Frequently Asked Questions
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My house is cracking, what does it mean? When should I be concerned?
Some cracking damage to walls and/or the ceiling of a house can be considered normal, however the width, length and number of cracks appearing will determine if the cracking is considered within the normal range as defined by the Australian Standards or not.
The Australian Standard AS2870-2011 Residential slabs and footings gives guidance on the severity of cracking damage with reference to walls in Appendix C. Generally cracking damage less than 1mm in width is considered normal (depending on the total number of cracks in the vicinity of the subject crack).
An occasional cracking damage between 1-5mm in width is still within the “normal” range, however if more appear then it is considered abnormal
It is always a good idea to take a photo and note down the key features of the crack when it is discovered to monitor progress (better or worse). Things to note include width, direction, where it is located, if part of it is uneven or rotated. This information will be useful to the inspecting engineer to create a timeline of when the damage occurred and what events may have led to this damage occurring.
When you notice cracks in excess of 5mm or numerous cracks in the range of 1-5mm in the same vicinity, it is generally a good idea to have an engineer inspect and provide advice.
If I have plumbing issues that have caused cracking damage when could I expect the damage to disappear?
Plumbing issues generally add additional water to the soil, which can lead to expansion in clayey soils or consolidation in sandy soils. For clayey soils it will generally take 12-24 months for the soil to return to approximately the original equilibrium soil moisture content. Once the soil has returned to approximately the original soil moisture content the severity of the cracking damage should lessen and in some cases completely disappear.
It is important to allow time between the repair of damaged plumbing and the repairs of walls/ceilings, as early repairs can often lead to additional cracking damage as there is no room for the movement to reverse.
My house is in a bushfire area, what does it mean for timber constructions?
Your property will be given a BAL (Bushfire Attack Level) which will determine the severity of a bushfire should one ever occur.
The BAL level corresponds to a series of design/detailing constraints from AS3959-2009. These include particular types of timber, distances/lengths, construction methods and materials.
The lower BAL levels will generally allow the use of softwoods (MGP10/F7 etc) or LVL, providing specific conditions are met. For the higher BAL levels, softwoods will need to be protected by coatings or claddings. Or the use of hardwoods (F17/F27) can negate some requirements at a higher material cost.
If I have built a structure and missed an inspection by Council/PCA what do I do?
Firstly it is important to contact the inspector to find out the specific requirements, as it may be as simple as removing a sheet of gyprock, or digging a small hole adjacent a pad footing.
If the inspector requires an engineer’s certificate to certify that the works done are as per the plans/Australian Standards/Building Code, then Vision Engineers can help.
Typically to avoid destructive investigation photos and receipts of the construction can be used to determine the construction and materials used.
Vision Engineers may need to come out to site to inspect the structure or we may be able to provide certification based on the provided photos, it all depends on the structure and the inspectors requirements.
Council have asked for certification of my retaining wall/pool/other structure before I can get my occupancy certificate, what do I do?
You will need to engage an engineer to inspect the structure and provide a structural certificate confirming that the structure is constructed as per the plans/specifications and is fit for the intended purpose.
To aid this inspection, photos of the original construction works will be beneficial, even if they are pictures of the new dining table that you sent to grandma, which just happens to be next to the half built retaining wall.
If there is no available information on the structure then demolition works may be required to establish the construction details, such as removing a section of gyprock or excavating adjacent a retaining wall.
I want to remove a wall in my house, what do I need to do?
Firstly you need to determine if it is load bearing (i.e. supporting the roof or an upper floor); typically a builder/carpenter can confirm this for you.
On occasions it can be difficult to determine and may require localised demolitions to expose exactly what is going on. Sometimes it is possible to remove a light fixture and view into the floor space.
If the wall is non-load bearing then it can generally be removed, but there are a few conditions depending on the shape and length of the house, these are derived from the Australian Standards to ensure there is sufficient bracing throughout the structure. If the wall to be removed:
- Has any bracing (sheet or strap), this will need to be relocated onto an adjacent parallel wall. In this situation it is best to get an Engineer’s advice on the most effective way to do this.
- Results in the perpendicular wall being greater than 9m in length (depending on wind speed category), a minimum 450mm nib of the wall may need to be left so that it can be braced.
Where the wall is found to be load bearing specific engineering advice/design is required. In some cases a builder may be able to size the required beam from span tables or it may require and engineer to design the beam due to space constraints or non-standard loadings.