Installing a concrete slab on your property can add extra utility, but before beginning excavation it’s essential that you contact the local 811 Call Before You Dig line first to have it marked for critical underground services.
To avoid cracking, start with a well-draining base of road base or crusher dust and compact it firmly using a rental plate compactor.
Digging
Before pouring a concrete slabs Melbourne, the ground must first be prepared by clearing away rocks, debris, or vegetation in the area and marking its location with stakes and string. If your site slopes downwards, additional measures such as building up one side of the slab or adding a low retaining wall may also be necessary to achieve success.
If your slab will serve as a foundation, a gravel subbase should be laid first to provide support and prevent cracking in the concrete. You’ll also want to check with your local building department regarding permits required and how close you can build to the property line.
Pouring your slab should be completed on a warm and rain-free day to minimize delays and ensure optimal conditions for concrete setting too quickly without cracks forming in its curing process. Any rain anticipated could slow work significantly or force too early of a setting time for settign too soon causing too rapid setting and further delays to set in its curing time, potentially increasing costs further still.
Filling
Once your slab is in place, there is only a limited window of time before it begins setting. Mix sand-cement grout in a wheelbarrow, and pump it into any voids under the concrete using a slab jacking pump at 10 PSI – this allows affordable void penetration while creating stronger slabs.
Void filling is essential in correcting problems related to erosion, sinkholes, or structural defects with house foundations or sidewalks. Numerous factors contribute to soil changes causing voids underneath concrete surfaces such as plumbing leaks, extreme weather events and burrowing animals causing changes.
After sanding down the form boards with a hand float, cut two long side form board stakes three inches longer than slab length and nail four-foot 2×12 cleats onto them. Attaching both long side form board stakes using 16d duplex nails ensures proper support of bracing structures.
Forming
To prevent wet concrete from sinking as it sets, you will need to reinforce its surface with reinforcing bar or wire. Rebar can be purchased pre-cut lengths and secured together using wrapping tie wire. In addition, plastic membrane should cover the entire area so as to keep moisture out and prevent seeping through concrete.
Plant stakes at each corner where your slab will sit, then use a line level and builder’s level to make sure the site is squared off properly – this will help the concrete settle more evenly in all directions.
Spread and compact three-inch layers of granular fill over stakes to form the firm foundation for your concrete slab. If you live in a cold climate, footers may also help support it to prevent frost heave or breakage of the slab from frost heave.
Pouring
Once the compacted base and form have been assembled, it’s time to pour concrete. This stage can be physically demanding; speed is essential to prevent too rapid curing. Therefore, having several helpers handy at this point may prove invaluable in getting this job done faster.
Mix your concrete using a mixture of one part cement, two parts sand and four parts coarse aggregates. Be sure to use a dry, clean mixture – adding small amounts of water may make the mix more workable if necessary.
Once the concrete has been poured, use a screed board or bull float to smooth it before it sets. A screed board may also help level out and create a uniform surface before curing for one week; then it should be ready for use if supporting buildings or located in areas prone to frost requires footers around its edges.