Oven base installation on existing (uneven) patio

[s988rt]

Hi all,

I'm new to the forum and just beginning my pizza oven installation (process).

Question for you all: I would like to install the oven (42") internal width on an existing patio adjacent to an existing BBQ island. The existing patio is 1 inch sandstone mortered in place on top of 3 inches of rebar reinforced concrete (correctly installed) both are installed at an approx: 5 degree angle to drain water away from the house. [See attached photos]

I would like to install the base of the oven as depicted however need a suggestion for how I should treat the existing concrete and sandstone base. Should I remove the sandstone and install a further 2 inches of concrete on top of the existing concrete and plumb to level for the pizza oven? Any suggestions?

Thanks, Steve

[GianniFocaccia]

Re: Oven base installation on existing (uneven) patio

If it were me, I'd leave that great-looking sandstone in place and gradually make up the 5degree slope with mortar between courses. Once the cores are filled you're good to go.

[BriggsARNP]

Re: Oven base installation on existing (uneven) patio

I agree. I don't think that the sandstone will have any problems supporting the oven if it is already on a solid concrete base.

[chidding]

Re: Oven base installation on existing (uneven) patio

Agreed with above..

In regards to the level.. either level it from the first block.. or once you poor the reinforced concrete top.. correct the level there..?

[s988rt]

Re: Oven base installation on existing (uneven) patio

Thanks everyone for your replies.

I've found the sand stone to "flake" a bit on the surface layer due to weather and the very porrus nature of the stone.

Do I need to worry about a heavy oven on top or will the weight of the oven and the fact that the sand stone is covered in cinderblock keep it from deteriorating?

Thanks! Steve

[brickie in oz]

Re: Oven base installation on existing (uneven) patio

You could always mark out where your oven is going and cut through the sand stone down to the concrete.

If you do cut out allow 10-20mm all around for some jiggle room which you can later mortar up.

It looks like some of the sandstone has moved previously as there are cracks around the mortar pointing between the stones.

[Neil2]

Re: Oven base installation on existing (uneven) patio

Your sandstone sections will likely crack.

As Brickie suggests, I would cut them back at the line of the new block wall. This can be done with either a masonry blade on a circular saw or (preferred) a masonry blade on an angle iron (keep the stone wet).

You can then leave the sand stone under the walls or remove then as you prefer. I would think that your existing base is more than adequate to support the proposed oven.

[s988rt]

Re: Oven base installation on existing (uneven) patio

Thanks everyone, appreciate the insight.

[Pizza Fermentor]

Re: Oven base installation on existing (uneven) patio

I have a similar situation as above. I have decided to construct a 4' square cinder block base on my brick patio. The patio is have been throug 6 Ohio winters, so it has settled as much as it's gonna.

Rather than place the block directly on the bricks, I bought nine 16" x 16" x 2" concrete squares and laid them on top of the brick. I figure this will help distribute the weight over a larger area and help alleviate my concerns that the brick might sink.

Initial layout of the cinder block atop the 9 squares revealed a tiny bit of wobble. I assume this would go away once the cinder block holes are filled with cement and the top cement form is applied.

The patio slopes left-to-right for drainage purposes. Thus the left cinder blocks are 1/2" higher than the right side. Is this a big deal? I could correct it on the 1st row, or on the top form...or keep it at 5 degrees (maybe water running off the top slab is a good thing?).

Anyone done something like this before? Am I an idiot?

Wednesday is when I start pouring cement down the block holes. Any input is really appreciated.

[dmun]

Re: Oven base installation on existing (uneven) patio

Your oven is very heavy. It will compress your brick patio, particularly if the bricks are laid on sand instead of stone dust. I'm a little concerned that uneven settling under load, combined with dry stacking of your blocks may create a problem down the road.

Are you space constrained? Why are you building on a finished patio, instead of pouring a proper slab next to it? Brick patios aren't cheap, I'm wondering why you are covering it up.

[Pizza Fermentor]

Re: Oven base installation on existing (uneven) patio

The patio has a crushed gravel base, and is circular. It's surrounded on 2 sides by my house, and on another side by fencing. The open side, for entry/exit is only about 5 feet wide. There's no place outside the immediate circumference of the patio to add a cement slab.

Only 4ft square, it fits perfectly on the patio, where I'd be using it the most. It would look great there too. If it isn't located on the patio, I'd need to stick it in the back yard. I'd rather not do that.

But -- a crumpled pile of cinder blocks with an oven on top wouldn't look great on my patio either.

[Neil2]

Re: Oven base installation on existing (uneven) patio

I agree with Dmun.

The possibility of differential settlement is a concern. I suggest you take up the brick where the footprint of your oven is proposed and pour a reinforced slab.

[Pizza Fermentor]

Re: Oven base installation on existing (uneven) patio

I agree with Dmun.

I suggest you take up the brick where the footprint of your oven is proposed and pour a reinforced slab.

If I tore out a section of the patio, I think my wife would kill me and cremate my body in the oven. With a 28" i.d., it might take her a couple days...but she'd do it.

Looks like I may need a Plan B. I did place a call to the guy that built the patio to get his thoughts. But if he says "Go ahead and build on the brick," he'll be the first guy to do so. Everything I can find tells me otherwise.

[Pizza Fermentor]

Re: Oven base installation on existing (uneven) patio

After a massive survey, I have resigned myself to keeping my patio in-tact and installing a slightly-bigger-than-4ft cement slab next to my patio. Unfortunately this poses 2 problems --

1.) The patio is round. Anyone have a nice method of abutting a cement slab next to a round, brick patio?

2.) The patio slopes down to the ground immediately after its edge. The ground is probably 2 feet below the patio surface. Is anyone familiar with a method of creating an "elevated" thick slab to meet level with my patio surface? Should I build a mortared cinder block frame and fill it with 2.5 feet of cement atop a gravel base? How deep would the gravel base need to be? Vertical rebar on the inside support it?

Thanks for the guidance, everyone. You probably saved me a damaged patio and oven. That would have been a major downer.

[Neil2]

Re: Oven base installation on existing (uneven) patio

"Anyone have a nice method of abutting a cement slab next to a round, brick patio?"

Have you considered building it on piers ?

http://www.fornobravo.com/forum/f21/...ucer-3033.html

Or the nice one George (Fxpose) did:

http://www.fornobravo.com/forum/f21/...ome-12677.html