Concreting FAQs, Bendigo

A handful of things, and none of them can be judged from your kitchen table. The first is the area in square metres, since a bigger pour uses more material and more labour. The second is the finish: plain concrete is the simplest, while exposed aggregate, coloured and polished finishes add process and cost more. The third is what is already there, because breaking out an old slab, carting the rubble away and excavating a proper base all take time before a single wheelbarrow of new concrete arrives. The fourth is access, and the last is the ground itself, which in Bendigo can mean reactive clay or disturbed mining fill that needs a different base. That is why every job needs a site visit. Ring us with your suburb and roughly what you want done and we will get a local concreter to come and price it properly rather than throw you a number that changes the moment they turn up.

Both are common around the older Bendigo suburbs and both matter. A sloping block changes how the concrete gets from the truck to the formwork. If a truck can back up and chute straight in, that is the quickest and cheapest way. If it cannot, the mix has to be pumped or barrowed, which means more people and more hours. A sloping site can also need extra formwork, steps or a stepped pour, and better thought given to where the water runs. A tight block behind a period home limits access the same way. A concreter who works your area already knows which of these applies before they arrive.

It can, and it is the single biggest local thing to be aware of. Bendigo is one of the great gold-rush cities, and many older areas, Long Gully, California Gully, Ironbark, Eaglehawk and Golden Square, sit over historic mine workings, old shafts and disturbed fill. Ground like that can settle unevenly under a slab if it was never assessed and the base built to suit. It is not exotic to deal with: it comes down to checking the ground before footings and slabs go in, and building the base and steel to match what is underneath. For a habitable slab an engineer's soil assessment covers it off. A concreter who works those suburbs allows for it without being asked.

A lot. Much of the region sits on reactive clay, and around the fringes there is gravelly ironbark-forest ground, both of which move with the seasons, swelling when wet and shrinking when dry. That movement is what cracks a slab that was not built for it. The answer is engineered footings, correct steel, sensible joint spacing and articulation so the slab can cope with the ground moving under it, plus good drainage so water is not feeding the movement. The slab is matched to the soil classification of your block, which is why a site visit matters.

Sealing is not compulsory but it earns its keep, particularly on decorative and exposed aggregate finishes. A sealer slows staining from oil, leaves and general traffic, keeps colour from fading as fast, and adds a barrier against the strong summer sun that ages an exposed surface. It is not permanent. It wears off over time and needs redoing periodically, and how often depends on the product used and how much sun and traffic the area cops. Ask your concreter what they have put down, because the product determines the reseal interval, and there is no single answer that fits every job.

The slab sitting on your own land generally does not need approval, but the part where your driveway crosses the footpath and nature strip to meet the road, the vehicular crossing, does need approval from the City of Greater Bendigo, and the council has its own specifications for how it is built. That covers the width, the profile, the materials and how it ties into the kerb. Stormwater and drainage can also come into it on some blocks where water has to go somewhere sensible. A concreter who works Bendigo will usually know the local requirements and how to arrange the crossing, but the approval itself sits with the council, so it is worth raising early rather than after the pour.

Walking is usually fine within a day or so, once the surface has hardened enough not to mark. Driving is a different matter. You should generally keep cars off a new driveway for about a week, and heavier vehicles such as trucks, caravans or a loaded trailer for longer again. Concrete keeps gaining strength for weeks after it looks finished, so the surface being hard underfoot does not mean it is ready to carry a car. Your concreter will give you a specific time based on the mix, the thickness and the weather on the day. In a cold Bendigo winter the reaction that hardens concrete runs slower, so a winter pour will sit at the longer end.

Both ends of the Bendigo year need managing. In the hot, dry summer a fresh slab can lose moisture too fast, which weakens the surface, so pours are done early in the day and the slab is cured to keep the moisture in rather than letting it flash off. In winter the cold slows the set right down, and a concreter will not pour into a frost because concrete that freezes before it sets is damaged. Rain is the other one: water landing on a fresh surface before it has set can weaken and mark the finish, so pours get postponed when the forecast is poor. A concreter who reschedules you because of the weather is doing right by your slab.

All concrete cracks to some degree. It shrinks as it cures and it moves with temperature and ground conditions, and it has very little ability to stretch. The job of a good concreter is not to stop cracking outright, which cannot be done, but to control where it happens using control joints, correct steel and a properly compacted base. Fine hairline cracks are normal and cosmetic and are nothing to lose sleep over. What is worth a look is a wide crack, a crack with a step or height difference across it, or a crack that keeps growing, because those usually point to something moving underneath, reactive clay, disturbed mining ground, or drainage that has failed. If you are seeing that, get someone to look at it rather than filling it and hoping.

It depends entirely on what is going on top of it. A residential driveway carrying cars is typically around 100mm with reinforcing mesh through it. Anything carrying heavier loads, a truck, a caravan, a boat trailer or an industrial hardstand, needs more thickness and heavier reinforcement. Ground conditions change it too. Reactive clay and disturbed mining fill can call for a different approach than a stable pad. Your concreter should specify the thickness and steel for your particular job rather than pouring a default, and it is a perfectly fair question to ask when they quote you.

Often, yes. If the existing slab is structurally sound, not badly cracked and has not dropped or moved, resurfacing is usually cheaper and faster than demolition and a fresh pour, and it saves you the mess of breaking the old one out. If the slab has deep cracks, a step across a crack, or ground that has settled underneath, an overlay just puts a new surface over the same problem and it will come back through within a season or two. Someone needs to stand on it and look at it to tell you honestly which situation you are in. It is one of those calls that cannot be made from a photo.

The whole region. That runs from Kangaroo Flat, Golden Square and Flora Hill in the south, through the central heritage suburbs of Quarry Hill and Ironbark, up to Eaglehawk, California Gully, Long Gully, Epsom and White Hills, and east to Strathdale, Strathfieldsaye, Junortoun and Kennington, plus Maiden Gully and Marong to the west. Our suburbs page lists everywhere we work in detail.