DIY Wood-Fired Pizza Oven Construction - Initial Excavation For Foundation - February 2024

This past weekend, I posted a list of 'early potential priorities' out in the yard and garden for the upcoming 2024 growing season.  That list featured a number of projects/ideas/areas that *could* be something that I'm going to prioritize in 2024.  But, it also featured one item that has certainty when it comes to being a priority:  the backyard wood-fired pizza oven construction.

The location/site of the oven has been an open question for me ever since we moved in back in 2017.  I wrote about a couple of final options in the backyard in early January where I narrowed it down to two locations:  built into the berm/closer to the patio vs. down on the drywell, lower-elevation.

With the run of warmer temperatures this week, I got out one night after work and just got busy:  digging the foundation.  

I went with the drywell location.  Further from the house, but anchoring a secondary, lower-tiered patio.  Below is a look at the site - annotated to show the outline of the foundation as well as a couple of plants worth noting (orange = Hakeone All Gold Forest Grasses, purple = a dwarf conifer).  All of which...require transplanting; the only question is the timing on the transplanting.

At minimum, I'm looking to pour a slab that is 72" wide and 82" deep (6 foot wide x 6'10" deep). That would allow for a stand built from standard cinder blocks of 4-blocks-wide and 4.5-blocks deep (64x72 or 5'4" wide, 6' deep). That leaves an 4" reveal on both sides and 10" total reveal on front/back. What I'm not sure of (yet) is if the bottom courses will be built with 10" wide block (instead of 8") to allow for face-brick to 'sit' on that ledge.

Current thinking - using 8x8x16:


Stand: 4 blocks wide, 4.5 blocks deep. 64x72. (5’4” wide, 6’ deep)
Stand:  4.5 blocks wide, 5 blocks deep.  72x80 (6" wide, 6'8" deep)

Reveal: Front/Back: 3" each (6" total), Sides: 3" each (6" total)

Slab Total: 78" wide, 86" deep (6'6" wide, 7'2" deep)

If 10x8x16 block on bottom courses, that cuts reveals down by 4" each way.

Stand: 4 blocks wide, 4.5 blocks deep. 68x76. (5’4” wide, 6’4" deep)
Stand:  4.5 blocks wide, 5 blocks deep.  76x84 (6'4" wide, 7' deep)

Reveal: Front/Back: 1" (2" total), Sides 1" each (2" total)

Slab Total:  78" wide, 86" deep (6'6" wide, 7'2" deep)

Either of those reveals are adequate, but I'll continue to think about where I want to land.  For now, I've begun the excavation on an area that is 80" wide and 88" deep.  

Here's a photo (below) of the width dimension:

And here, below, is photo showing the depth dimension:

If the slab is 72" wide and the framing material is 3" (1.5" x 2), I'm at 75" wide vs. 80" hole.

If the slab is 82" deep and the framing material is 3" (1.5" x 2), I'm at 85" deep vs 88" hole.

When you add in framing support (another 1.5" each way), the number shrink to the point where I'm thinking I need to expand the excavation.

72" wide slab
+3" frame
+3" frame support
+6" wiggle room
Equals 84" total width excavation.

82" deep slab
+3" frame
+3" frame support
+6" wiggle room

Equals 94" width excavation

That is, pending my (own) confirmation that I want a 72" wide x 82" deep slab.

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2/22/24 Update:  I'm calling it now.  This is the way:

Slab Total:  78" wide, 86" deep (6'6" wide, 7'2" deep).

It works with both 8x8x16 blocks and 10x8x16 blocks.

8 blocks:

Slab: 78 wide, 86 deep

Stand: 72 wide, 80 deep

Leaving reveal of 6" total.  3" either way.  

This allows for face brick and a 1" reveal.

10 blocks:

Slab: 78 wide, 86 deep

Stand: 76 wide x 84 deep

Leaving 2" reveal all around, 1" either way.

This allows for facebrick to sit on the 10" block and a 1" reveal.

Now, add the framing and support - +6" to width + depth.  

Outside of material = 84" wide, 92" deep.

Add 6" wiggle room.  

Final hole excavation:  90" wide, 98" deep.  Allows for 3" 'wiggle room' all around.