# Forum Home Renovation Concreting  Garden Shed Slab - Newbie needs help!

## dammit

I am about to tackle my first concrete slab and need all the help I can get  :Smilie:  
It will be 3m by 2.3m in size. 
I am laying it right near where there is a sewer line (no other suitable spot unfortunately). There is a manhole literally 50cm away so shouldn't be a big deal. Anyway because of this I am thinking of making it 90mm thick with no reo. Given it is just a garden shed it doesn't matter if it had any little cracks in it etc. Only storing general garden tools etc in it. 
Our soil is class S slightly reactive, but really it is pretty much general soil, little bit clay'ey. So should I dig out so there is say 60mm deep hole and then the slab will sit 30mm above ground level? Is that enough? 
Do I need to put a layer of sand down or crushed gravel and then compact it? I really want to do this on the cheap and easy and have no real way to transport sand and stuff so hopefully I can get away with not using any of that stuff and just pour the concrete straight on top of the soil. 
Do I need to lay a sheet of plastic down before pouring the concrete? Is this necessary? Is a specific plastic type needed? 
I am going to get boral to deliver the concrete, they have priced me 20-20 mix - I'm not too sure on all the jargon but will this do? Do I need to ask for any specific concrete in particular? 
With my formwork, I was planning to just use standard 4x2 wood, and make a frame and nail it together, then maybe put 1 or 2 wood stakes in half way along the way. 
The shed instructions say to do a rebated edge 50mm on every side. It showed a picture of attaching another bit of wood to the top of your formwork so when you pour the concrete it will achieve the rebate for you. Is that what I should do? Should the rebate just be say 45mm step down from the main slab? 
When they deliver the concrete I am guessing it will take me about 6-8 loads of the wheelbarrow. Would 1 person be able to do this many in the standard 15 min delivery time? It is about a 20m flat walk from the truck to the slab area. Will it allow me enough time to get the thing set up and screeded before drying if it is a 35 degree day, how long will I have to work? 
My calc's say I will need 0.62m3 of concrete with a 90mm thickness, they can either deliver 0.6 or 0.8. Will I be able to get away with 0.6? Maybe just go a little thinner if I don't have enough? 
Is there anything I have forgotten or any tips someone can give me?? Sorry for so many questions but because I will be doing this alone and it is my first time and I have no experienced concrete mates to help me out, hopefully I can get all the info I need here  :Smilie:

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