Any mention of cracks in a Building Inspection Report may cause fear and panic for a property buyer. However, you may be surprised to know that cracking is seen in most buildings at some point in their lifetime.
Cracks appear for a couple of reasons:
- The materials age and the building eventually settles down, conforming to the environment in which it is built.
- The builder has not installed expansion/control joints to accommodate the settling down of the building into its environment.
Are cracks in buildings serious?
Contrary to the fear that it creates, cracking in buildings is usually not serious. In most cases, cracking only spoils the appearance of a building. Typically, you can easily repair those types of cracks.
However, cracks can also be a serious threat to the stability and serviceability of the building. Therefore, whatever the type of crack, you should treat it seriously and report the matter to the relevant authority as soon as the crack is spotted.
You can also make sure that it is investigated thoroughly by a structural engineer. The cause of the crack and its seriousness can be established, in some cases, only through monitoring consistently for a long period, sometimes over many years.
What causes building cracks?
It is important for you to know that cracks in buildings appear as a result of many possible factors:
- Age of the building.
- Construction of the building.
- If the building has been altered structurally or there are new extensions, additions etc or part of the old structure has been demolished.
- If the nearby landscape has changed, including planting or uprooting of large trees, or other disturbances have affected the nearby soil etc.
Where do most cracks appear?
You will find most cracking happens in weak spots such as wall junctions and between window and door openings, and in such cases it is important that your building inspection report reveals the severity and the extent of the cracks.
Various materials used for construction respond in different ways to stress which may eventually lead to cracking of the building walls.
The building inspection report may list various types of cracks
Different types of cracks can appear in a building. When you identify cracks that appear on a building, it is equally important that you also determine the age of the cracks.
If the cracks are old, the chances are high that they are now filled with debris. If the crack tends to taper, it may be inferred that while the building has moved, these types of cracks also indicate doming of the slab.
Slab dishing occurs when hydration and dehydration occur in clay soils. Cracks formed due to shear forces often collect debris on one particular side of the crack. Occasionally, compression is yet another reason for the formation of cracks.
Progression of cracks and their impact
Once you spot cracks, it is important to keep an eye on them to find out whether the cracks are changing over time or are stable. A crack that was initially small but progressively changing may indicate that the building’s structure has experienced movement. This may require remediation.
The monitoring should continue during the period of remediation and afterward. This will tell you how effective the repair has been. You may need to make some adjustments in the post-remediation period.
You can decide the remediation method after a thorough study of the nature of the crack and what caused it. Sometimes, there are many causes in combination that cause the cracking.
Cracks may also alter the functioning of the building such as compromised waterproofing or sticking windows and doors. In such cases, you may also have to carry out secondary repairs.
As you can see, some cracks may be superficial and may be fixed with minimal disruption and expense; other have serious and costly consequences. A thorough pre-purchase building inspection report will give you the facts and help you decide whether to go ahead with the property purchase or walk away.
Cracks – Australian Standards
As per the QBCC Standards and Tolerances 2016 Guide, and the Australian Standard – AS2870, it is relevant for you to know that any crack that occurs in concrete slabs that are 2 mm or greater in thickness and on plasterboard walls that are 5 mm or greater in thickness (3 mm or greater when they occur in groups) are deemed as defects.
Hire an experienced Building Inspector
An experienced and knowledgeable inspector will able to study and understand the type of defect and determine whether:
- the crack only affects the appearance or is just a blemish
- it is a serviceability defect that affects the building’s functioning and can be repaired, such as waterproofing and sticking doors and windows
- the crack is a serious structural defect that may affect the building’s stability.
Structural defects may be only as wide as 0.1 mm. It is also possible that cracks wider than 5 mm are nor structural in nature. Cracks found in structural elements may themselves not be structural in nature.
The other factors that the Building Inspector assesses include the location of the property, and also the building’s function. The extent of cracking, their severity and the degree of progression are other factors that are studied.
The Building Inspection Report should identify and list the cracks defined as defects as well as their extents and severities.
Recommendations as to the actions to be taken should also be included, such as whether monitoring should be continued or whether the cracks should be promptly reported to a structural engineer for further investigation.
The most important point is that you should take the recommendations and advice seriously and implement the changes within the suggested time frames if you choose to proceed with buying the property.
The bottom line is that you need to arrange a Building Inspection Report to gather the facts about the relative seriousness of any cracking in the building before you make a decision to buy the building.