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How to extend existing concrete driveway?

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How to extend existing concrete driveway?


I’m looking for tips on how to extend my existing concrete driveway sideways by approximately 2m  wide and 7m long. My biggest concern is how I can ensure it won’t crack under the weight of our cars especially on the edges. Does anyone have any experience with this. As it’s only a relatively small area I was hoping we could do it ourselves.  

Bunnings Team Member
Bunnings Team Member

Re: how to extend your existing concrete driveway

Hi @nick626,


Expanding your concrete driveway is definitely achievable, and it's a project you can tackle yourself.


Start by clearing the space where you want to extend the driveway, removing any vegetation, rocks, or debris that may interfere with the concrete pouring process. It's important to have a clean and even surface. Excavate the ground below the current driveway and edging. Once the area is clear, compact the soil using a plate compactor to ensure a solid base for your new concrete. Make sure the soil is properly graded and compacted to avoid future settling or unevenness. Lay a 100mm layer of gravel as a base and compact it again.


When it comes to the edges, you have a couple of options. You can reinforce the connection between the new and old sections with reo bar, creating one cohesive slab. This involves drilling holes in the side of the existing driveway, inserting reo bar, and securing it with Chemset glue. These bars will extend out into the new area and be connected to the reo mesh for that section. Alternatively, you can use an expansion joint, which allows for natural expansion and contraction of the concrete due to temperature changes. This helps prevent cracks and ensures the longevity of your driveway extension. Using an expansion joint between the new and old sections would likely be the easier option for a D.I.Y. project.


For a step-by-step guide, check out our resource on How to pour a concrete slab.


If you have any questions, feel free to ask. Good luck with your driveway project!




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Re: how to extend your existing concrete driveway

Thanks MitchellMc for the advice. Much appreciated but can I ask how thick do you recommend the slab to be to handle the weight of vehicles and is there any special kind of concrete I should use for this job or do I just use general purpose concrete?  

Bunnings Team Member
Bunnings Team Member

Re: how to extend your existing concrete driveway

Hello @nick626 


It is required to adhere to the Australian Standards AS 2870 and AS 3600 when securing concrete slabs. The typical thickness range for slabs in Australia is commonly found between 85mm and 100mm.


Ideally, the recommended thickness for a driveway's concrete slab is approximately 100 mm. The key step is to prepare the underlying soil by removing large rocks and ensuring thorough compaction.


However, if you're anticipating heavy loads, such as a heavy-duty vehicle, additional consideration must be taken into account during the preparation process. In such cases, it is advisable to increase the slab thickness to 120 mm and apply a sealer to enhance its durability and resistance to damage.


It's also important to ensure that the driveway incorporates a slope to facilitate proper drainage of the slab. This ensures that water is effectively diverted away from the surface.


Let me just double check the type of concrete you can use on your driveway extension. As soon as I have the information, I'll post it here.


Let me tag @MitchellMc just in case he has any extra information to add.


If you need further assistance, please let us know.




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