A driveway poured without saw cuts or isolation joints
How new concrete cracks when nobody tells it where to crack.
In short: Handover reports in Cobbitty recorded driveway control joints never cut and isolation joints missing at the house slab.
Two findings, one cause
On one Cobbitty handover the driveway had no isolation joints where it met the house slab and pathway. On another, the control joint saw cuts had not been made. Both were recorded as major defects.
What a saw cut does
Concrete shrinks as it cures. A saw cut creates a weak line so the crack forms there, straight and hidden, rather than across the middle of the driveway.
What an isolation joint does
It separates the driveway from the house slab so movement in one does not crack the other.
Timing
Saw cuts need to be made soon after the pour. Left too long, the concrete cracks first.
What to ask for
Confirm that joints are cut and installed before handover, and note any cracking already present in writing.
Written by our local inspection team from work carried out in Cobbitty. Licensed building practitioners, NSW Fair Trading licence 366177C.
