We explain a clear, safe plan so you can monitor a crack in your home with confidence. Our engineering-led team helps you separate cosmetic faults from genuine structural problems in Melbourne houses.

Start with simple observation and careful documentation. Mark endpoints lightly, date them and take square-on photos in good light. Note width, direction, temperature and humidity each time.

Check after heavy weather, daily if active, then monthly or every two months if steady. Widening is more serious than length. Horizontal breaks near door headers, windows and corners need attention.

Safety is our priority. If doors stick, floors slope or new gaps appear, stop DIY and call for an engineer. We are VBA registered, insured and offer free assessments. Call Chris: 1300 970 930 or Email Chris: chris@underpinning-melbourne.com.au.

Key Takeaways

Begin with patient observation: mark, date and photograph each crack.
Track width, direction and environmental notes with every check.
Frequent checks after extreme weather, then space them out if stable.
Horizontal movement and accompanying symptoms suggest structural concern.
Our VBA-registered team offers free assessments and certified solutions.

Why crack movement matters in Melbourne homes

Not all surface faults threaten a building, but movement that widens needs attention. We prioritise homeowner safety and guide when simple checks are appropriate and when expert help is necessary.

Safety first: when simple checks are suitable

DIY checks suit hairline cases with no rapid change and no safety risks. Check more often after heavy rain or heat, then space checks if the situation is steady.

Stop DIY if width increases, doors or windows stick, floors feel uneven, or services are nearby. At that point, call our VBA-registered engineers for a free assessment. Call Chris: 1300 970 930 or Email Chris: chris@underpinning-melbourne.com.au.

Common reasons behind movement

Melbourne soils swell and shrink with wet and dry cycles. Foundation settlement, moisture ingress, natural ageing and temperature shifts are frequent reasons for lines in plaster and concrete.

Watch location and direction. Horizontal lines near door heads, corners and upper storeys raise concern more than length alone.

Tools overview: simple through specialist

Start with pencil marks, tape and square-on photos. Step up to comparator cards, a crack gauge with a grid and crosshair, digital calipers or an optical comparator for precision.

For concrete depth, UPV is a specialist option. Learn more about our diagnostics via the wall crack diagnosis tool.

Tool	Use	When to choose
Pencil/tape & photos	Baseline location, direction and simple width checks	Hairline, stable cases; quick checks over time
Crack gauge (grid & crosshair)	Reads direction and width change across either side	Visible change or unclear movement direction
Digital caliper / microscope	Precise width measurements on small pieces	Slow, minor movement where accuracy matters
UPV	Assess depth in concrete elements	Suspected deep concrete defects; specialist use

How to monitor cracks step-by-step with simple and reliable methods

Make a simple, repeatable record at the outset so every later reading is comparable.

Mark and date endpoints

Mark each endpoint with a pencil and date it. Use clear tape if you prefer not to touch the paint. This gives a stable starting point for measurements.

Take square-on photos and set reminders

Photograph the area straight on in good light. Keep images in a dated folder and set calendar reminders for repeat checks. Consistent photos form reliable data over time.

Baseline width checks

Begin with a comparator card, then use a crack gauge or digital calipers for finer readings. These methods give baseline width and distance values for later comparison.

Tell‑tale gauges and demec studs

Fit a tell‑tale gauge with two plates fixed either side of the line. Read the grid and crosshair for X and Y movement. For precise one‑direction work, place adhesive demec studs and measure the distance between dimples with a caliper.

Advanced options

For very small change, consider a microscope, optical comparator or wireless data logger. These capture tiny movement at short intervals and suit concrete or plaster pieces that need extra accuracy.

We provide engineering-led steps you can follow safely. If you need help, we offer free site assessments, fixed-price quotes and coordination of structural reports. Call Chris: 1300 970 930 or Email Chris: chris@underpinning-melbourne.com.au. Learn about costs with our cost calculator.

Reading the signs: width, direction, location and rate of change

Clear, simple signs give the best guidance. The key is repeatable readings that show genuine change rather than cosmetic hairlines. Note the pattern and keep records that highlight what actually changes.

Width versus length

Focus first on width. A small increase in width is a stronger sign of structural risk than a long, stable line. Widening points to ongoing movement and added stress in the fabric of the building.

Direction matters

Record the direction each time you check. Vertical or diagonal lines often reflect shrinkage or settlement. Horizontal lines are more worrying and can indicate foundation or load‑bearing issues.

Locations to watch

Pay attention to door heads, window openings, corners, ceilings and second storeys. These locations tie into the main frame of the home and often reveal meaningful movement.

Context and seasonal factors

Include temperature and recent rain in your log. Seasonal swings can cause repeatable shifts. If you see sticking doors, uneven floors or branching patterns, increase checks and consider expert review.

If readings suggest risk, we provide VBA‑compliant advice and permanent foundation solutions with minimal disruption. Keep measurements steady and clear so any required repair is based on solid evidence of crack movement.

Recording data and knowing when to call an expert

Keep a clear log that tracks each observation and every change over time. A reliable record makes later decisions straightforward and defuses uncertainty for homeowners.

Build a simple log

Note date, exact location, width, direction and temperature or humidity each time. Attach a square-on photo and reference the gauge or measuring method used.

Measurement cadence

Check daily after storms or heatwaves for a short period. If readings stabilise, shift checks to monthly, then every six months.

When to get help

Call us if you see widening, rapid changes, new shapes that run through door heads, or if doors or floors stick or slope. Such signs suggest a foundation issue or more serious movement.

Create one record per line: keep data orderly and consistent.
Use consistent measurements: for demec studs, zero the caliper, take several readings and average the distance.
Small elongation: silicone may suit cosmetic lines; widening needs an engineer.
Core services: Concrete Underpinning, Restumping & Reblocking, Resin Injection, Screw Piling and Wall Crack Repairs.

We are VBA registered and insured. We offer free, no‑obligation structural assessments, fixed-price quotes and council-compliant methods with minimal disruption. Book a free assessment: Call Chris: 1300 970 930 or Email Chris: chris@underpinning-melbourne.com.au.

Conclusion

A reliable method makes it easy to spot real movement rather than cosmetic change. Use tell‑tale gauges and the millimetre grid for X and Y reads. For discrete either side crack checks, demec studs with adhesive give accurate distance readings on concrete and masonry.

Seasonal swings can cause minor hairline changes. Widening lines or new sticking doors and uneven floors point at foundation or other structural problems and need prompt review.

We protect Melbourne homes with engineered, permanent solutions and VBA‑compliant certification. Book a free assessment or get a fixed quote via book a free assessment. Call Chris: 1300 970 930 or Email Chris: chris@underpinning-melbourne.com.au.

FAQ

What should I do first when I notice a crack in my Melbourne home?

Start with a safe, calm inspection. Photograph the area square-on, mark a discreet endpoint with clear tape or a pencil and date it. Record location, width and any nearby signs such as sticking doors or damp. If the crack is wide, has sharp steps, or the building is showing rapid change, contact a VBA-registered structural assessor immediately. Call Chris: 1300 970 930 or Email Chris: chris@underpinning-melbourne.com.au.

Why does movement matter for cracks in Melbourne houses?

Movement reveals whether a crack is an aesthetic fault or a structural issue. Widening or horizontally moving cracks often indicate foundation shift or soil stress. Seasonal changes and moisture can cause benign movement, but persistent change reduces structural integrity and property value. We assess direction, rate and location to determine risk and solutions.

When is it appropriate for a homeowner to carry out monitoring themselves?

Homeowners can safely monitor minor, stable cracks using simple methods when there are no sudden changes and no immediate safety risk. Avoid DIY measuring on large or rapidly changing fractures. If you feel unsafe or the crack appears to affect load-bearing elements, stop and arrange a professional assessment.

What are common causes of cracks in walls and foundations?

Typical causes include foundation settlement, clay soils expanding and contracting, moisture penetration, poor footings, ageing materials and thermal movement. Internal factors such as altered load paths after renovations can also start cracks. We consider soil type and local Melbourne conditions when diagnosing the cause.

Which basic tools are useful for reliable measurements?

Start with a tape measure, digital caliper, comparator cards and a clear plastic gauge. Use a level camera tripod for repeatable photos. For better precision, adhesive Demec studs with calipers or tell‑tale crack gauges provide repeatable readings. Keep measurements and photos in a monitoring log.

How do tell-tale crack gauges work and where should they be placed?

Tell‑tale gauges are fixed either side of a crack and show relative displacement on a printed grid or crosshair. Install them across the widest usable section, ensuring the substrate is clean and dry. Readings show direction and millimetre change over time, making trends clear without invasive work.

What are Demec studs and why use them?

Demec studs are adhesive measurement points bonded near the crack. You measure distance between studs with a caliper to track single-direction displacement very accurately. They suit small movements and are standard in engineering monitoring for repeatable, precise data.

Are advanced tools like wireless data loggers necessary for a home?

For most homes simple gauges, calipers and regular photos suffice. Wireless loggers and displacement monitors are useful for significant or accelerating movement, insurance cases or long-term engineered monitoring. We recommend advanced tools when precise continuous data is required.

How do I interpret width and direction of a crack?

Widening cracks are more serious than static hairlines. Vertical or diagonal movement often points to settlement or foundation rotation. Horizontal cracks in retaining walls or lower levels suggest lateral pressure or footing failure. We assess direction alongside location for accurate diagnosis.

Which locations should I watch most closely in a two-storey Melbourne house?

Pay attention to door and window heads, internal corners, chimney breasts, ceilings and second-storey junctions. These spots concentrate stress and reveal differential movement early. Keep photographic records and note if doors begin to stick or floor levels feel uneven.

How does temperature and humidity affect readings?

Temperature and moisture cause small, reversible movements in materials and clay soils. Record ambient temperature and recent rainfall with each measurement. Look for seasonal patterns before deciding on remediation. Sudden change outside seasonal norms needs prompt investigation.

What should a simple monitoring log include?

Record date, location, crack width, direction of movement, measurement method, ambient temperature and notes about recent rain or activity. Add photos named by date and position. Keep cadence consistent so trends are clear—this is critical evidence for engineers and insurers.

How often should I check and record measurements?

After a triggering event (heavy rain, nearby excavation, or strong storm) check daily for a short period. Otherwise, measure weekly for the first month, then monthly to six‑monthly depending on stability. Increase frequency if any acceleration occurs.

What signs indicate it’s time to call a structural engineer?

Call an engineer when cracks widen rapidly, horizontal displacement appears, doors and windows jam, floors slope noticeably, or multiple cracks develop simultaneously. Any visible rotation, gutter separation or step cracks at corners also warrant urgent assessment.

How can Underpinning Melbourne help with assessments and repairs?

We provide VBA‑registered, engineering-led assessments and permanent solutions tailored to Melbourne soils. We collect monitoring data, diagnose causes and propose underpinning or stabilisation if needed. Book a free assessment: Call Chris: 1300 970 930 or Email Chris: chris@underpinning-melbourne.com.au.