What Size Should a Shed Concrete Slab Be?
Getting the slab size right matters. Too small and you lose usable floor space. Too large and you're paying for concrete you don't need. Whether you're planning a garden shed base, a concrete pad for a shed or a larger concrete floor for a workshop or garage, here's how to think through the dimensions before you request a quote.
Request a shed slab quoteMatch the slab to the shed
The most common approach is to pour the slab to match the exact footprint of the shed kit. Most kit sheds come with a specified floor size, so start there. If your shed supplier has specific slab or base requirements, check those before requesting a quote.
If you haven't chosen your shed yet, work backwards from how you plan to use the space — what needs to fit inside, whether you'll work in it, and whether you need room to move around equipment. A shed with a concrete floor needs a slab that suits the shed's use, not just its footprint.
Common shed slab sizes
These are rough guides only. Your actual slab size should match your shed and site.
Garden shed
3m × 3m to 4m × 3m
Basic storage, mower, garden tools.
Single garage / workshop
6m × 6m to 6m × 9m
One vehicle or a workbench setup.
Double garage
6m × 9m to 9m × 9m
Two vehicles with some storage.
Large farm or machinery shed
12m × 9m and above
Tractors, trailers, or heavy equipment.
Should the slab extend past the shed walls?
Sometimes yes. A small overhang at the front (say 300–600mm) can give you a dry entry point or somewhere to stand tools. Whether this makes sense depends on your shed design and how you'll use the space. It's worth mentioning when you request a quote.
Once you've settled on a size, the next thing to think about is thickness. See our guide on how thick a shed slab should be for what the common options are.
What to include when requesting a quote
- Approximate slab length and width in metres
- What the slab is for
- Your suburb
- Whether the ground is flat, sloped, cleared or unprepared
- Whether there is easy access from the driveway, street or gate
- A photo of the slab area and a photo of access if you have them
Related shed slab guides
Save this quick guide
Save this card to your phone so the key points are easy to find later.
What Size Shed Slab Do I Need?
Match the slab size to your shed footprint.
Common slab sizes
- Garden shed: 3m × 3m to 4m × 3m
- Single garage or workshop: 6m × 6m to 6m × 9m
- Double garage: 6m × 9m to 9m × 9m
- Large farm or machinery shed: 12m × 9m and above
Allow 300–600mm overhang at the front if you want a dry entry point.
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What Size Shed Slab Do I Need?
Match the slab size to your shed footprint.
Common slab sizes
- Garden shed: 3m × 3m to 4m × 3m
- Single garage or workshop: 6m × 6m to 6m × 9m
- Double garage: 6m × 9m to 9m × 9m
- Large farm or machinery shed: 12m × 9m and above
Shed Slab Ballarat
shedslabballarat.com.au
Download this guide card and save it to your phone. It's a handy reference when you're ready to call or fill in the quote form.
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Share your shed size, suburb, access details and optional photos so we can understand the job before calling you back.
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