive soil movement.
Visible structure
Framing, beams, columns, slabs and connections we can access, including signs of overloading.
Site elements
Retaining walls, paving, fences and other structures around the building.
Who orders a building condition assessment?
- Buyers of commercial or older residential buildings who want an engineer's view before committing
- Strata committees planning capital works or responding to owners' concerns
- Owners after storms, settlement or new cracking
- Anyone who needs to know what defects mean, not just where they are
// Cracks
How does an engineer rate cracks?
Each significant crack is measured and rated against the damage categories in AS 2870, the Australian Standard for residential slabs and footings. The categories run from 0 (negligible) to 5 (very severe).
- Cat 0Negligible< 0.1 mm
Hairline cracks.
- Cat 1Very slight< 1 mm
Fine cracks which do not need repair.
- Cat 2Slight< 5 mm
Cracks noticeable but easily filled. Doors and windows stick slightly.
- Cat 3Moderate5–15 mm
Cracks can be repaired; some wall may need replacing. Doors and windows stick, service pipes can fracture, weathertightness often impaired.
- Cat 4Severe15–25 mm
Extensive repair: sections of wall broken out and replaced. Frames distort, walls lean or bulge, some loss of bearing in beams.
- Cat 5Very severe> 25 mm
Major repair, partial or complete rebuilding. Beams lose bearing, walls lean badly and need shoring. Danger of instability.
Why do houses crack? Reactive clay and site classes
Reactive clay swells when it gets wet and shrinks as it dries. Houses on reactive clay often show cracks that open and close with seasonal moisture changes. AS 2870 classifies sites by how much the ground surface is expected to move, from Class A (little or no movement) to Class E (extremely reactive).
Knowing the likely site class helps the engineer decide whether a crack fits seasonal movement, a leak or drainage problem, or something else, such as nearby excavation.
Width isn't everything
The standard treats crack width as a guide only. Ten fine cracks in one wall can matter more than one wider crack, and a crack that is still growing matters more than an old, stable one.
AS 2870 site classes: expected surface movement (mm)
- Class A · little or noneLittle or none
- Class S · slightly reactive0–20 mm
- Class M · moderately reactive20–40 mm
- Class H1 · highly reactive40–60 mm
- Class H2 · highly reactive60–75 mm
- Class E · extremely reactive> 75 mm
// What to fix first
How are defects prioritised?
Each issue in the report gets one of three priorities, with the type of remedial work or further investigation it needs.
Immediate
Issues that need attention now, such as signs of instability or a defect that's getting worse quickly.
Short-term
Issues to plan and budget for soon, before they lead to further damage.
Monitor
Defects to watch over time, sometimes with crack monitoring, before deciding on repairs.
How the assessment works
- When you request a quote
Tell us why you need it
A purchase, capital works planning, visible damage or a storm. The reason shapes the scope.
- Within 1–2 business hours
Get a fixed quote
A fixed price for the assessment, with the inspection date confirmed.
- On site
Inspect and measure
The structure and fabric we can access, with significant defects photographed and measured.
- After the inspection
Assess causes and priorities
A likely cause and an urgency rating for each issue.
- Delivery date in your quote
Receive the signed report
Findings, priorities and the type of remedial work or further investigation needed.
Don't repair what's still moving
Where cracking suggests active movement, we may recommend crack monitoring before deciding on repairs. Repeat readings show whether a crack is stable, seasonal or progressive.
Because we're engineering only, we set out the engineering issues and the type of work needed, but we never quote for or carry out repairs. That keeps our advice independent of who does the work.
Want a sense of what's in an engineer's report? See our sample report, or check pricing for our dilapidation reports.
// Related services
Other reports we prepare
Post-construction reports
Re-inspect after works, compare against the original record and assess likely cause.
Learn more Commercial · Strata · LeasesCommercial and strata reports
Offices, shops, warehouses and strata buildings: adjoining works, lease start and make-good.
Learn more During works · MovementCrack monitoring
Track whether existing cracks are moving while nearby works are under way.
Learn more// Questions
Building condition assessment FAQs
Still unsure? Call 07 2150 0579 and an engineer will talk it through.