How to lay slab for shed?

[SheriBobbins]

How do we go about putting up a shed on a slab?  We're after 3x6m shed, but we dont know if we should lay the slab first or after it's been put up.  I have heard both options work.  Does anyone know?  It's not for a car, so just a regular 3x6m back shed.  We would also like another 2m of concrete paid on one end of the shed as an outside workshop area.  Would this change the plan that you had in mind? 

Another minor question is, our backyard gets quite soggy with alot of rain.  Should we build up the ground a bit where the shed is going so we dont risk it flooding? 

Thanks

[JacobZ]

Hi @SheriBobbins,

Welcome to the Bunnings Workshop community, it's great to have you with us.

A shed the size you are looking to install should definitely be placed on a strong, level concrete base. This will allow everything to be assembled level and plumb with adequate anchoring to prevent it flying away in heavy wind.

I'd advise contacting a local concreting company for a slab of this size. Small slabs are certainly manageable with basic tools, but a slab of this size can rapidly go wrong if you aren't prepared and don't have the right tools and knowhow. You might like to have a look at How To Pour A Small Concrete Slab for what is required to pour a small slab. Keep in mind that this slab is roughly 600mm x 1200mm and is far more manageable with some basic concreting tools. You could look for a concreter in your area to quote on this project using something like Hipages or True Local.

A concreting company could help you prepare the compacted foundation for the slab, install drainage around the outside, install the formwork, add steel reinforcing, pour and finish the slab to a professional standard. I'd be concerned that attempting a slab of this size without prior experience could go wrong very quickly and then you'd be out of pocket considerably.

Let me know if you need further guidance.

Jacob