Concrete base advice

[Pulp]

Hi,

I'm currently planning an outdoor oven for next spring time and have seen the one I want (buying a pre-fab) but need to build a base. This thing weighs 400kgs so I'm guessing I need to put a slab down that will support this plus the brick walls to take it to a height I can use, so that's going to be the best part of 5-600kgs it will need to support.

It will be approx 2 meters long and 1.5m wide - any ideas/advice on thickness and if I should put some metal support inside, such as this type of thing:

http://www.travisperkins.co.uk/ROM-Concrete-Reinforcement-Steel-Fabric-A142-Mini-2-42x1-22m/p/302415

Do I need to pay the slab on anything other than bare earth? As you can tell I've not done this type of thing before, so need a 'dummies guide'.

Thanks

 

[Halitosis]

I'm certainly no expert, but dug and poured foundations for a retaining wall. The lessons I learned (including countless hours of internet research) led me to believe that 12 - 18 inches depth is usually enough for anything short of a house, though width/depth is also important (extending at least 12 inches beyond the wall/oven front/back and each side). Ensure the base of your trench is firm (if previously undisturbed then it should be well compacted anyway - just don't dig beyond and then fill back in loose).
Although probably unnecessary, I bought some rebar (look on gumtree or ebay for leftovers) and supported it a few inches above the base of the trench (on parts of bricks) before pouring the concrete. For straight sides and a clean edge to your concrete, build some 'formwork' out of timber for the top few inches (or whatever is above ground).
Buy a cement mixer, all your materials, a couple of buckets (to measure quantites), and a wheelbarrow, then mix and pour your concrete in a single session (generally, the dryer the mix the stronger the resulting concrete). Finish the surface with a piece of timber, hose down and sell your mixer to the next DIYer, and job's a good'un!
Youtube is a great resource, as is http://www.pavingexpert.com/
Once you've done it once, you realise it isn't rocket science.
Oh, one other thing I learned was that my mixer needed to be stable, with plenty of weight holding it steady around the feet/stand - it fell over and threw my first load over the driveway and front lawn!

 

[Pulp]

Hi, thanks for the reply. I was talking to a guy who has put a 700kg bbq on a 4 inch base - he's had that down for 2 years with no issues... so far.

 

[r896neo]

500kg is not a lot in the scheme of things. If you put down a raft, the depth of concrete is less important than the quality of the ground or base as its less likely to crack than it is to lean.

If it was me I would dig out the area and put down 4 inches of compacted hardcore and a 150mm reinforced concrete slab. That would be plenty, probably slight overkill but rather that than wonky and its such a small area it wont be too difficult or costly.

12-18 inches is flat out bonkers