Cracks in external brickwork are common in homes throughout Melbourne, but that does not mean they should always be ignored.
One of the questions we are regularly asked during building inspections is: “Are these cracks in the brickwork serious?”
The answer depends on the location, width, direction and pattern of the cracking, together with what is happening elsewhere in the building.
Some cracks may be relatively minor and associated with normal building movement. Others can indicate foundation movement, reactive soil conditions, drainage problems, deteriorated lintels or movement occurring around windows and doors.
The important thing is to determine why the brickwork is cracking, rather than simply filling the cracks and hoping they do not return
What Causes Cracks in Brickwork?
Brick walls are relatively rigid. When the structure supporting them moves, stress can develop within the masonry.
Eventually that stress may be released in the form of cracking.
Melbourne properties can be particularly susceptible to movement because many areas contain reactive clay soils that expand and contract as their moisture content changes.
Other factors that can contribute to brick cracking include:
- Foundation or footing movement
- Poor surface water drainage
- Leaking gutters and downpipes
- Reactive clay soils
- Large trees and vegetation
- Inadequate articulation or expansion joints
- Deteriorated or corroding steel lintels
- Changes or alterations to the building
- Localised movement around windows and doors
For this reason, an experienced building inspector should consider the entire property rather than assessing an individual crack in isolation.
Are Small Cracks in Brickwork Serious?
Fine cracking does not necessarily indicate a major structural problem.
Minor cracks may develop through mortar joints as a building naturally expands, contracts and settles over time.
However, the width of a crack is only one consideration.
A relatively narrow crack may still be important if it extends over a significant distance, continues through multiple courses of brickwork or corresponds with cracking and movement inside the house.
Cracking should also be investigated where homeowners notice that it is getting progressively wider.
What Is Stepped Cracking?
Stepped cracking is one of the most recognisable types of cracking in brick walls.
Instead of travelling in a straight line, the crack follows the horizontal and vertical mortar joints between bricks, creating a staircase-type pattern.
Stepped cracking can be associated with movement of the foundations or footings.
This does not automatically mean that the house has a major structural failure, but substantial or progressive stepped cracking should not simply be patched over without investigating the cause.
During a building inspection, we also look for other signs of movement that may support what the external cracking is telling us.
Cracks Above Windows and Doors
Windows and doors are common locations for cracks because openings create areas where stresses can become concentrated.
Cracking may extend diagonally from the corners of windows or doors.
Another possible cause is deterioration or movement of the lintel supporting the masonry above the opening.
Steel lintels can deteriorate or corrode over time, particularly where exposed to moisture. As corrosion develops, expansion of the steel may place pressure on surrounding masonry and contribute to cracking.
It is therefore important not to assume that every crack above a window is caused by foundation movement.
Drainage Can Contribute to Brick Cracking
One of the areas we consider when investigating cracking is the drainage around the property.
Water continually discharging close to foundations can alter the moisture content of the surrounding soil.
Problems may include leaking downpipes, blocked gutters, overflowing stormwater drains, garden beds against walls, poorly graded paving or surface water flowing towards the building.
In reactive soil conditions, significant differences in moisture around the foundations may contribute to uneven movement.
This is why examining the site surrounding the house can be just as important as examining the crack itself.
Trees and Soil Movement
Large trees can influence soil moisture levels, particularly during prolonged dry weather.
Tree roots can draw moisture from the surrounding soil. In reactive clay conditions, the resulting soil shrinkage may contribute to movement.
However, trees should not automatically be blamed for every crack.
The size and species of the tree, its distance from the house, soil conditions, drainage and foundation design should all be considered.
When Should I Be Concerned About Brick Cracks?
Cracking deserves closer attention when there are additional signs of movement.
These can include large or increasing cracks, substantial stepped cracking, separation around windows and doors, corresponding cracks to internal walls, binding doors or windows, uneven floors or gaps developing between building components.
Another important consideration is whether the cracking appears old and stable or whether movement is continuing.
A crack that has been repaired several times and continues to reopen may indicate that the underlying cause has not been addressed.
Can I Just Fill Cracks in the Brickwork?
Cosmetic repairs should generally not be the first step where significant or unexplained cracking is present.
Simply filling a crack with mortar or sealant may improve its appearance, but it does not necessarily correct the reason the crack developed.
If foundation movement, poor drainage or another building defect remains unresolved, the cracking may return.
The better approach is to first investigate the likely cause of the movement and then determine the appropriate repair method.
Cracks When Buying a House
Brick cracking is particularly important during a pre-purchase building inspection.
A freshly painted interior or recently repaired mortar can sometimes make previous movement less obvious to a prospective purchaser.
An experienced inspector looks beyond individual cracks and considers the property as a whole, including external brickwork, internal walls, floors, doors, windows, drainage, ground levels and other visible evidence of movement.
Where cracking appears significant or its cause cannot be determined during a visual inspection, further investigation may be recommended.
Professional Building Inspections in Melbourne
If you are concerned about cracks in the brickwork of your existing home or are considering purchasing a property showing signs of movement, a professional building inspection can provide valuable information about the visible condition of the property.
We inspect properties throughout Melbourne and assess cracking in conjunction with the surrounding building and site conditions.
Not every brick crack is a serious structural defect—but significant or progressive cracking should never simply be ignored.
The key is determining what caused the crack, whether movement appears to be continuing and what should be done next.
