VBA registered and insured, in Geelong since 2006
All concrete moves a little as it cures, so the honest answer is that we control where it cracks rather than promise it never will. Why control joints cut at the right spacing send shrinkage cracks to the joint line, why a skimped base cracks across the middle, and why the slab and footings are the part we guarantee.
Will it crack is the fear under every concrete job, and most quotes dodge it. The honest answer is that all concrete moves a little as it cures, so the real skill is controlling where it cracks, not pretending it never will. Here is how that is done, and why the base, the reo and the joints are the part we stand behind.
Concrete shrinks slightly as it cures, and the ground underneath moves with the seasons. So a slab with no plan for that movement cracks wherever the stress lands, usually across the middle. A slab built right cracks too, but on a line you chose and cannot see. Controlling the crack is the job. Promising no crack is the sales pitch.
Get those three right and the slab is still flat and crack-free in ten years. Skimp any one of them and the slab cracks across the middle, which is exactly what the cheap pour does to save a few dollars you cannot see being saved.
A crack on the joint line is the slab working the way it was built to. A crack across the middle is the base, the reo or the joints being skipped. We do not save money below the surface, where you cannot see it.
We guarantee the slab and footings for 10 years in writing because that is the part we control: the compacted base, the reo sized to the soil classification, and the control joints cut at the right spacing. If the slab cracks from a skimped base or footing in that time, we put it right. That is the concreting-specific lever, and it is the one a cash job with no guarantee in writing cannot offer.
Ask this, exactly
“How will you control where the slab cracks, what spacing will the control joints be cut at, and does the 10-year guarantee on the slab and footings come in writing?”
A concreter who explains control joints and guarantees the slab and footings is one who controls the crack. 'It will not crack' with nothing in writing is the answer that ends in a slab cracked across the middle and no one to call.
We compact the base, size the reo to the soil, cut the control joints at the right spacing, and cure the slab so it reaches its strength instead of drying out and cracking. Then we hand over the 10-year slab and footings guarantee in writing, with the AS 2870 paperwork where the slab is structural. So the answer to will it crack is one you can hold us to, not one you have to take on trust.
Slabline Concreting Co.