Build stand into a retaining wall

[stlouisz]

I have been trying to decide on the location to build my oven. I have a tiered retaining wall around a paver patio. I have included a couple cross sections of our wall and a couple pictures.

Ideally, I think the best location is to build the block stand in place of a section of the front retaining wall. However, the block stand would then have to function as a retaining wall.

In the section where the second (back) retaining wall tapers to one course of blocks, can I remove a section of the front retaining wall, build a floating slab, and build the stand using blocks in front of the back wall?

If so, can I leave the back wall alone, or might I have to rebuild it so that I have four rows of block? The overall height elevation is probably close to 36".

Thanks

[texman]

Re: Build stand into a retaining wall

look at deejayoh thread in the same getting started section. Also Amac tackled this as in his build. whttp://www.fornobravo.com/forum/f6/s...ild-16994.htmlell. hth
Tracy

[stlouisz]

Re: Build stand into a retaining wall

Thanks for the quick reply. I actually did see those posts when I was searching for similar design scenarios.

Their layouts are different and their hearth heights were at the level of the retaining wall, so Amac appears to have put his at grade behind the wall.

My front wall is only 26" high. Even if it were high enough, there is neither enough space or a stable method for putting the hearth between the two retaining walls.

[GianniFocaccia]

Re: Build stand into a retaining wall

I had a similar situation and am really glad that I put the oven behind a retaining wall and out of the way. Here's how I did it:

http://www.fornobravo.com/forum/f8/octoforno-7122.html

John

[stlouisz]

Re: Build stand into a retaining wall

John,

Your situation does look very similar. It looks like you have the foundation slab top in line with the top of the first course of the wall.

My first design idea was similar, but I was concerned about using the front retaining wall as a support. It looks like you have two thick concrete slabs resting on the front wall. Are you not concerned about part of the oven resting on the foundation slab and the front resting on the wall?

I might be able to do something similar, but my wall is only around 24" tall without the capstone. If I rested the front of the hearth slab on the wall, it would have to be "really thick" to get a good height for the oven floor. I guess I could make the retaining wall taller in that area, but that might look funny.

btw, what is the recessed part of your vermiculite/concrete slab. The firebrick floor isn't recessed in that is it ?
thanks.

Zoltan

[deejayoh]

Re: Build stand into a retaining wall

I think you can use the location back wall as part of your stand, but I would not use the existing wall. I woudl suggest replacing the bricks with concrete filled CMU. I would also set them on a slab

[GianniFocaccia]

Re: Build stand into a retaining wall

Zoltan,

You can't really see it from the pics, but the concrete-filled base blocks butt directly up against the retaining wall (also concrete-filled). Most of the weight of support slab rests on the base, and merely overhangs the retaining wall. I am not concerned at all about the weight the retaining wall has to bear.

If your design includes a wood-storage area directly under your support slab, you could remove a portion of the retaining wall and build your base flush with the front of the wall like Dennis recommends.

[stlouisz]

Re: Build stand into a retaining wall

Thanks for the responses.

I had the installer of my retaining wall come out and he had two thoughts about my installation. The first was to replace the back and front wall and have the foundation built so that it would support the dirt on the backside.

The second idea which he thinks would be easier / cheaper is to make a roughly 50" wide U shaped return of the front wall onto which we could put the Hearth Slab. I have included a sketch of what this would look like.

OK...I know the FB instructions and most people place the block on a foundation slab, so I wonder if this second idea would be ok. I would think if the hearth slab is sturdy enough, it would be. Wouldn't it be equivalent to placing the hearth slab on gravel / grade?

For those who are weary about this, what if I extended the pavers (shown on the drawing), so that the blocks sat on them. I think I've seen pictures of this before, and this is how the metal FB stand can be used, right? However, I don't really see the added benefit of the blocks sitting on the pavers; it's not like they are interlocked or anything.

The company has an engineer on staff who will also look at these options. What are your thoughts?

[deejayoh]

Re: Build stand into a retaining wall

The issue you'll need to worry about is differential settling of the wall sections. With this plan, you will have a 5 x 7 foot slab sitting on a narrow footer (your wall) - so it is not really the same as slab on grade, where the weight is distributed across the entire section of the slab. The weight of the slab and the oven is probably more than the wall is intended to support. I would suggest pouring a footer for the wall that extends at least a foot in either direction. You probably don't need the slab poured in the middle.