pour a new foundation?

[matty]

Hello everyone... this is my first post so be easy.

I visited my relatives in italy and I fell in love with the pizza oven they had in the backyard! I am looking to build one in my backyard now and need some input. I have a basketball court which is poured in 4 10x10 squares of appx 3 inches of concrete and I didnt use rebar when pouring. I want to build the oven on top of one of the squares but I am worried the slab might crack under the pressure?

any thoughts would be appreciated.

thanks!
Matty

[Les]

Re: pour a new foundation?

Matty - what is your soil like? If it is sand / DG, you may be good. If you are sitting on clay - that would be bad. In your location, you can occasionally experience a freeze. I personally would cut out the area for the oven and re-pour. It's really not that big of a foot print. The bigger question is, how in the hell can you play hoops when there is an oven in your way?

Les...

[nissanneill]

Re: pour a new foundation?

Hi Matty,
irrespective as to what is underneath the cement slabs, I would locate the position and size of the proposed oven, cut out a 12" wide section with a diamond saw (or get it cut professionally or simply hire a petrol saw) and dig a substantial deeper beam foundation with adequate reinforcing bar.
I would also drill sideways into the cut cement slab and drive some 6" pieces of reinforcing bar every 2 ' to tie the new beam footing to the slab.
I know it is a lot of trouble BUT how would you live with the problem of cracked and possibly listing (although only slightly) your cracking badly slab which after all was placed and strong enough the run, jump and play upon. Now you are tempted to put at least a ton of blocks, cement slab and bricks on a 5" x 6' section.
Play safe and do it properly first time!

Neill

[Breven]

Re: pour a new foundation?

I agree. In fact, I had to cut some concrete out to pour a nice thick rebar reinforced slab with a footing. I used my skill saw and a $15 concrete blade from home depot. Just run your hose next to your balde as you cut- it goes right through. Then, grab the sledge hammer. I took all the bits of concrete and stacked it up next to the garbage can. Each week I tossed a couple of chunks in the can until it was all gone. Worth the extra effort though to know you are building on a solid foundation.

[bluespider55]

Re: pour a new foundation?

Pretty well covered already.
I would definatly cut the slab and pour a proper foundation my only input would be to underpin the existing slab. That way the new foundation would support the cutout in your old slab. Also if you create any internal corners by removing a section of the slab, as i presume you would. A saw cutt back on a 45 degree through the remaing section of slab will give the slab an expansion joint for movment or a controlled crack.

Hope you can understand my explanations.

Phil...........